-~J/:'" ,:' . ~" -, < -Z " :--. '.- '~--:--rr-~, -- - '''~~~''!'' <' :: --;-;-'..--:- ~~~\~ - , .';' f ,7 .. '\ .

, .

MAMMALS OF THE SEA Biology and Medicine

J.'tlil('(l by ----------------------------------------

S:\\1 II. HI])C\\'.-\Y

]!l'Sl"IIrcl, ,'cl('rillarillfl

(lCUtll Sci, lilTS J)'Ttirl,"I'''' ,\'(11'11/ [·'III.-rsCf/ RD, 'urcl, olld J)c('(i<'llllll 'lIl C"lIlcr

S UII ])il':":", Cf/lifomia

CIIAHLES C THOMAS • PUBLISIIEU Springfield • Illinois • U.S.A.

I,

. " \ \ .

I ... .

.--, ~ I ))

r. ( lail nJ II I l ,c'I. k!

, '\ \I /,;I, li, \ ' i I,. /Il. r

'. 1 I< :11.

CONTRIBUTOHS

HOIIEHT L. BIIO\P,ELL, JB.

Lt'. :\lIgdf'.l Cmlllly .\111,)1 ' /111/ of SIIIII/.d lIi \ tllly 1,11\ t\1I:,:dn, Cll/ifllmill

(I lid Dqw rlllll 'ul of I'III/III/,,:,:'!

1'/1(' )o/m.\ /Jul,kill .\ l'lIir""ily

nlllliIllOrl', 'III ry III III I

DAHl) 1\. CALDWELL

C 01/11111111 il"l/l iOIl Scir'llI'c ' \ La/ 'PTIlIMY

Flmic/a SIII/c' .H//\c',,111

l'lIirn\ily of F1l1ridll (;aiIlC'.\T illt ·. F!uridtl

~JELBA C. CALI1\\'ELL

Cnllllllllllira/iclli Scil'lIrt'.\ l.aJ,Pllllpr!! l lIirc 'I'.\;ly (If Florida Gaill(',\ri/lc', fioric/o

MURUAY D. DAILEY

Dcparllllelli nf ])jn/ngl! Califnrtlia Siall' enl/, '!:" Lnng Beach, Califortlia

~onnERT ). FLA~lGAX

Clra i rill a II , Dqwrtmrnl nf Binlngy 51. l\'nrlwrt's Cnllegc

'''est De Perc, "'iSCOllsill

MURRAY B. CARD~ER

Deportmcnl nf Palhnlnf!.!J Selwo/ of Medicil/e

Vnieersill! nf Snllihem CalifPrllia Cnullly--USC Medical Cenler

Los AIlgclcs, Colifnrllio

v

PUEFACE

Tlw {ir~t Jlltn\l.Iti~lJ,al SY\~T()sill\~1 Oil Cdat'l:all H"s\'arel~ \\ ' 01' 1,dd ill \\ aslllllgton. D.C.. III H)(j:}. Durlllg tlte S('SsHlll 011 practIcal pruh'I'lllS,

hotlt Dr. K('lllll'th S. 'orris, who c11ain'd tIll' IIHTtillg. all(l F. C, \\ '00(1, wit;) dlain·d tltat p;lrticular sessioll, sllgg!'st(·d that I try to ('stahlisll all illfol'Jllatioll ('X('h,IlI~I' regardillg lIwdical ('af(' alld Itmllalldry alll())'g 1)('1'­SOliS w()J'killg ,,-jtll lIl;lrilU' llIallllllals. All ('flort was Illad( · to start such a

data l'1( · OIrillglJ(lIl~'·. hilt it failed quit(, llliSl'rahly, III tlu' y( 'ars sim'(' tIll' first symposi\llll, hilllll(·dical illformatillll It:ls

<l('\'('lop('(1 fOlirly r.lpidly; tllll:'l, whl'll \11'. ]>OIYll(' Tllo'llas cOlltOlclt·d Ill('

ahollt th!' Il('(,d fllr a IlHlllograph ill ,this {i(,hl, I was ('agl'r to S(T if a

IIsd," II'xt coulll Iw dl,\'(·lop(·d to fill tliI' practical IIl'l'd for ill forlllatioll :lIld at th!' sanll' tilll(' !ll'n'(' as a \-alllal)II' rd('f('\H,(, for Sci(,lItists, teachers,

alld stlldl'llts, Tltndort,. w!' ~d Ollt to COH'r thl' hasic hiological amI Illl'dical Scil'lIl'('S

as tlH')' J'elall' to Illarilll' m:lIl1lllals ratlt('\' tl,all to (It-n'lop all a(h-alll'l'tl treatise' Oil CllrrclIt n 'warclt ill the fi('hl. Thl' l'olltrilllltors \\'l'n' ('howll hl'(';tIlS(' of tllcir {'.Ipability amI \\'illillglH'SS to COH'r a specific area.

I fclt that thl' t('xt shouhl contain a hrid introductioll to each sp('cies of marill!' llIallllll,ll. gi\ ' ill~ certaill hasic il,fol'lllatioll ahollt that specie's. ] askl'(l Dr. \la.s:th:ull 1\ishi\\'aki to con'\' tlte cctacealls, pillllip('ds. alld sirl'lIians, all(l hi:- illtroduction to tlww tlll'('(' ordns appears a!l Chapter 1. At Dr. 'ishiwaki's insist('ll('l'. I ask(,t1 Dr. :Karl Kellyoll thl' world's fon'lllost alltboril'y 011 the sea otter, to introduce that species ill Chapter 2. ]n tIHl~(, chaptC'fs, wc h,1\'e illcluded illllstratiollS of all those specil's for which spcciJJJ(,lls Or photographs ha\'c h('en a\·ailahk. \\'(' hope tllat these iJJustratiom \\'ill he helpflll jll species identification, though age, sex, all(l imli\-idual ,-ariation must be tak(,l1 into account \\'hen comparing them with thl' a (· tllal animal. \\'<, also hope that our scicntifie (,olkagues arouJld tbl' world \\'iII apprise \IS of allY "ariations that the)' find lwt\\'ccn thps(' illustration, .1IId tIll' allimals that th('y ohser\'(.' ill the field. TIH' tax­onomy of some groups of marinc mammals continues to be a mattcr of cOlll'ro\'('rs\-, and \\'c ba\'c not tried to still that contron'J'sv ill this work. Dr. !'\ isbi\~-aki has classified the Pinnipedia, Cetacea, antI ·Sirenia accord-

ix

x Mammals of til(' S( '11

illg to tlJ(' J,('~t c\ id( 'II(,(' a\'ailahle today, bllt Ill' i~ cardlll to poi lit (JIlt that

('('rtaill grollp~ lll ;tY han' to 1)(' reclassifi('u alld others cOlllhilll'd wlwlI lIIorc

stlldies 11;1\(' 1>t 'l'll cOIIUII('kd with larg(T JJlIIIII)('r~ of specillll'II~ ,

Chaptns 3, cl. allu 5 ucal prilllarily \\'ith allatolllY mid aT<' (ksiglleu to l'tlll\'('Y l);t~il ' illfllrtllatioll alHlllt the strudllrt, of lIIariw' 11I;lIllIllal" willi spe('ial ('llIplt.l,i, Oil strll<:tlll'al ddail n'(lIlin ,d for i(l<-lItifil'atiml of pa­

tll()I()~y, Clt:ll'tl'l'~ (j alld -; (It'al witlt Iwlta\ ior, ~1'IIWS, alJ(l COllllllllllicatioll,

with ('llIpll;l>i~ 011 those fadors illlportallt ill lIIailltaillillg a ('olollY of

marill(' Illallllllals. III Chapter 8, SOllie J)('\\' kchlliqlles for tilt' ('\ 'ollltiollary

cOlllparisou llf 11IarilJ{' llIallllllals an' discllsSt'd. aud (,11[1'1'111 tltl'oril's as to th(, origin of mouern-uay cdac('allS alld pillllipl'ds af(' n,yj('\\·nl.

Parasite's appear to Ill' thl' most illlportallt diw;lS(' PI'lII.it'lIl ill \\'ild , pOJllllatioll~ flf marille mallllllais amI an ' tl)('I't'ftJrc OIl(' oj tilt' first proh­

kIllS tllat IlIlbt 1)(' dealt witll ill a capti\'(' grollI', C1Japt<'r ~) H-pn'!'>(,lIts

the first cOlllpll'!I' c1wl'k list a\'aibhk 011 tIH'~(' parasit('s as \\'('\1 as a tahlllatioll (III hll~t locality alld a disl'lIssioll of ~IJlIH' of tIll' ilion' illlJ1lJrtallt

gl'IHTa. eli,lptn III is a discllssioll of tIl(' marilll' III all II lIal alld Ilis aqllatic ('lI\il'OlIlI)('II1. lIerl' W(' pro\'id(' illforlllatioll 011 our ('lIn('llt '!'>Lltl' of kllowl­

cdg(' COIIC(,rtlillg pllysiology, IIWllicilll', alld hIlS\J;lIl(lry awl illdlllg(' ill SOli\{'

Sp('Culatioll aho llt the future.

TltrOllglltll lt tltis kxt \\'(' Itan' h('('11 pmposdlllly n'l'kk~~ ill om ml' of th(' I'OIlIlJlOIl knm porpoiS<' alld dolphill and \\T han' (·llIploy(·dtht'm illter­chang('ahly in lIIost cas(·s. Following 'V. E. Scl)('\'ill , W(' r('cognize WI

clear distillctillll betwcell modern day lkrrill!!llOggida(' a III I til(' dolphins of ('arly Grer k lill'ratur('!

I alll greatly illdchted to many pl'opk wllO \WH' h('lpflll ill tllis ('Hort. \1 .. , Sit'\(' Ll·.ltlJ(']'wood assisted in \ 'irtllally ('HTY pltasc of tIll' lIJallllscript preparation. \Iy wife, Jeanette, assisted witll all tIl(' corn'spOllllcn('(' alld manus('ript preparatioll. ~Iaria Ridge , Pam lIayslctt , allll Yidoria Yargas

typed tIle filial manuscript, and ~fargar('tta FullC'r and Blltll Jackson hl'lpl'(1 with earlier drafts. I also want tn thank many others for thdr assistance and , · .. dllahle support. These inclllde \Ir. Bill Gilmartill, ~Ir. B. L. Scron('(', \Ir. ~1. F. Wintermantcl, \Ir. B. A. Powell , ~Ir. M. E. COllhoy, \Ir. F. G . "'ood. Dr, C. Scott Johnson, Mr. Georg(· Anderson, Dr. DOli 'YiI50n, Capt. Charles B. Bishop, }.ir. John Ropck. \Ir. Stanley Marclls, Dr. Sam Rothman, Dr. Jack Collins, and Mr. H. B. Stone.

S.H.R.

I ) poilll 0111 that ) 1Il.<1 \\ ,11<'11 Ilion'

i llH' II~ ,

tn · (k" igll(,c1 10

111;t1l1111 :lk wilh :t '/Il';ttiull Ill' Pd­I '1IIIIIIIlIlIic;l!ioll,

il ' a ('olll]I\' of tilt · (' ,'olll! iUllal'\ '

II I tlll'ori('s a ,~ to

' \ \(' \\ '('<1.

plllhklil ill wild )f tl\(' fir!> t pfIJ1)­)t 'I H rqm'wllh

(' a, \\'('11 as a

I llln' illlpllrt;llIt

I 11111 Ilis aqllalic ,I ,,1. 111' or kl)(I\\ 'I­

I ilH llIl)!I ' ill ~()IlH'

. ~ i II (III r II .'C of ~o '('11 tlll'lIl illln­

rccll)!lIiz(' 110

1 d th(' dolphins

fl I in this dfort. f 11\1' lIlallllscript

n ponclcnc(' and

'idoria Yar)!as

cl RII11I J ;1('ksOll

( thers for their J . i1martin, Mr.

;". ,11. \Ir. \1. E. ;C',)rgC' Andnsoll,

'P k. :\Ir. StanlC'y B. tonI'.

S.B.n.

CO:,\TE\,TS

l'uj'.£'

CUII/rilJI//ur" .. . .. , ... . .. . ........................ , .. , .... . .. ... ,., .. \.

Pre/acc ix

ellUl"'"

1. GE\:t:Il.-\1. Hllll.l>CY

.\fui>III/(/1'/I .\'j,/,irt'uki 3 3

6 (;l'!a{'I".1

Pilillip" :1 . 1 :,(j Sirt ·lIi.1 . . ........ .. ... . ............. ..... ...... . ............. H)2

H(·fen·II t'< " ,.'., ... . ........ . . .. ....... ... . .. ,.... ........... 20()

2. TIJI: S 1'.-\ Or r}];

] Il! rod ucti .. l:

BefITI·III ... '

3. 1'111: CE'\IJ: ~L :\'1:m'Ot:s SY~:~I

20.')

20.'j

214

.\'{)r/lI'rt /. F/UI';:!(/II .. . .. . ....... . ............................ 2]5 CI'! ;l( '{ '; ( ................... ... ....... .. .... . .. . ............ . 2] 5

232

4. OlISFH\'.-\TI ) '~ O\: Till,: :\\:,.,1-0:\')' OF SO\'E CtT .. CF .... XS ."X]l

P1XXII>!·:ns

Rohert f. Cree" .... .... . ... .............. . . .. ....... . . . . . .. 247

CI'!;ll'l':tn .-\Il:l tolll), ...... . ............ . .... ........ .......... 244

PiIJIJipC'd .-\n~ltomy ....... . ................... . . . .......... ... 274 Hcf ('r('l)l ... ··<: •••••••••••••••••••••••••••••••••••••••••• ••• ••••• 293

5. COMPAH.HIYI: \IJCRoSCOI'IC AN .. \TOl\n· m " SELECTED \lARIXE

M.n f\ f.>. LS

jol", G. Simpson and Murray B. Gardner ............. _ ........ 298

n"spirato,:' System . ... ...................................... 299

Cardio\'a~ war System .. ............... ... .......... .. ...... 324 IT fillaf\' S\·,tem ..................... . ....... .. ............... 333

xi

xii 3111lllmals of the Sea

Chupll'T Page

Diges tive System

Integumentary System ...................................... .

Lymphoid Organs .... .. ... .. .... . ........... . ............. . .

Thyroid and .-\drenal Gland ........ . .... . ... . ...... . ........ .

3-10

363 378 3S6

Reproducti \ 'e Syst(~m .. ......... .. ...... . .. .. . ..... .... . ... .. 39:2

Hl' fcrenccs . . .. . .. ... ....... ... ... .. ......................... -113

6. lkll.\\' /oll Of \hHI:-\E \h~I~!.\LS

.\[elha C. Caldlcdl (/II([ DaI;id K. CaMlcell -Il9

Cetacea ...... . .. .. ......... ..... ... . . ...... ................. -119

Otht.:r .\larilll' \1a/l1l11als ........ .. .. . .. . ... . ..... ...... . ... ... -1-10

Befen'nel' s ............................................ . ..... -1.57

7. S£:-\SES .\:-\D CO~DIU:-\IC.\TION

Dllrit! K. C(/Ic/lt'dl 1111(1 .\[e/l}(l C. Calt!ll'dl ..... ........ .. .. ... ·166

Cdacl';.t ............................. ..... . ..... . ..... ... . .. . ·166

Other \farill ' \lallllllals . . . . ..... ... ........ .. ........ . ...... . ·1.')6

lkfl'fI.' llcl's . .. ... .. .... ....... .. ................. ... .. . . . . .. . 1<)6

Dcf}(lTllh DlltJidd KIIIII

Ori~ills of tit' CetatT<l

CdaCl'all Emllltion ................ ... .. .. . . . . . ... . .. ... . ..... iO.'5

Cdat'I';1II Cyto~"Jlt'tics . ' ......... .. .. . . ... . . .. .. .. .. ....... .. . in Ori~illS of tIll' l'illllip,·tlia ... . . .... . .. . .. .. . , . ........ .. ....... ')17

Pi, III i [ll'd C~ togl'lll't ics ....... . ... ... . .... ,. .................. .'):22

HI'f..n ·ll cl'S ... .. ... . ........ .. ... ... ... ... . ... . ... . . . ......... i:26

9. :\ CJ\I·:C:"I.I.~r OF \I ,\III;\;/-: \h~I\I.\I. J> .\lI.\ .~ ITES

,HI/mil! D. Vaile,) (/1It! Rohert L. UroltliCI/. Jr .

Pi 1111 i pi'll i;l

( :oI flli, 'nr;l

.... . ... .... . , .....

C. ·Lltt ·;I .............. .... •.• . .. ......... •......• ........ • ... .i .. I·' Sin 'llia ....... . ................ .. .. . ....... . ... . . ... ......... "i6l

r.i~t ()f P.lr.l,itl· (;1'11I'r;l alld r.'lt'alitv ill TlIl,t ...... .. ....... . .... . i 02

H"1 1r. ·"",Ltli," ·' ()r (:OIlIIlHlll I'ara\itil' (:r. lll p' 1-'llillHI

ill \I.trilll' \Ialllrnals .............. . ... ........ ....... .... ... . . ,,)G7

10. II()\n:()sT. \'I.~ I ..... Tflr-: "9U,\T/C E:'i\'lIlO:'i\/I-::'iT

SIIIII fl. Ritl!.!II ·II/! . ................................ . . •.. ..... . . i')O

itlLkgrollll!1 ... .. ....... .. ..... .. .. .... ... . . ...... . .......... .i<)O

Chapler

Rcsp Car

OX\"

The

Hefe

Xlllll e I/l(lcx'

Sf/vjed Ilid

COlltents xiii

Chapter Page

Respiration ...................... . ........................... 591

Cardiovascular Adjustments ..... . ... . ... . .................... 597

Oxygen Stores . . .... .. .. . ...... ... . ... . . . . . . ... .. . . . . .... .. . 603

Thermoregulation ....... . ... . .. .. . . ...... . ................ . .. 607

Osmoregulation .................. . . . . . . . . ................. . . . 6ll Reproductive Physiology .......... . . .. .................... . .. 6:33

~(isccIlaneous Physiological Considerations ................ . ... 635 Hematology and Blood Chemistry . . . ......... . .......... .. ... 65:3

Diagnosis and Therapy ......... ... ............. . ............ 70-l The Future ........ . ....... .. ......... . ............... . ..... 7:26

Referellces 73l

.\'allle Illdex 7-19

S"bject Index ................................. . ..................... 7.39

elw plf'J' ]

GE~ERAL BIOLOGY

\I. .. ,s-\JI.-\H\ . :\J~IIJ\\ · .-\"J

TI)iS chapter is illlt·lIlJt.d to S('f\'(' as all illtrO(llIdioll amI ~lIide to tIl(' \'ariolls ~I)('ci('~ C()IIIJlri .,ill~ tl)(' ~rollP of aqllatic allilllals kllo\\,11

coll!·din·ly as tIll' marill!' m;llIllIlak TIl(' foll(l\\'ill~ arc tIle thn'(' basic ta\()\)()lIIic ('atl'gori('~ ( ord('rs) of Illarin(' mamlllals: Cdac('a. \\'hid) ill­cllldes tll(' porpoi'l" ( or dolpllills). amI ,,·!tal(,s: Pinllipedia, wllich illclll<l(" seals, sea liolls, amI \\'alrllsl's: alld Sircnia or s('a co\\'s . Anothl'r marill(' mammal, thl' S(';1 oller, EllhlJdra I!lfris, a l11<'ml)('r of th(' oder CarninJra . \\'ill 1)(' dis('lIss('d ~( ' p;lralt-ly ( Chap\!'r :2).

Th(' lIlorpl\(Jluf!ical (ksnipti()lIs ar!' illCIIl(kd primarily to distillglli,11 c;Jch sp('cies from otlH'rs ill thl' same gelllls . The Illore fundamental charac­teristics, thosl' COIIIJllOII tll the gl'nus, are illcluded in the <I('scriptioll of ~enlls. falllily. or slIhordl'r. ] I1l1stratiolls art' prO\'it!(,d for all th(' speci('s for \\·hi('h a SI)('ciJll(,1l lIas heell :1\'ailahh-, The' scielltific names are prinll'd in itali('s. a1l(1 ",hen they apl)!'ar for tIl(' firsl tillll' are followed by the clrri,­telleT amI tIl(' yC'ar (If Ilalllill~,

nclati\'e hody IlH'aSlIff'l11ellts are importallt fOT species idelltification, but SiIlCl~ specific, ddaihl data is required only by sp('cialists. li II 1<. is included ill this tex\. \felltions of hody size usually refer to the size of tIl(' m'eragc adult, thollgh therc is occasional reference to maximum Icngth . "'here ollly a limited IlIlmhcr of animals of a species ha\'e )('en al'L'llTat('ly lIH'asl))'ed, Ill(' fCplJrlC'd sizcs rcprcsent all estimate hascd 011 the spc('imclls a\'ailnh1c,

The' lllC'aSllTClllents us('d hy tllC all thor arc as follows:

TOTAL LI·:.xCTIl: ~kasurcment in a line parallel to the body axis from the front tip of the rostmm to the not<:h at the posterior edge of the tail flukes .

HEAD A:-.-n BODY: Totallcllgth minus length of posterior appendages (not u sed for cd aceans ) .

3

4 .\llImmals of the Sea

~L-\Xl~lU~( WIDTH OF SKlLL: Generally, zygomatic breadth of pinnipeds,

mastoid breadth of other species.

M.-\,.'{n(U~( \VWTH OF BIl.-\l:\CASE: Cranial measurement aoon' the zyomatic

region.

UPPER CHEEK TEETH: Distance between anterior edge of upper cllspidate tooth and posterior end of last molar, measured either at the crown or alveolus of the tooth (lIIethod of IIIcaSUH'nH'llt IlImt be 1I\('ntio1lcd)'

UPPER TOOTH Row: Total length of the upper tooth row is generally measured from the allterior end of th " first incisor to the posterior cnd of the last molar tooth. Cetacca arc ~tl\\'ays Illl'aS"llrcd at tIl(' ah-t'olus. l1l'eallst' some species bek teeth on the uPFer jaw, the 100wr tooth row should also be measured and recorded.

LE:\CTH OF SKl'LL: Although the length of tlte skull is Illc<lslIn·(1 at thrce

positions, the condylobasal Iell~th is Illost eonlIllOltly used. 1. ~[a xi 1/111 III colll/Ij/uha,wti Ie IIgtl!. The Ii IIl\\r dis tance from the pos tc­

rior surface of tIll.' occipital condyles to thc anterior end of the nlaxillary (llot inclllding teeth). TIlt' cOlldylllhasal lellgth in Cet:ICl'3 is l'qllh':Iknt to the total ICllgth of the skull.

.) Total lellgth of the skllll . . \ linear IIIl':L,;urCJIll'llt fWIll the allterior to the posterior l'lIll of the skull, parallel to the hody axis (teeth

l'xduded ). 3. Hwilar /clIl!,th. :\ litH 'ar IlIl'aSIlH'IlH'nt frolll tlte front ('nd of the

for:III1l'1l tnagnlllll to the posterior end of the central incisor tooth socket, parallel to the hody axis (not applic,lble to cetaCl'ans).

BODY \ft.: ,\scm:~n::,\Ts: Thl's(! an' all lilH'ar 1ll(':ISllrCIIIl'nts and are taken para'lh'l to the hody axis.

1. Total len~th, from the tip of snollt (lIppcr jaw) to tit' notch in the tail fill kl's.

2. From tip of snout to center of hlowhole. 3. From tip of snout to center of ('ye. 4. From tip of snollt to gape (corner of IIIBntlt). . ..,. From tip of snout to anterior insertion of lIipp('r. 6. From tip of snout to tip of flipp('r. 7. Frolll ('ar ()pl'nin .~ to u'nt('r of ('Y('. H. From notch of flukes to tip of dorsal fin. 9. From notch of flukes to Ct'nter of anll~.

to. From notch of nllkes to cellter of the gcnital opening. It. From notch of f1l1kes to crntcr of nan'l. 12. Frolll lIutclt of flllkes to po:o.krior I'lld of \clltral grooves.

FLIPPEn: 1. From :tnkrior inscrtion to tip of lIipper.

2. From 3. \laxin 4. From

DORs,-\L FI:"l

1. Lengt :2. Heigh 3. From -t. Poster

T"IL FLl'h:E 1. Total .) From

.3. Frolll -t. From

CL\SSIFIC.\TJ

is hased liP' 1. C L'l't i<

Tltl's' 11\ SOil

\'Crt(+ IIcr\(' \'(Ttcl:

:lrt' k .) {hora

TI II.' fI last ril hrac. \'('rtel

3. Lilli//;

C hCH(

pr()l'l',' .l. Carlll,

attacll tholl ,~ 1 as~()c i

till,l.!;ui oss i fit' is not

1'11.\ I..\:'\ct-; ,\ L

spccthely. I one pC'r fin ,~

hoth type.

General Biology 5

2. From axilla to tip. 3. ~Iaximum width. 4. From anterior insertion to tip around the cun"e.

DORSAL FI:-l: 1. Length of base (not necessarily parallel to the hody a:xis). 2. Height. 3. From anterior insertion to tip around the cur-"e. 4. Posterior insertion to tip around the cun"e.

TAIL FLt:KE:

1. Total width (or spread) of Hu kes (straight line measllrl'lIlent). 2. From notch to tip of fluke (both sides). 3. From notch to nearest point on anterior border. 4. From notch to anterior in~ertion"

CLASSIFIC.-\TIO:-l OF YETEIIIHL BO:\ES: Deri\"ation of the vcrtehral fomlllla is ba.'ieu upon this cbssification.

1. Cerdcai certciJroe (C). The first s('\"('n \utebrae posterior to the skull. These are lacking rih attachml'nt" The cen"ical \ t.'rtcbrac arc fused in some species, completely free in IItlll'rs. \\ "I\("n they arc fused. till' \"ertehra can he detected and cOlillted hy ohsen"ing the Humher of I\('r\"c hllndles arising fro1\l the spinal cord. Occ;billllalJy, the cl'n.ical \('rtei>rac arc foune! to have attached, hilt incolllplete, hones. Thes(' arc termed eerdeal ribs auu arc not considered to he true ribs.

2. Thoracic certchrae (T). The v 'rtehrae to \\"ltich tnll' rihs arc attached. The first one to se\"('ral rihs an' gl'llt'ralh- joinl'd tl) thl' Sll'flllllll" The last rih is ofll'll a ""floating rih"' with no direct ;ltt.lclullI'lIt to a wrtL'­hrae. For this n:ason it is easily o\"('rlookl'd. The llllllllwr of thoracic \"('rtehrae is ('qlli\"al 'nt to the 1I11111111'r of rib pair,.

3. L'llllh(/r I.:crtclmu.: (L). The \('rtl'hrac to which lIeithcr ribs I\or chc\Ton hones attach. They arc I'asily identified hy tlwir trallW('fse [l)"()("('SS('S .

. 1. C(/lId(/1 urtl"iJrlIl' ( Ca). Thl' \('rtl'hrae to which the ch('\Toll hone'> attach. Thl' l'hc\fons S<'rvc ~IS attachll\('lIts for caudal mllsch,s. :\1-though til<' :Il\tl'rior l'hcnons an' ,btind alld I'asil~' n'Co!!;lIiz("d, those ;\S~llci;lt('d with til(' llI11St pmkrior \"dl'bral' arl' difficult to dis­tillguish. Fllfther, lIIany of those v<'rtebrae LIck attachmcnt to ossified chcnons. For this rC'aS()II, til!' nlllllhcr of calldal \"(,rtl'hrac i"'i \lot ('qlli,";.Il'tlt til tIll' llllllllH'r of c1H'\Tllll hllll' "' "

PIL\I.\:\r.E\I. FOl!\11·[."\: ( alld " rcfC'r tn the' first all(I St'l"01ld fillgl'rs re­spcl'IiH,ly" Ikcallw it is difficult to ~l'paratl' the IIIct.ll·;lrpals, (gcl\('rally onc per finger) al\d phalanges, the nlllllher of honl's indicated int:h,d's both type.

6 ~[lIl1l11wls of the 5e<l

DL::::'IiTAL Fon~(l"1 .. -\: There are a \aridy of ways to indicate tll'ntal formllla. For example, odontocetes wSIIally ha\'e a large number of uniform t(,cth and the author indicates the numher of teeth hy a fomlll b stich as. ;j:~: . The numbers above the line refer to the teeth of the uppl'r jaw, those he­low the line the teeth of the lower ja\ ..... The range of indi\illllal \'ariation is indicated for both upper and lower jaws.

CET.\CE:\.

There are three suborders of Cetacea: .\rch;lcoceti, ~rystacocNi, amI Oclontoceti. The first, reprl'selltecl from the Eocene (a specilllell known as Zeuglodontia), OIi<1oct' nt', alltl \[iocclle epochs. incllldes ollly l"xtinct species and is not discussed in this chapter. The rl'lllaining two arc dis­tinguishable from each other primarily hy their types of (\t-lltition and the structure of their shills.

AU species of Cetacea ha\"(' kdh. at 1l';\St ill the f,'1IIllS, <luring the feLll period. Tn the ~[ystac()ceti, hO\\"l'\l'r, those teeth 1I('\er l'IlH'rgl' fmlll the g\lms, e\"l'n a fter hi rt h, hll tare f('P laced instead hy ha Iccn plates wh ich ,emerge from the palatine ridges ;111l1 serH' as foml collectors. Odollt[)('l'Ii, 011 the other hand, ha\l~ no hal('('n awl rd;lin thl'ir tedh aftl'f hirth. Th('re arc SOllie species in \\'hich those t('dh f( 'III ;lill ill,idl' the glllllS throllghollt life and others in which th(· tooth,hape alld p[),itiol1 c1iffn 1)1'1\\'('('11 thl' SI',WS, the females haying slIIaller tel'll. which sOIlH'tilll(,,~ do lIot ('IIII'r!,!(' ;It all , Though sOllie fossil Odolltocdi han' p()l~ forlll Il'l'th. lIIost lidnL: ~p('ci('s ha\'c ulliforlll kcth. Flllike llIo,t otlll'r 1I1;IIIHllals. Odolltocl'ti han' p('r-1I\;\\)(,lIt delltitioll alld 110 lIIilk t('!'Ih.

The li\'illg allilllals illl:lllt\('d ill tl\(' ordt'r Cdan';l rallgl' ill si/(' frolll I to J() III allll han' the I)asi(' 11Iallllllaliail c'haLlcl<'ristic'i hut u\llike other IIlalll­lila Is, il1cllldillg 1l\( 'lIIhcrs of the' ord('r I'illllipedia amI Sin'lIia. sp('11(1 LI\('ir ('Illire lin's in tl\(· \\all 'r, r II a(hptill!,! to that l()mpldely aqllatic , lift" tll!'ir bodie'S ha\'c lH'coll)(, g('I)('rarr~ ' 'pind!(, shap!'d ali(I sLn·allllil1l'd. Sflll\(' havc a dorsal fin, others dn 1I0\. 'I'll!' ton'lilllll'i ;Ir(' trallsfomH'd illto rill-,hap('<\ tlipp('rs. ;\IId thon~h a tra('!' fIr ft '; lr lilllh .. ap(lc,lr .. as a proj!'cti()11 (Ill tllf' ('arly d('\'('I(}pill ,~ felllS, lbe war lilllhs kl\l' d('gl.'llC'fatl'd alld callilot hc ohwn'('(ll'Xt('fIIalk aftl'r I,irth , TIl(' ,kill at the ('11(1 of tl)(' tail has d(·\'C·lolled - , illto a hori/()IJlally IHI,itillll('d ,\\ illl III ill!,! (Jr',.! III kllO\l1I a-; a flllk(', Jfl,1 1IIIIIn tIll' "l)id(,T1l1is tlwH' i, a rdali\('ly tllick 1>1111>1)('r Iay('r, fOTiIlt'd of fat alltl denllis, which aids ill IIlaiIiLlillill'..! 111)(1~ ' t('III(1I 'r.ltllf(' ;l1Id ill r('<lII('ill ,~

specific gra\'ity. Thc IIll'itrils kl\(' lIIi~ral<'<I to tIl<' top of 11.1' II(·ad. lwr­rnittillg th(~ allimals to 1)I'('all)(' \\hil(' S\\illllllillg at filII sp(·(·d ('\;Illlillatioll of the skeletol1 shows that tl\(' ll;\J'(''i actllally Opl 'lI ahollt thc middle of tllP

face and th appearance

Fetuses

sensory 0

Cetace

tindi\'c, ot her hOlles

The gesta or slightly 1

( s pcrlll \\' II; locatl'd at e and hdatil

Thl! disti l fo \lows: lao

I. Olltl'r ,J T('dh .... Balel' , ) ,

,I. COIl\ t

Illaxi ], , ), COIlIl :

Ihor;\'

\ klll!H'rs (j III as a<ll1l ja\\'s, th('y ;1 pbc('d hy f, The shape.

General Biology 7

face and that the fnrward ,~ loll~ation of the j;\\\'S C,ll\ses the "mcrhead" appearance of the blowhok).

Fetuses of all cet,\cean species haH' hair on their snollts. like the rOllgh or tactile hairs around the mouth of a dog or cat. Thollgh most Odontoceti loose their external hairs soon after birth, ~[ystacoceti retain tl\l'1\\ as sensory organs throughout their liH's.

Cetaceans haw an cxtrallrdinarily \\'cll-de\'t>loped skllll, Ht'\ihle back­bones, and ten to twenty ribs. Odontoceti ha\'e a wel1-de\'eloped sternum, but ~[ystacoceti ha\'e a small stcmU\11 which is joined to only nne or t\\'o pairs of ribs. (Cousiuering this rather weak thoracic stmcture, it is not surprising that stranded hah't'n whales may suffocate lllltkr their 0\\11

weight.) Whales lack da\icks. Except for the joint with the scapula, there is no moveable joint in tht' forelegs . There are always tracl'S of peh'ic hones, hut those bones art' Ilot joilled to n:rtehrae, Tran's Ilf ft'llII\r and fibula are attache(l to tl\l' pl'kic hone of some species of Balal'uidae . .\t the anterior portion of the coccyx, the V-shaped cheHons ,Ire \'t'ry dis­tinctive. The vertebr;\l' lie along th' midline, hut IH'ltlwr they lIor any other hOlies l'xtclld illto the Llil f1l1kes .

The gestatioll period of \ I y~taclJ(.:di is most frc'plclltly 1,11'\(,11 llIollths or slightly more ; that of Odolltocdi is gellerally a year or slightly more (sp('nll whales relllain pregn;lIlt Si\tl'l'll lIlonths), Olll' pair of lIippll's is located at l'ithcr sidl' of IIII' ~l ' lIital ~lit. ThlTl' is olle calf per prl'~II;1I1<:y, alld lactatioll COlltilllll'S fur six to l·ightel'll IIl1llllhs.

Suhorder 'iysta('ocdi

The distillgllis1till~ characl<'ri~lics of the ~lIhord('[ \fystac!lcl'Ii are as fo 110ws: la.

1. Outl'r 0p('lIill~ of 11I)~tril hil'artill', ,J 1'1'1'111 ahsl'lIt throughollt lifl' aftl'r hirtJ .. 1. Bah'I'1I pLtt('~ prl'WlI1.

I. COII\,('X profile of "[llll'[ ~nrfacl' of skllil (lllail11y lIlaxillal' amI pre­maxillaI' .

. ). COlllparali\ ely ,~I1t;\11 ,1"[1111111 alld poor ~\..I·ldal ClHlstnlctioll of thorax.

\kml]('rs of 1'\-1'11 Illl' ~lllal1( "1 'llI'l'i('s of thi'i ~lIhmdl'r [I'al'h a 1"II\!lh of () 111 a~ ad,dts . . \llllIlIl\!h IIII' I,ll , h;IS t""lh 1111 !tilth tlH' uppl'r alld 1()\\'I'r jaws, they are (k~I ' IH'r;\t('d ;lIlIl ;d"flrlwd I/y th(' tillll' of hirth alii 1 an' r('­placed hy from l.'j() to I()O hal""11 plat.·~ III \ thl' p;t\atille ri<ig('s of all ;\(ltdt. The shape, color, alld Illlmh('r of hall'l'rt piait's \-ary according to spl'cil's.

8 Mammals of the Sea

The skull is extraordillarily large, comprising one-third of the total body length in some species. The cen'ical n~ tcbrae are fus( 'd in some specics but separated in others. Only one or two pairs of ribs join the sternllm. Although the bones of the rear legs are usually absent, some species of Balaenidae retain traces of femur and fibula. E\'en in those species, how­ever, such bones never form any external legs except during fetal life. Generally, a cecum exists in members of this suborder. Baleen whales feed mainly on krill (snLdl crustaceans), but some specics also eat small pelagic fishes.

The three living families are Balaenidae, Eschrichtiidae, ~ll1d 13alaenop­teridae.

F .H·(ILY B .-\L:\E:-:!D ·\E

Some characteristics of Rllacnidae arc the follll\\'illg: 2a.

1. :\0 vcntral grooves or creases in skin of throat. " Head Ien~th IllOf ' than olle -fourth of total body length . 3. ~laxilla(" premaxilla " amI \Olller constrllct a 10llg narrow arch . .l. Long and narrow halecll plates; IlWrt' thau t\\'o hllndred platl'S '1I1

a sidc . . '). Sevcn ccrvicals all fllscd.

This family i~ characteri zl'd hy \l'fY Ilarw\\,. LlIr\'1'l1 maxillary alld pre­maxillary hones. Thcre' are halc(,lls alon~ the 11l\\,1'f ~ide of thl' Illaxillary. The <.:OlHlylohasal length of tl\(' "kill! re,lati\(' to tIll' toLlI lcll~th inl.'rl'aS('s as indi\'idllals gro\\'. S()Ill<'tillles altaillill~ ()\'('r !llll,-follrth ()f tlw total 1('llgt h. Tlll're a r{' lll'i t Iwr groo\'l's Oil thc a hdo III l'1l 11m t h roa t l.'r('asl's. The three li\'ing gCllt'f;l art' Babl'lla. Ellhala(,lla, and Capl.'rea, eaeh repr('s('llt<'d hy a sillgle specil.'~ . Some scil'lltists lI11itl' genlls Ha(a(!11tl a III I gCllllS h,­!}(/(aclllL allli form a separat e illtil'llCndl'llt faIllily \\ 'ith gellils Capen·a.

Balaclla

Some characteristics of Ha/!I(!lla arc' the follll\\'ing: :la.

l. Siz(, hr~,·. 1I11lfl' 111;111 I.') III ill ll l)d~ ' l, · n~th.

2. :\0 dorsal fill . lIippl'l's fairly Iar~e . . '3. Ball'cn plait's IOllg and nar~l)\\, ( 2 .. ) III allt! 30 CIII r('sp('cti\l'ly ) :

more than thre\' hlllldrcd platt'S Oil ('ach side. .l. Fiv(' fingers ill flipp('rs. .'). Body color hllll'i~h gray ",ith pal, spots. 6. ;";0 honllets ( \\'art-lik(' projectiolls Ill! ~kil! \.

Ba/aena Illy

- -

Fi~lIrc 1-1. III 11. 1l·\IS ill 17.).'

OTllEII CO'I

\lClItI'IIOLIlr. ·

hotly kngth hilt later III

onc-third 0 1

reports were or hy llH'aS ' hody lcngt~ in the tail

The hod) ('('ported Sl.' Oil II nders i< r"I)llrted til or gray col. hllll.··hlack hillc. ~lallY

The fhlk. arc loca ted on the hod 1.3 cm wid(

General Biology 9

Balaella //Iyst icetlls

' "

Fig ure 1-1. Ba[(/(: /I(/ lIIyslicclllS, kllowlI as the Grl't'lll.lIlu ri~ht " 'hall', 1I ;IIIll'li h~ ' Lill­

lIat 'liS ill 17.'58.

OTIiEII CO:'\L\IO~ ~ ,\\IES: Bowhead, great polar whale, arctil' right whale.

\(OIlI'1I0LOCY: Gn:elll.llld ri~ht whales an' Iw\i('Ycd to rcach a maximlllll hody lellgth of :W III. \f<oaSIlt'<'IIH'IIts of :30.:3 to ::m,6 III W('fI' Olll'(' recorded, hilt later meaSUTl'lllCllt of cOll{lyl()hasal Ien~th ( which is apprtJximatcly one-third of total kngth) of these two spccimcns cOllfirllled that the reports ,vere in erroT. TllCs • crrors were probably callsed by ('xaggnation or hy lI1l'aSlITelllcnt along thc clln 'c of the hody. The valid lIleaSIIr(, of body length is tIll' straight line from the tip of the maxillary to the notch

in the tail nukes. The hody of these whales is gCIH'rally hlueish gray. Scoreshy (11,7-0

reported seeing a ,~pt'ciJl1('n in which the white portion (Ii ,t!;ht coloring Oil undl'rsidc) cxtl'lIded to the antl'rior part of tilt' IIpper jaw, lie also rl'ported that sOIllI"pecilllens arc l'overed ,vith white spots, that white or gray coloring pr('dominates with old individllals, that til(' lIewhorn arC' hhll'-hhck in l'olm, ,IIHI thaI the 11llr~iJlg YOlln!.,( ;In' pall' "hI(' to !.!r;l~ ' i~h hhle. \rany indi,'idllals have pal(' spots all ()\ 'C'r the hody.

The IIlIkes are ahout (i to H III ill width (total spread), The hlowholes arc located abollt ,'5 III Iwhilld the tip of upper jaw, ncar the highl'\t point on the hody. There . arc approximately :360 yellowish-white halecll plates, :),'5 em wide and :3 1Il long, Oil ('ach side.

10 .Uammals of the Sea

The st.'uil is very large (see Cha'pter 4). The maxillary amI mandihle are long and narrow but widen near the eyes. The mandihles extend forward along the lower edge of the lower jaw and are rather lIat horizon­tally. The vertebral formula is C7 + T13 + LIG-l:] + Ca2:2-24 = .5:3--.5.5. The phalangeal formula is I: 1, II: 3-t, III: -1-5, IV: 3-t, and V: 2-3. There is a trace of hind-kg hones.

DISTRIBt;TIO:-l :\~-n \IICI\..UIO;l;: This species is limited to the northern h<'misphere. During the slimmer it is found in the Arctic Sea, but when the sea hegins to ic~ m 'er it moves southward in what is presumably not an extensive migr~ltion.

AmJ"XD.\:-,;cE: This \U,S the most important species in sixteenth and seven­teenth century wluling amI was ahundant at that time. IIow(,H.'r, OH'r­whaling has Sl'\'l'(l'ly redllced the population, and at present, it is belicwd that only a few snull groups ('xist near Greenland.

FOOD: The prilllary foo<l is slllall plankton, mostly of the gellus ClIIlIllIlS

or COPl'IWdll, The prilll;lr~' fceding "round appears to hI' Jwar till' iC('ficlds of th' :\rctie.

REI'H(lDCCf(O:-';: CI)plIbtions oCcur in Jatt' Slllll1l1t'r, and adults accolllpany­ing young are fr('lIm'lItly ohsl'rH'd ill spring. There is geuerally OIJ(' fdlls per pregnancy, hilt Scor<'shy ( lS7l) reported sITing w!tat aplll'arc'd to he twins nllfsing and illmtratcd his ohwn·atioll.

E"iJaillClIll

Some charactl-ri ,t it's of Ell 1}(IIl/clla an' the followi Ilg:

:lb. 1. Size large. 1lI0T<' tklll l.'i 11J ill hody length. .J Xo dors;ll fin. lIippns fairly large. 3. Baleell phlt', l(lllt! and 1I;lrww (2.0 III al\cI :10 l'1lI respl'ctin'ly); less

than :2.'50 pbfl'S Oil each side . . l. Fi\'(~ flllt!l'rs ill lIippers,

.'). Body colm hillt'i~h hLlck "ith 110 pale spots. 6, HOIlllC!>; pn" ' ·lIt.

Eubalaella

Fi.~lln· l-2, LIt

\ I Oil l' II()\.( )e Y

and h\' the ! which ~Ir<' it~

the anterior , of the alilni, side of the II ol\e of ",hid the lower lip

tota I 11'lIgt h of t he hod y wilh a Clln,'

an' milch ro TIll' 11l<l.\ill

alld 17,0 111

.t:r .1yi.,h hhll' hLlck to hLt fOlilld ()Il th, i 1\ color alld

The lJIallll\1i

~I:tllds ;If(' \ .

C('lIcral Biology 11

E"b(/laena glaci(/[is

Figurl' L-::!. btl" tftl t /Ill ,::'{tlcilliis, kllOWII ;IS the right whale, 1I;1l1l1't1 b~ ' IIm!)\\',ki ill 17K I.

OTlIEI\ C()~I~I()" :\.nIE : Blaek right whale.

~1()III'II()L()CY : This ~[l ~Ties is easily idelltifiahle hy its flllllld alld fat hody alld hy tht' hlJlllll'ts ( larg' wart-likc ;\ft'as formed Oil the ( ' ~t('fllal skill) which art' its IIlIJ ~ t t'h ;lrad('ristic fcatllrC. The largest hOlllld is located at tlte allterior of tilt' up[ln jaw. alld the IU ' 7\1 Iar ,~est arc fOlllul Oil hoth sides of the allterior portioll of tlte lowt'r ja\ .... Ill'hil\d the I',!tl\\,!tole. Oil the out­side' of lite IU\\'l'r j;I\\' . Ihnc is a series of sc\'cral slllall. rais('d ar(,as, (' aell OIlC of \\,hich is till' 11;\ , 1' of all appar(,lItly tactile hair. TIl(' up(ln ridge of tl\( ~ lowcr lip is </llitl' hIIlIlPY. Till' hcad compris('s ahollt olle-fomtlt of the totall(,II~lh alltl til(' total spread of the tail flukes l'IIlIals ailollt :n lH'rct'nt of the IllHly Ie II ';.!t h. Bllth IIlaxillary alld premaxillary art' projected forward \\ il I. a cline'. fl)nllill!.!; all arch, TIlt' hristles of the oli,c hlack h:d( '(' 11 platt·s arc IIl1lCh rOIl';.!hl 'r Ihall thoS!' of Hall/ella III ystin: lIIs.

The lIIaxillllllll hody 1!'Ilgths [('corded to datc arc IlL ) III iT! tht' Atlalltic alld 17,8 III ill tilt' 1';ll'ific . Tht' 1\('\\'hOl'II arC' ahollt ,j to fi III lOll!,!, TIl(' gr;lyisll 11111(' I''ilk (,1l1,,1' Ill' IIII' yC""I~ dal'kl'll~ ,, 'ilh o..:I' ,,\\'lh to lilt' hllll'ish hlack to hlack color of adllils. \Vhit c spots of im'!.!;lll.lr shapl' arf' oftI' ll fOlllld Oil lilt' ;lhdc lI lIC '1I Iwar tlH' lIa\l'1. TI\( , ton!.!;I\(' is Ihick. hlllt'ish gray in color and r('lati\('I~' ~llIalkr thall that of othl'r spl'ci('s of ~Iy"tac(}cdi. The 1l\,lIl1milLte an' locat('d at the in!.!;lIillal [( 'gioll . ;111<1 Ihe IlIallllllary glallds arc \Try thick 1; 1." IIIIICIt as 10 CIII ('\'('n in illllllatllf(' f('male,s) .

12 .\1 (/ /I III III Is of the Sea

The testis, which may be only 1 to :2 kg in juveniles, m~\y grow as large as 1,000 kg in weight in a fully matured breeding male. The hluhher is very thick (as thick as -10 cm at the breast and hea\y portion of hack) and contains fat of good quality . The \ 'ertebral fornl1lla is C7 + T1-l­I.5 + LU-lO + Ca:2.3 = 5&-57. There are fourteen to fifteen pairs of ribs. The phalangeal formula is I: 3, II: 5, III: 6, IV: -t (+1), and \': -1. The number of finO'er bones is subl'ect to some indi\'idual variation . .:>

DISTTImCTIO~: In the southern hemisphere, Ellba/aella are found sOllth of 200S and north of 5O~S and in the northern hemisphere the r ~Ir(, found be tween lOON and 70 ~ N in both the Pacific and :Ulantic OCl'ans. SOllie inhabit the :\rctic Sea. Since the distribution and mi grations of this species in the .\.tlantic Occan ~\re often confused with those of the Grecnland ril!;ht whale, the northe rn limit of its distribution has not yet been deterlllined.

Am; :\[),\:\CE: - The abundance of Ellba/a/!I/(t in the sOHthern hClIlisplll'rt, is

unknown, but since rl'[,)orts of sightillgs of this species arc \l'ry rare, they arc considerc (1 vcry scarcl'. :\t prl'Sl'nt, sbllghtcr of hbck ri~ht \\'kill's is prohibited hy the [ntcrllatiollal Whalillg ClI\\'l'nlioll, Si~hlillgs ill the Pacific are more frequl'lIt than in the ,\tiantic. [n the :\orth Pacific, SOIlI' anil1lals arc fOllnd north of the Bl'ring Strait, ill the _\rdic Sl'a. TI\(, lolal world population is l'stilllated to he frolll a f('w llllndred to out' titolls;(lld animals.

FOOl): This species is ratl\('r sl'kdin" feeding IlImtly Oil sllull C(llW[>ods (Ca!rl/III" .\f;I'rf]Ca/rllllls. Pst' lIdol'lI/IIWIS, O;tlill//ll. ;lIId ,Hl'lricl;II),

HEI'I\( 1Il l'CT I 0:-'; : Cop" b tiolls ha \' , 1)(.' ('11 oi>sl'n'(,d from l·\,hru;l ry to, \ pril, hilt the hrc('e1ing Sl'aSOIl prohahly lasts about half a YI';If. Thl' gl'stalioll l)('riod is t\\'e1ve lllollths, allli there is 011(' felus p('r pfl'~llallcy.

BEll \\' 1011: Black right whall's arc slow swillllllers, Dmilll!; tlll'ir migratiolls they ~\'llI'rally swim :2 or:3 kllots (:3.7 to ,'5.6 km/ hr) auel ('\1'11 \\'111'11 startled th(,), swim no faster thall ,'5 kuots (D,:3 km/hr ) . \\'hile S\\ ' illllllill~, 1111')' \\'ill hlow t\\'o or threr' tillie'S per lllillllte for se \'('ral lllilllltl'S :lIlel 11\('11 lIl;lke a IOllger allel prohahly dl'('pl'r di\c for tell to t\\'('lIty l11illll!l'S. \Vith ('aeh lln'alh, t\\'() hlo\\'s, Olle fmlll each Ilostril, an' \-i\ihl(, to a IlI'i~!tt of I to . ..., III

ahm e tIlt' auimal. .-\lthollgh they lllay lllake lleep di\('\, EII/m/l/t' /Ill are 1I0t heli cved to dive as dceply as othl'r species of \fy~lat'()cdi,

1'.\II\Slll':S : It \\'as fOrllll'riy 1H'lil'\'"e1 that this \jlf' l' i.·s 11 :111 a \ :lril'l y of ('\k1'll;11 parasitl's, [II rcccllt Sllldics, how('vcr, tholl .~h t\\'o speci('s of a parasi I ic \\'hale lic(~ Wl're fOil lid a \I o\'('r thc body, t hne \\'IT(! 110 acorn barnacles or ship harnacles. Black right whales silllply do lIot lIli,t:r:lt<' illto \varm water wherc the lar\'ac of these barnacles arc alllllld:!llt.

\hsn:Lu:-,;!-:Ot 'S: The "'"~th.wcight rclatiou,ship is as follows:·

C(lperea

Some char 3c.

l. Size sf] ceti) .

2. Dorsal :3. Four fl -1. Bod\' ' . .." :\0 Ill»)

C (I /ie n 'll 111111'

I-' i ,~II rc~ l-:l. Co in 1,'-\ 113,

\ f, III 1'1 IO U ICY

of I he follo\\ togdlwr, t hI' projl'dl'd ill

T"i~ is tIll 6 Ill. [n th()s, ho(h- is hht'l a side, arc l ('cI~'" TllI'rl' app('~lr I)f(m i,,, aho"t 011("

GCllef(J[ Biology 13

n' ldy II", i'.J ht l.olytl, (EI<'/Ildill!l 11/"" ,/ ,,,,,I f,·N.,)

----------------------~------------- -------------F lI . i:\1 :\1 l-!. -I F 1·1. 1 :\[ 1l.7 :\l 15.1 :\1 lli . l :\l li . O :\1 17 . 1

t ·! .s 'it;k l.j ~~.~'7 Iti . ~tili 51 .H·!ti j .), '! .1-' \i5.tj!}1)

OJ.7.jlJ Iii . I !.Ii

-----------------------------------------Caperea

Some characteristics of Cape rca are the following: 3c.

1. Size small, less than 6 m in body length ( slllalle~t of the \[ystaco-ceti .

2. Dorsal fin pn·St'nt, flip[l( ' rs slliall. 3. Four fingers ill flippers.

-I. Body color entirely black. :J. ~o bonnets.

CaperCll /lwrgillllia

Figllrc 1-.1. ("fI/II ' rcn m "';.:illfl tn. kllown .I~ It", P\ .~'lly ri.\.!ht wh .dl·, 1I.lml'd by Gray in 1IW3.

\fOHPliOlOC,Y: This s[l('ci("; i~ placl'd ill II\(' family Ih1.\(·niciae I)('callse of the follnwillt; ('hara ·t( ·ristics: tl\(' S('\TII ('en'iell \"( ' rt(·hr:H' are all fllsed

tog('thN. thcre are 110 throat grom·(·s. the Illaxillary alld pn ·maxiJlary arc prnj('ctccl in all arch ~llap/" alld tIll' hall '('11 i~ "1I1~ ill rl ·J. d i' lI l to its width,

Tllis is till' 'llI ;t1I,· , t III tIll' \I~ \t.lf'llcdi. n·;II..:hilig a 11I;\\illlllll1 kngth of

6 m. In those' sJ)('cillJ('m of ",hi('h tIll' hody cillor ha\ I lI " '1l (!f.~cril)('d, the

hody is hlack \\'Ith a pal<' ahdomen. TI}(' bal('('11 plat(·s , 1I111111lf'ring 2:10 on a side, arc palp yellowish whill' \\itlt a hrowlI frill~e alol1''': the e:-;tc'rior edge. Then·fore, \\,~l('n tl\(' row is ()h.~('r\"(·d olllsid." tIll' baleen plates

appear hrowlI in color. 'I'll!' l'y('s app('ar hl ;·ck. 'I'll(' cOll (kl() hasal I('ngth

is aho"t olle-fourth I)f tl\(· total hody lell .~th ~ J 2:3 to !I)() Ull ill Olle sped-

Mammals of the Sell

men) .. \Ithou~h a sternum is believed to exist, none has yet bl'cn describcd. The ( 11r 'at fill is about 1.5 cm high. The vertebrae are presumahly C7 -;- Tl7 + L:2 + Ca1-l-15 = 40-H. Seventeen pairs of ribs are attached

to se\enteen dorsal (or thoracic) \·ertebr~le. Altho Idl the internal organs of this species have not yet been studied

extensi\'dy, thl' skelton indicates a rebti\'ely large mass of intern,ll organs. In a 3.3 m specimen, the small intestine was 40 m long, twelve times the body length. The same specimen had a 1.7 m large intestine and unlike

most It't:lceans, a ~o cm cecum.

DISTIIIBl"TIO:'l1: This species is limited to the sOllthe rn hemisphere. Speci­mens 11.I\e bee II reported washed onto beaches in Australia, ~e\V Zl'aland, South .-\ frica , and South America.

FA~IILY ESCIIHICIITIID,\E

SOHl(' characteristics of Esduichtiidae are the following: 2b.

1. ~l) \cntrai grooves, but 2 to 4 furrows of skin are visible on the thro;lt.

,J I kid Icn~th comprises one-fourth to onc-fifth of total bodv ICllgth. :3. \L!\illae, premaxillae, and vOlller ,.;\i'-!htly clln'cd forward ..

-I. H.tlc('n plates, yellowish \ ... hitl', thick alld short; t -IO to 11)0 plates ,'n ~l side.

::>. \"0 dorsal fin, bllt sevcral hUlllps situ;ltcd on dorsal surface of thl' t.tii 'itock.

6. F,lIlr fingers ill flipper. 7. ~1'\'L'n L'('rvicai vertehr:w all Sl'paratl·ll.

This f.ltllily has ollly one gClllIS, alld that ~I'IIIlS consists of hilt OIH' specie,. t.sl'hrichtiw; giblJOsrts, fOlllld at prewnt ollly ill the ~orth Pacific.

E,~c"ric1ltirt.'I

Eschrit'htirt" gihboSlls

Figllrl' I-I, J-:s('''ri('''tir(.~ gihlJlJw.I', knowlI as the Ctliforn i,l gray \\hale. Ilalllt'd hv Enlcll< '1l ill t 777.

~ 10Hl'IIOLOC

the B,lbeni(

1.5.0 rn, but but the J\'C

arolinJ the is gra~ ' , (br

The propl

this spccies

T 'IC m~l\il LI ' of IhLil'nilL

fifteen ~llLl II chaiIl of IHI to the luse

tip-tn-tip tli ' \Iost CUlll

aloll~ thl' t , to thl' !lipp(' from thL' ~1l 1

Sl':lrs allll til are ; d~() :d 1\

The IIp[lt'

is li~ht \( , 111)

Tili, 'llnil's IUL':ll<'d .It t '

ho It,. Thl'H' jll~t pl),lt-ri o <In' Oilly ,Ii ~

forlll a cird, Thl' ;lIltlit,)r

the aIllcril)r o Ill' C ~1I1 pI! t hi~hDt Plllt with the ,1[1

Thc t, l\ I \!" (' is ~('IIt ' r~dl~ ' lT rLlill ;\1'1';1

;IPlw,lrs 'i~1 TI It' (Ii p p'

l' lIce ill c,li l

Th:lt dilil-rl c;lIl'icd 'n' ;

ph , tl;III~~:;tl I

Gener111 Biolog.y 15

~IOfiPIlOLOCY: In appt'arance, the genus Eschnchtius is midway behn.'en the Balaenilbe and Batll'lloptericbe. The hugest female CH'r recorded was 15.0 m, but the average is 12.7 m. The largest Ill,de recorded was 1.5.:3 m, but the ;l\'erage is 12.2 Ill. In both male and female, the girth is largest around the b,lse of the Hippers ,mel decreases towards the tail. The body is gray, dark gray or blueish gray.

The proportion ot head to hody length is rebtiH'ly :;mall. The skull of this species is wider than Babenid'ae bllt narro\\"('r than Balaenopteridae, The maxillary projects forward with less of a d l)WII\\'ard curve than that of Babenicbt' .. -\Ithough there is no dorsal fin , there is a chain of se\'en to fifteen small bumps on the dorsllm of the last olle-third of the hody. This chain Ilf bumps starts arollnd the intersection of the allllS and continues to the base of the tail flukes. The tail flukes are of interlllediate size, the tip-to-tip distance reaching one-fourth of the body length.

\(ost eOllll1Hlllk two hut sometimes fOllr, !!roo\'t~s ahollt 1..5 In 1011" run , ~ '"

aloll" the thro;tt parallel to the body axis. The half of the hody postl"rior to the flippers is llllitc rough allli is usually co\cred with injmies aud scars frolll tht' a1lilll ;Ii 's ruhhi1lg against s,ulll, rock. ,1I111 other ohjects. Those sears and the h,tkl'l1 plates are often con'red \\'ith hamaclcs. \\"hale licc are also ;dltllldallt.

The IIpplT j.lw has i·IO to ii)() haleell platl'S Ull (';tclt side. The Ilalel'1l is li!!ht ~"('lI()\\i,1t whit!', ·to to ;")0 Clll IOIl~ alld h;l.' \I'r~' nlllgh, thick I>ristks. This species has 1l1allY tadile hairs (IllO[(' th~1ll .\ll~' other Sp('cil'S of wh.d') located at til<' IIp[ll'r alld lower jaws ;111d OIl thl' forcll<'ad Ilear the hlow­hole. There ,tn' 110 hlllllps at the haw of these h,lirs. The ('Yl'S arc locat('d jll!>t posterior til the a11gk of .~ap{' alld are ()\'al ill ,hape. The lIpper eyelids arc Ollly sli<.!htly longer thall the lo,,"er lids. \\'rillkl"s ah()\"(~ ('aelt ('yelid forlll a circle arolllHI the eye. This Illay he dill' to th(' shape of th(' skllll. The allditory o[ll.'lIings are locakd ahollt lIlit!\\';IY l>t't,,"(,l'll the e}'l's alld the alltnior illscrtioll of th(' flippers. TIl<' op(,lIill~ is large el101I ,ld, ihat OIH' call pllt ,I p(,llcil illto it. Th(, hhJ\\·llOlcs are loctted slightly Ill'hilld the hi!!lH'st portion of the rostrlllll. The two holes forlll 'iOlllcwhat of a \' shape with the apl'x ill till' a11t('rior amI till' opel! portion at the posterior ('lid. Th(' tOIl~IIl" is narrow, thick, alld sallllon-pink with ;1 gray tip. TIll' 1>11I1>1)('r is !.!"llerally 1.3 til 20 Clll thick hilt may re~leh :>.') em ill thickl1('sS ov('r certaill areas of the hody. I t is IIsllally \'pry li'.!ht y,,"m .... hilt SOIlH'tillH'S ;1]>1)(";lr, li<.!ht pillk .

The flipper has fom lingers, of tell id(,lltifiahl,' from (lIltsid(, hy a diff('r­('Ill (' ill color Iwl\\ '('('11 the skill OUT thl' fillger hOlll's allll tIll' :;kill het\\"('('Il . That differclI('(' ill'ikil! color is Ilatmal ill SOI11(, illdiYidlials, hilt is often causcd hy aiJrasioll of thl' fi11ger parts. 'fI\(' first fingtT docs Ilot ('xbt. The phalall'.!eal fornllrla is II: .1, Ill: .1, rv: ,1 alld \': l. The u-rtchral formula

16 .'lllIllTlla[s of tile Sea

is C7 + Tl-! -i- Ll2 + Ct:!3 = .56. The seven cenical vertehrae are all separated. The first, second, and eighth to fourteenth pairs of ribs arc Ilni­cuspid ( sing le headed) and the third to se\'enth pairs arc hicuspid. The pel\'ic hones are relati\'eJy large.

DISTIlIUCTIO:\": There are two groups of EschrichtiiJ~le in the .'\orth Pacific: one which JI1igrates along the Pacific coast of :\'orth :\merica and a smaller pOPlllation which makes seasonal migrations in the western "'orth Pacific.

~rICH,\T[():X : .\cconling to past observations llIade in I\:o['('a, tIll' grollp in the western :\'orth Pacific migrates southward alllllg the coast of I\:orea from late :\'()\cmiJer throllgh late Janllary. They ,Ippear in the w,llers off Uisan cv<' ry year after :'oJ()\,cmoer 20, incre,lse rapidly to a peak in Decem­ber, and then hegin to 1lI00'C out , completely dis:lppearing hy late Janllary.

The sOllthward migrants can be di\'ided into three grollps. The earliest "rollP appears ill bte :\'oH'1Il0er throllgh mid-Janllary and cOllsists mainly of pregnant females. The second grollp, coming in pods of sen ' ral non­pregnant females in the company of twenty to thirty males. increases to a ma\imulII in late Decemher and thell disappears in mid-January. The thinl gro1lp. the illllll;ltllfl' mall's, IIsllall) less than 11..5 III in I<-lIgth, appears in the waters of Ulsall in early :\'o\('llJl>('r thrclllgh bl<' Janllary. TIll'S!' illlllJatnre males aI" not a large percelltage of the POPlllatiOll amI pre­slllnahly lIIi~rat(· simply to anlid th(' cold waters of tlH' ~orth . . \ltho1lgh tIl(' migratiolls of this population are lIot w('11 kllmnl fnrtl\('r sOllth thall Vlsan, it is IH'Ii('wd that they lIIay hrl'ed ill the \\',\I('rs north of th e Goto Islafl(l~, S01lth of l\:yush1l, or \\'('st to the Clwj1l.do bLind. Th(·y may not Inigrate as far ~outh as Hy1lkY11.

The Ilorthward migratioll takes plac<' 1>('1\\'('('11 \l.lrch allli \Iay. Dming this tillH', pods cOl11powd of ollly s('\('ral whak, begin til follow paths further off shore than th(, paths of tIl(' sOlltlwrIl migratioll ill s('arch of th(' ahllllllallt food of tl1l' l1()rtIH:m :\orth Pacific. Il1di\ idllals t'lltl'r the Okhotsk Sea in Jllne and then migrate fmther into the :\Ielltian watns. 111 the past, this sp('cies pass I'd throllgh thc waters off tIll' ('ast coast of Japan, alld catch('s wcre record('d ahmg the ('ast coasts of ")'IIshll alld Shikoku. in the arc;1 of \\'akayallla. In recellt Y(' :lrs. IUI\\·(·\'(·r. tlll'rC' has 1)('( ' 11 110 n 'cord of captnr(' or ohs('r\'atioll of this ~p .... ci('s off til(' cast coast

of Japan. TIl<' / ';ro;lt-rn P:lcific pop"latioll rnigrah's alolH~ thl' coast of :\orth :\m!'rica

ill hit, 1)('( (·"d)('r ,IIHI J;l1l1lar~ . ani\ ill!.! ill alllllHl. llll 'c alllll>..!; tlu ' CalirflJ'llia p(,lIill~ula ( Baja Calilornia) and the ClIlf of Cali\ofllia ill Janllary throll~h \ larch. D1IriJl~ th(' sIlIlIh\\'ard 11li.!.!ratioll, tIll' \;\1111' thn'(' distilH'ti\(' S('g­

re 'ations which ('\i~t in the wat('rs off "orc'a nla~' hc ohs('r\('d ill this population. This indicates that the sOllthward migration is a hn'(·din ,~

I migration. 1 and calm c ~ lagoons and

tide. The nortl:

The animals

then crOSS t of this speci assumed thn and then en further thral through Sep

AnC:\"D--'.:XCE :

were the firs exploited e~d to shore duri to catch. Tit Pacific.

E\tensin' around 1. des t royed.

earlier. gra in LIte \lar

to late \Ia~

R EPfl()[)1(

are clow 0

dnrin<:! tlw on'" If) to

prcgnati(lll mon t hs.

BEll \ \ ' [011 :

hel\\('('n sl

Gelleral Biology 17

migration. The animals parturate and nurse the jll\eniles in the lagoons and calm coastal seas. Some animals are left on the beach (in shalIow lagoons and bays) during the ebb tide and return to the sca during high

tide. The northward migration t,lkes place in late Febm'lry to carly April.

The animals move along the coast as far north as \'JnCOl\ver Island and then cross the Gulf of Alaska towards the Aleutian chain. The passage of this species thro\lgh the eastern Aleutian Islands is not recorded. It is assumed that they 1ll0H' \\"(:'srn',rrd south of the chain JS far w('st as 180 0

and then enter the Bering Sea, where they feed. Sume appear to go on further through the Bering Strait into the Arctic Sea and spend late June through S€'ptcmber there.

ABU1I:o.-\:-;CE: This species was once \'er~' abundant ill coastal waters. They were the first whales to be sought hy the Anwrie:lll \\'haling ships :1Ilt! wcre exploited extcnsively by the coastal nativcs both bcC':ulse of their proximity to shor ' during lIli"r:ltion and because they are pWh.lhly the (':lsiest species to catch. The abundance of gray whales was reduct.'d first in the castcm Pacific.

Extensin' whalill" of the gray whales I)('gan off the east ('oast of Korea arollnd 1900, an(1 in twcnty years, th' western pnplIl.Itioll W,lS ,t1so nearly destroy('d. The Internatiollal \\'haling COl1\'cntioll p [ ( hihit(·d the slall~hkr of this species. (I1!'c!'lItly Ih(, Ullited States CO\crn!1Il'lIt grantcd perlllis­sion for the capture of a hundred gray whales c.lcll year to dctl'rlllillc whetlH'r fmtlil'r protectioll is IItTt'ssary.) .\llIeric:lIl ,d!'lItists cmrt'lltly estimatc the stocks along the Pacific coast of .-\lIleriLl .It 9,000.

Foon: eray whales reporte(lIy takc no food durill,:! thl·ir southward migra­tion hut f('cd cOllstalltly dming tli' nort\twanl mi '..!r'ltion. As disclIssed ('arlin. gray \\·halt·s P,ISS throllgh the waters olf l"!,.11I goillg lIorthward in late \[arch to \1:1Y, alld olf the ('astern coasts of Siheria in Iatc .\pril to latc \lay. sp('lIdill~ some time ill the waters off the west coast of Sak~ haHn ami ll()kbi(lo. III additioll to copqJOds. tll<",· \\·hal(·s pn'sllIllably feed on Il!'rrill!,! ('~~S alld scho()lin~ fishes alld SOIlI(' s('a ClICIIlIllll'rs have l)('en recordcd f Will :-. tOlllach COli ten ts.

REI'HOI) 'CTIO:-;: Durill'.! their southward migration. ;111 tli(' prt'gnant whales are c1osC' to c\l'lin'ry ( fl'tllsC's arC' :3 to ·l III in 1('II~th . On thC' otlH'r hand. dllrill~ tlj(' 111lrthw.ml migratioll. all tIl!' pn ' .~II , \lJt \\ h.d"s ha\(' fdll~('s of only 10 to .10 ern ill Icngtll. This indicat('s that the partmition and im­pregnatioll arc pt'aked ill l·'(,lmlary. amI that '..!(' -;t.ltion is ahont twelve months.

BEII.\\'[On: Gray whalt's hi ow three to five tillws in f.tirl~ · rapid succession hetween shallow di\('s and then may make a longer, decper di\'c (per-

18 ~[(/l1Im(/ls of the Sea

haps 100 III in depth and 1000 m in distance) of s('n'ntt'l'tl to eightcl'n minutes' duratioll. \VIlL'1I the}" are making shallow din's. thl'ir flukes do not hreak the \Yater, but when they are dhing deep, tlleir flukcs cOllie out high in the air. Gray whales' lIsual s\\imming speed is 3 to -! knots but they may reach 7 to 8 knots when fleeing.

When the blow is observed from behind, the \'apor colulllIl from the two blowholes is loosely separated, though not completely distiIlct as is the case with the right whale. When obsen'cd from the side, only one blow is distingllishable.

F,U([LY 13:\L.\£:,\OPTElIlD,\£

Some dlaractcristics of Balaenopteridae are the following: 2c.

1. Ventral grooves prcsent. :2. Head length less than one-fourth of hody length.

3. ~raxil1ae hroad alld do not cur\'c strongl~· with premilxillae alld vomer.

-t. flaleen plates short compared to hrcadth; morc than ~oo haleclI plates Oil each side.

. 5. Dorsal fin presl'nt. 6. Four fingers ill ilippl'r. I. Sl'\"ell cl'rYical vertchrae all '1"l) ;ILlll'd.

This family includes the most ahulldant of the haleen ",hal(·s, .\lthollgh halal'noptC'fids are foulld in all occallS, tl\(' lIorthern pOPlllations do 1I0t illt 'rlllillgl, with southern poplllatiollS hlC~IIlS(' of th!' llalf-Yl'ar lag ill Sl'a­SOliS h,twcclI thl' northertl and s()lIthl"rt1 hl'\IIisphl'fl's.

The hody color \';ui<,s among 'pecil's awl ill<li\'iduals. Balal'lIopteridal' Ita\'e a Jarg(' 1lIlIlIh('r of short, wide Ilal( '('11 platf'S. Thc skllll has a /lat, wid(' 'II01lt, alld the l1Ialldihks an' \\ ' id,'I~' '('[);Iratcd, forlllillg a Iar~(' III!Hlth. T ,II!' paric·tal hOIlC l'xtcllds as far forw,ml as the SlItl\fC behillc\ tl\(' \lasal hClIll~, Th!' frontal hOlle dc)('s lIot c'xll-lld . I~ far hack as tit!' top of ,tIl!' cra­lIilllll. The occipital \'011(' extc'lIds forw;ml h('yolld the orflital fossa as far as the S([llaIlHl,.;al bOIH'. TI\(' ca\ity 1)11 tIl(' slIffac!' of the sqllalllosal l)(lIl!' is c1(·I·p. The rihs forlll all arch a~ tlwy joill the trallS\l.'rsl' proCl'SS of tIl<' \('rtcbrac·. Two gellera arc illcllld( 'd ill this falllily: Balaelloptcra ali<I \ I ('gaptcra.

Ba I (/( ' /III pf e ra

SOllie characteristics of HallII'II01lil'fli .Ir(' tll<' follo\\"i Ilg: .la.

1. "(,Iltral grooves ilIon' thall forty ' l:Ollnt betw('cn f1ipP('rs), :) Flippn lcllgth I('s~ thall OIH'-'('\("lIth of I)()dy length.

BalaenopterlJ

Figure 1-5. B( in 1758.

Ba1aenopte Sa.

1. Ventra , 6a.

2. ~forc

7a . 3.

to w('igh s

('stimatcJ

deck of a

sectioning, lotal wcight. relation het Y aX", wh to each spec III the case c f(dlo\\ill~

TIll' IlOdv on the dors from the ('alkd \\hit(

n a e It

a .e is

'n

~b at ';1-

ae (h' th o 'ial ra-far '11('

ht' 11(\

General Biology 19

Balaenoptera musculus

------ - - ----_._---

Figure 1-5. Balaenoptera musculus, known as the blue whale, named by Linll.leus in 1758.

Balaenoptera musculus also have these characteristics: Sa.

1. Ventral grooves reach na\cl. 6a.

2. More than 300 haleen plates. 1a.

3. Baleen plates all hlack.

(}rl/E..:R Co~I~lOS NA~IES: Sibbalu's rorCJllal, ~eat whale.

\fOHPIlOLOCY: The hllll' whale is tIlt' iarg('st animal that has e\"t'r exist('d on earth. According to thc International \Vhaling statistics, the largest ever reconlcd was a 31 m female takcll fwm the Antarctic Ocean. The lar~cst 111 ale, also taken from the :\ntan:tic, was .10 III long. It has heen impo.~siblc to weigh sllch a large hody: therefore. the total weights have heen estimated hy weighing individllally the parts of the hody. separatell on the deck of a whaling factory ship, and later totaling thcIn. Since sllch a totaling does not incillde SOllie of the blood allll hody fluid lost during scctioning. that slim is increased hy \0 to 1:3 per cent to estimate the total weight. A specimcn 2-U III weighed Rl ,OOO kg hy this mcthod. The relation hctwcC'n wei!!:ht alJ(l length is represented hy the eClllation Y - aX", wh('r ' Y is hody w('i~ht. X is hody 1(,Il~th, a is a constant (specific to each species), and b is a codficil'nt ( variable aCl.:ordillg to hOlly shape) . [n the case of this spccies the length-weight relation is representcd hy thc following

Y(t (\.()() I.') 1 X (f(·(·t :0:'

The hody is sax(' hlile with 'llIlH' spJashc(\ pattl'rtls forlllcd hy pale spots Oil the dorsal skill . SOllie allimals han' whit(' lIecks Oil the wntral grooves frolll thc rear margin toward the thorax. SOll1e also i1ave \vhite strip<'s. called white patch('s, across tht' axis n('ar the aIlUS, arollnd tile .~cnital

20 )of (lIllIllU/S of tile Sea

opening. or around the tlippers. The undersurfaces of the flippers ano flukes arc ;llso saxe blut', and there is a radiant pattern of pale color, callcd striation, on the lower surface of the tail flukes. The color of this pattern varies with individuals and with stocks and is considered genotypic. Al­though these patterns tend to fade out as the animal ages, striations may be used to identify different stocks of whales.

The Hippers are relatively small, reaching only one-eighth to one-seventh of the body length. The dorsal fin is shorter than that of the fin whale or sei whale. The baleen plates, induding the filaments, are all black and are as much as 90 to 110 cm long ,lnd .50 to 60 ern wide. The mammary gLmds lie J.long the ventral axis on either sitle of the ~enital slit. During lactation, each gland may he :2 m long, 60 em wide, and 30 cm thick.

A \vide maxillary (e\'en at the tip) is characteristic of the skull. This wide upper jaw is quite apparent when swinlllling hlue whales are o!JsL'rn,d from above. Generally, there is no vcstige of the femur on the pekic hone. The sternum is small bllt strong, and the hlade of scapula is large. The \"ertebral formula is C7 + T1.5 T Lt.5 + Cal~:27 = 6:~-l. The llippcrs have four fingNs, ano the phalangeal formula is 1: -l (-h'5), II: 7 ( .5-8, LV: 6 (5-7), and V: -l (:3-1).

D,STlIlUUTIO:-.1 .\:-;\) \hCI\ATIO:-:: Blue whales arc found in the North Pacific, ~()rth Atlantic, Antarctic Ocean, dc. Those in the northern hemisphere are shorter than those in the :\ntm:tic Sea (hy approximately 1..5 III at the same a~e). Ilowe\"('r , there is IHl .1[lparl'I1t racial difference among thelTl . There is no exchange of populations hdween the northern and southern hemispheres. The population in the southern hemisphere extends fro1l1 the warm waters near the eCl'lator. where the animals migrate in the fall for breeding, to the vicinity of the packed icc arollnd Antarctic, where tlt('y lIIO\e tlmil\g the slimmer.

The population in tht' northern h('misplwre is found in hoth tlte ,\tlantic allli Pacific, the Atlantic populatioll \"L'ntming as far north as ' the drifting ice and the Pacific population ('xtcnding as far north as the Alelltian chain, tho1\gh not into the ncrillg Sea.

;\nc';D .. \:'-;CE: Since the heginning of :\on\"('~ian whaling, hlue whales havc hcen t'"\tensi\"cly exploited .. \s a n'Slllt of Fars of o\"('rkilling, the stocks of this sp('ci(' "~ in tIl(' ,\lItarctic Ol,(, ~lll Ita\".' (ktTl'a\('d gwatly to the PfI 'Wllt population of only 20,()()U to .)() ,()OO anilllals . The stock size in the :\'orth Pacific is estimated as I.()O() to 1,.')()O. TI1<' pop"latioll in th(· Atlantic is \"('ry small, prohahly no lIIore than "')00.

FOOD: nlue whales seem to be \"cry se\ec;ti\"e feeders, preferring sl11all cllphallsiids. Their distrihution is limited to the watcrs where ellphallsiitis ,Ire ahl\ndant. Small fish that arc s011letimes fOl1nd in the stomach contents are proiJahly swal1o\\'l'd illcidclltally dming feeding.

in Decem eight more n

It was onc age determi I years. Curre reach maturi

BEH.-\VIOR: ~ ,

LO:-.1CEVITY: I

ninety years \

PARASITES: ~

and ba rnacl bntsh-like cr these, )'ellO\ which have affected arc found in the skin.

V ARIATIO:'-;S: whale, Baiae

Balaenoptert"

Figure l-n" HI

7b. Ba 11lL' 1/ opt

with one thi

OTlIEII CO:'.I

MOIII'IIOU )C "

male and fl Antarctic 01

GClleral Biolo!;.!! 21

.REPRODUCTION: In the southern hemisphere. Bnlae/lOll/em /IIl/SCUlflS hreed in temperate seas during July and August. .\£ter ten to e1en'n mOllths of pregnancy, they retum to these seas for parturition. The new?orn are 7 to 8 m in length. Lact~lting mother whales with ju .... eniles are often observed in December and J~Ulu'Hy. The lactation period presumably lasts for six to eight more months and the mother can be impregnated for the next winter.

It was once believed, using cemmen (ear plug) counting as a hasis for age determination, that blue whales re,lclwd sexual maturity in 8 to 10 years. Current evidence suggests :2.'3 to :10 years is more accurate. Females reach maturity at approximately :2.'3.-1 m. males at :22.6 rn.

BEHAVIOR: The blO\vs reach as high as 10 to 15 m.

LONGEVITY: Studies 011 c('nllllCll indicate that this species lives to about ninety years and rarely over one hundred years.

PARASITES: ~fost of tht' ('xtt'mal parasiks ,HC crustacea, mainly whale licc and barnacles. These apparelltly may also propa~ate Oil the skin. A paint­brush-like crustacea called p('1I11l'1Ia is also ,I l'OllllllOn skin parasite. Besides these, yellow laycrs of diatoms arc of tell found owr the skin of whales which have SpCllt the \\linter ill tIll' north,·rn ~orth Pacific. Allimals so affected are callcd slllphur bottoms. \'l'lllatodl's alld Cl'~todl'S ,Ire sometimes found in the digest in: system. alld cy~ts qf u'stodes art' fOllnd under th skin.

VARL-\TIO:-;S: Ichihara (L8fm) propml·tl ,l'i aqlhsp<'cics the pygmy hlnc whale, Balaenop/crll /I/llsell IllS l)n'l: iC{/f/(/Il.

Balaenoptera pili/salliS

Fignrc 1-0. lill/W'If ' /I/('f(1 /'/"/,11/11-', 1..110\\' 11 ." thl' fill "h.dl', 11"1111'" by Linnacll~ ill 17 .),~ .

7b.

}311"/I'''(I/I/I'((/ /lIIIIWllis ha\ (. IJaI''l'1l platl'S \\ hich arc mainly hluish gray with one third of th(, forepart 011 the ri~ht ~idl' hcing )Tllowish white.

OTIIER CO\I\IO:-; ~.\\IES: Fillhack, COlllmOIl rorqual.

~fOlll>lI()U}CY: According to the fllll'TIlatiollal "'hall: statistics, tIl!' lar~('st male and fClllail' ('\Tr callght W('f(' hoth 26.S III specimens takcll ill tl\l' Antarctic Occall. Femall.san·ragel t).7ITland.l11al(.s tn.'=> m.

,\lammals of the Sea

The dorsal surface is hrownish blaek, hding gradually bllt irregularly into white on the ahdomen. Some animals appear yellow to green because of the diatoms which may ding to the outer layer of skin. Two dark areas are clearly visible, passing from the vicinity of the flippers toward the grooves. Another black stripe runs from the middle of the tail to the anus. On the back, behind the blowholes, at a plane nmning through the inter­section of the base of the Hippers, a V-shaped pattern of lighter color expands bachvard. A stripe of pale to white color nins back and upwards from the external ear opening on each side. The upper jaw is symmetric in color (except on the baleen plates), but the lower jaw is black on the left side and white on the right. "hen obsen'ed from the outside, the left baleen plates are blueish-gray, while the front one-half to one-third of the right baleen plates is yellowish-white. All the bristles are brownish-gray. The largest plates are 70 to 90 em long. The average number of baleen plates varies from 3.50 to 360. A pair of mammillae is located at the inguinal region but is generally hidden in the mammillary valeculae.

The skull is fairly fiat, though not as fiat as that of the blue whalc, and the mouth is large . The flippers are short, rcaching only one-elcventh of the total body length. The fluke is less than one-fourth of hody length. The small but \ery distinctive dorsal fin is positioned on the dorsum at the lcvel of the anus. The eyes, lo<:atcd ahO\·c ;\nd behind the corner of the mouth, arc sIIlal1. Two hI ow holes arc located on the axis of the dorsal surface a little in frollt of thc plane of the eyes. There are from fifty to one hundred tactile hairs growing on hoth the UpPI'f amI low('r jaws, and there is a distinct clump of hairs at the tip of the lowcr jaws. Fifty to sixty ventral groon:s run as far hack as the navel.

The vertehral formula is C7 + T1.5 + LU-16 + Ca:2.5-27 = 6Q-..{).1. The maxillaries arc nearly as wide as those of the hlue whale. The blade of the scapula is well developed and the flipper has four fingers of I: 4, II: 7, IV: 7, and V: 4.

DISTIHIIUTIO:-;: Fin whales inhahit all oceans hilt are not found in coastal waters. The largest pOPlllation is in the Antarctic. ,In the :\forth Pacific th('y may he sccn in tIll' BCTin .~ Sea and Arctic Oce,ul.

~rlr.I\ATIO:-; .\:-;0 Allc ... · I).\:-;<:F. : The fin whales gencrally migrate to areas of colder water in the Sllmll1('r for feeding and to wamwr seas in the winter for hr('(·ding. TIll' pn'wnt .\ntardic populatiol1 is (·\tilllat!'<1 at SO.OOO. TIH'Y are less ahundant ill tIl(' northern hl'lIlisplH're, with approximately lS,OOO living in the ~ortlt Pacific and S.OOO ill til· 'mth Atlantic.

FOOD: Fin \\'haks, particlllarly in the .\ntardic Ocean, an' fond of sllch sma 11 crustacea ns as ell pha usiids, C (/{(JTI/IS, and .\Iljsis. Fish fOllnd in the ~tomach contents Illay SlllIldilllCS hc swallowed accidentally. hilt in the

newborn Juveniles a'

BEHAVIOH:

of about 6, be visible; the whale m) of abo its Aukes

This spe reason, it \ boats of to over thirty and the bo. whale will so far Ollt c the chase I: and its crll~

for Stich lor

LONGEVITY .

ninety to 01

PARASITES:

ship barnac injuries. T lamprey III

characteris cestodes in under the s

r-. (ISCELL\-';

through th steel tuhe ' an 18 mm r the animal recorded a member cc

Gelleral Biology 2:3

North Pacific, fin whales have been reported to feed 01\ the srnall pelagic fishes such as herring, mackerel, saury, and tomcod, and l'H'1\ on squids.

REPRODUCTIO:-.l: Fin whales are generally considered to he monogamolls and much affectionate behavior has been obserwd. They migrate to polar waters for feeding in summer and then rehlrn to the lower latihlde in winter for parhlrition. Pregnancy lasts t'le\'en to hvelve 1110nths, and the newborn are about 6.4 m in both northern and sOllthern hemispheres. Juveniles attain sexual maturity in eight to ten ye;,us.

BEHAVIOR: When they are, making shallow dh'es, fin whales take a breath of about five seconds dmation every two to three minutes. The blow may be visible as high as 6 to 10 m. After making several of these short dives, the whale will m,lke a 10llger, deeper dive (probably no !,'Tcater than :200 m) of about fifteen minutes which it will hegin quietly without bringing its flukes out of the water.

This species is the fash'st and most acti,'c of the \lystacoceti. For that reason, it was seldom caught IJefore the dc\'('lllpment of the fast catcher boats of today. Even now, the catcher boats 1I111St follow the animal for over thirty minutes at a speed of 18 knots hefore the whale begins to tire and the boat can clllse within rangl'. As it is clused by the whaler, the fin whale will not hrillg its flukes Ollt of tl. > water, hut it may raise its head so far out of the water that the ,'entral grooves arc visihle to observers on the chase boats. Its maximum swimming speed is prohahly over :20 knots, and its cnlisillg speed about 8 knots. ~o other species of ,\'hale can swim for such long periods of til11e at slIch high spe(·ds.

LONCEViTY: Based Oil the study of cerumen, fin "'hales are assumed to live ninety to one hllndred years.

PARASITES: The external parasites include whale lice, penclla, acorn and ship barnacles, protozoa, and hacteria. all of which produce some surface injuries. The microorganisms often calise secondary i11fections on the lamprey marks. I (Prc, as with hllle whales, these illfections often leave characteristic ,,'hite scars, [lItC'rn .. 1 parasites include nematodcs and cestodes in the digestive system and cysts of parasites in the muscle or under the skin.

~hSCELL\:-;Eot ' S: The lIligratillll mlltl's of tlli ,~ sp('('il'~ an' \'C'ry wC'lI stlJ(li(·d throllgh the lise of markillg harpoolls, The marki11g harpoon is a stailll('ss steel tuhe \\lith a CClne- ,~hapl'(1 lH'ad that is filled with kad , It is shot from an 18 mill rillc at the dorsal or waist part of the whalc as the hoat approaches the animal. The date, location, C'stimated hody length, and spccies are recorded at the timc of th ' marking and these data arc pro\li(kd to all the member cOllntries of International \Vhaling COI\\,(,lItioll, The harpoolls

.'llllJlnlllis of the Sea

remain in the muscle or hlllbber and may later be reeon'reu if the whale

is killed.

VAlUATlO:-':S: As in the casC' of other species of ~[ystacoceti, fin whales in

the northern hemisphere are smaller by approximately 1.5 III at the age of sexual and physical maturity than those in the southern hemisphere, thollgh they are usually the same size at birth. On the cast long itude

whaling ground of the Antarac:tic Ocean, the :1\'eragc body size of fill whales increases from e ast to west while the \'it<Hl1in A content of the lin~ r

oil and the number of ontlations dec:rease. Recent studies han~ related these occurrences to \'ariatiolls in the food supply. In the stocks which inhabit the South China Sea and Yellow Sea, males attain sexual matllfity

at a length of 15.6 m, females at 17.8 Ill. [1\ other stocks in the nortlwrIl hemisphere, males attain sexllal maturity at 17..1 Ill, females at 18.6 m.

Ba[aenoptera edcni ,----=-=- - -. -, .. .

7e. Ra[aclloptera cc/t'lli call he distingllished hy their haleen plates which

arc a'll slate gra~ with dark-color('d hristl<·s.

~[OIlPIIOL(")cY: Both sexf'S of this species reach a maximllm siz(' of ahollt H.5 m, 1.5 m small('r than th(' S( ' i whale. The I1Ican kngths are 1:3 III for

ff'lTlaks and 12 m for males. Althollgh the hordC'r hetwc('n thc dark dor.~al and white ventral ,\urfac('s is ('\("n h·ss lIoticl'ahlt· ill Bryde's whale than ill the sci whale, till' hod~' colors of tIll'S!' t\m sp('ciC's an' g('llI'rally qllitC' similar. The innt'r Sllrfac(' of the flippers and tIl(> lIndl'rsllffacc of tIl<' tail

f1l1kes arc gray. TIll' dor.,al fill is lI1o(IPratl' ill size anel lH'ight. leans hack­wards, and r('s('mbl(·s that of fin \\"halr'i. Tht'fe arl' ahollt forty-fi\'(· vI'nlral groo\"(·s.

The baieclI platl'S are approximately .')0 ('Ill in 11'1I~th ,\Il(l short, rf'lati\'(' to width . TllI'f(' arl' ;lppro.\illlall'ly th n ·(· hllll(l«'d plates Oil each sidC' .. \11

intcrval hetween thl' I(·ft and right I'm\'>; of halccn plates exposcs a widr area of palatine. The Illaxillary and premaxillary do not Cllf\'(' dO\\'II\\';lrd hilt project forward rathn straightly. Th' corners of the mandihle extend

. . ~ ..

".) .

backward ,1ppears to 1:

A main ri

the blowhol

jaw on each tactile hairs are found in

The vertl

generally th

bicuspid. T~ 10 em deep teristic of thi

have a proll! 5, IV: 5, and

DISTIUBUTIO:"

Central Paci 400S and wi

are seldom f warm water

ABUNDA:-ICE:

mated, no in the migratior species and i ~

size may not I

FOOD: Althol

main fooo it mackerel, all

reporteo on Fraser (19.1(-j

REl'HODCCTH)

12 .. 5 m.

BEHAVIOH: B like tho.~e of three times I dcnse school

ohservcd ate

PAH:\SITES: l:

whale licc, (hookeo Cl'

freqllcnt illt( commonly f('

~.I.. • • _ ~

, ..

Gelleral Biology

backward beyond its joints. Its cross section is rounded bterally and appears to be thicker th;1II that of the sci whale.

A main ridge mns along the axis from the tip of the jaw to the center of the blowholes. This main ridge is Hanked on the outer surface of the upper jaw on each side by a subridge. The sei \vhale lacks these ridges. Se\'eral tactile hairs grow along the outside of those ridges. Other tactile hairs are found in the same locatiun as in other Balaenopteric1ae.

The vertebral formula is C7 + T13 + L13 + Call = 5~. There are generally thirteen, but sometillles fourteen, pairs of ribs. The first ribs are bicuspid. The groove which separates the two heads of each rib is ahout 10 cm deep and the shape of the two heads is very distillcth'e and charac­teristicof this species. The neural spines of the dorsal and lumbar \'l'rtchrae have a pronounced posterior. The Hipper have four fillgers of I: 6, n: 5, IV: 5, and V: 3. DISTRlB1.TIlON: Bryde's ",haIL's' distribution is limited to the North Pacific, Central Pacific, South ;\tlantic, amI Indian Oceans. between -to"N and 40°5 and within arcas \\' here tIll' water temperature is over 2.0 ' C. They are seldom found in the watcrs of higher latitude, exCt'pt where there arc warm water projections.

ABU:-lD:\:-;CE: Although the presellt le .... e1 of population has Ilot ht'pn esti­mated, no indication of declilling population has l){'l'n presented. lIowe\'(~r, the migration of this whale is not as extensi .... e as those hy sOllle other species and is confined to a smaller o\'t'rall area; thus, the world pop"latioll size may not he large.

FOOD: Although this species lIlay ft'(,d Oil small plallktollic Crustacea. t hl' main food items seclll to he stlliid and slIch pelagic fishes as sardille, mackerel, and saury. They are also fond of sam.! Ianccrs. Olsen (HJ 1:3) reported on a spet:inH'n that had patt"n a great nllmber of sharks, and Fraser ( 1936) rcported that a Bryde's whale fed on herring.

REPHODCC.'IO:-l: '\fales attain s('xllal maturity at U In and felllaics at 12.5m.

BEHAVIOR: Ulows arC' not high hilt gi\e the impression of heillg \ 'cry thick, like those of the fin wIJal('. Tht'~t· whaks generally .breathe only two or three times hetween decper lIIore prolonged dives. They often form a very dense school, with tt'n .~ of whales or sOllldimes O\'er a hundred llt'in1!; ohscrn'd at Ollt' sit!;htillt!;.

PAIIASITI:S: External para~itl'\ ill 'lllcle acorn aJl(1 ship harna<:\es. 1l<'llt'lIa. whale lice, and Hflfllt'llOlJ/'ifis IlIIi.\dIlS (on halct'11S) . .\fall)' Hofho\()/JI(J

(hooked cestodes) are fOllnel in the intl'stillt" hilt Ilolle of the mort' frequent internal parasites fOlilld in oth(,r spccies of Balacl10ptcridae are commonly r 'ported in this .~p('l:i(·s.

-~ .'[ammaLs of the Sea

Bnlaenopiera bonllercnsis 5b.

Figure 1-8. Balnelloptera bVl1aerensis, known as the !\ew Zealand piked whale. named by Durmeister in 1867.

Bnlaenoptera bonaeren.s'is can he uistinguished by the following charac­teristics: 6b.

l. Less than three hllnUred haleen plates. 2. Color of baleen platt's all yellowish white with grayish brown outer

margin.

OnlER Co~n(oN N .nIE: .\ntarctic minke whale.

MOHPIIOLOGY: The animals uf this species lack the white hand on the flippers that is a characteristic of the little piked whale. The maximum body length is about 10 m fur hoth St'xes. The hody is charcoal gray on the back and white on the ahdomen. The dorsal fin is distinct and tlH're arc ahout Sixty \'cntral groO\l'S that reach the na\'c\' The ha\cens arc vcry characteristic. Both anterior aou posterior portions are light yellow. Fmt the posterior balcens are ollso fringed on the ollter cdges with grayish I>rown. That fringe is " 'ide ill front and narrow in back. There arc 2.'50 plates on each side which fI';lch a maximllm length of 3.0 em.

J3fllllelloptem aClltoTOstTlitfl

hglll"f.' I-C), /ifl/IlIIII J/J/.-r/l •. fl / u m, lmlll. killtwil "\ the lilll.· pik .. d "h.d ... 1I.lIl1cd by Liu·'p':de in lElO·I.

The distingllishing charadt'ristics of nul(wTlOptera lIClltorostmta arc as follows:

1. Ventral gr

8a. 2. White ba 3. Baleen pl

OTHER CO~n.,(O

MORPHOLOGY: 1 largcst specimen mens over 9.2 n

kg. and the aver The body is

pOinted. The tot fourth of the b. located in the Ia: grooves betwee l as the navel.

The dorsal Sll surface is white whale. the hOllH a straight line. : bottom snrface black extending the flippt'rs is sk of each flipper. portion of tile I flippers. while it The haleen pial brown. The "hi side arc r('lati \C'

ba \cens, on the indi .... iduals is 1.5

The prnjet:lio species of this f of the wi whale at the hasc . TI l vertt-hra I fnnw

stnlllllli i'i n ' \;

cheHolI honl's,

~ft<:HYII():-'- ,\;\' 1)

the p()lJldatioll Sea alld fmthl'l

General Biology 27

5b. 1. Yentml grooves do not reach navel.

8a. 2. White band on the flippers. 3. Baleen plates yellowish white.

OrnER Cm.I~ION N .HIES: Lesser rorqual , minke whale, and little Bnner.

MORPHOLOGY: This species is the sm.lllest of the Balaenopteridae. The largest specimen reported was 10.:2 II1 in length. In Japanese waters, speci­mens over 9.2 rn are rarely found. The maximum weight is about 10,000 kg, and the average weight of .1Ilimals 8 III in length is about 6,000 kg.

The body is slender and spindle sh'lped. and the rostnlm is sharply pointed. The total spread of the tail fill kes (a long the axis) is almost one­fourth of the body length. The dors .ll fin is high, slightly blcate, and located in the last one-third of the body. Thcre are about sixty fine ventral groO\'es betwl'en the left and right flippers that do not reach as far haek as the navel.

The dorsal surface of the body is hhlck (often grayish) and the ventral surface is white. Unlike the irn'glllar pattern of thc sei whale or Bryde's whale, the houndary hetween the two colors of the piked whale is almost a straight line. The H'ntral side of the caudal [l<'ndunc\e is gray. TIll' bottom surface of th' tail lIukes is light gray to sky gray, fringed with black 'xtL'lHling from the lIpp<'r surbn' of the flukes. The illside surface' of the flippers is sky gray. A hand of white color rUlls across the outer smbn' of each Hipper. The houndary betwl'('n this white hand ,lnd the hlack portion of the hack of the hody is \Try distinct along the hase of tlJ(' flippers, while it turns gradllally illto dark ~ray near the ('nd of the Hipper. The haleen plates ar' yellowish white alld sometimes fringed with dark brown. The whih' hri:-.tl(·s of the approximately 2.'-)0 to .100 haleens on each side arc relatin'ly fiJle. The piked "hales of the Atlantic Ocean ha\'c ilion' bal('ens, on the aw-rage. than thow of the Pacific. The higgest halccn of indi\ 'idllals is [,'5 to 30 cm long and .'5 to 12 em wide.

Till' projectioll of tIl(' maxillary and maJl(lihlr! is 1I0t so marked as in other spel'il's of this family. The llIaxillary i\ ('\'1'11 sharp('r :It the end than that of the sei whale and is widencd toward thf' iw;idf! (or tow:lrd prcmaxillary) :It the haSf'. This indicatr·s that the n;\sal c\\'ily is \arg(' and wid(' . TIll' wrkhr:t\ fllTllIl lIa i, C 7 . Til - 1.12 ,- (;;1 17- JI) - I() ( ·17 - ·I()) . TIll'

stl'nl1ll11 is [(·Iatively Iar~(' and noss ~hap(·d. Ther<' arc! gencrally II'n th('\ ron hOlll's .

~lrclI\TI():\" ,\:\"1> .\JlI:-.;n\:\,II·:: I)lITill~ tIll! spring tllrllligh SIIJllmCT months,

the poplliation IlI'ar Japan lIli~ra\c's in ("oastal waters north illto the Bering Sea and fmtlH'r tllTOlI ,gll tIll' Ikring Strait intn the Arctic Ocean. Thollgh

:28 .\lnmnllll~ vf tl/(' SI'It

this species IS not so coastal as the gray whale, imli\'idu,\ls do frequent coastal waters and are often accidentally c,\IIght by Japanese coastal set nets. During the alltllmn and winter, the retllrn migration southward follows a path further off shore. Groups arc small and segregated into mature and immature individuals. Immature specimens, particularly imJlla­ture males, do not migrate extensin'ly into cold waters. Females tend to venture further into colder \vaters than clo the males.

The migration of this species nC,lr I\7orway is very similar to that ohseryecl near Japan. There, piked whales migrate north along ~orway coming close to the border of the C.S.S.R. The :'\forwcgian \\'h,\lers hunted them arollnd Rear £Sland and SpitzlX'rgen in the Arctic Ocean, hutchering the whales ahoard the boats.

:\lthollgh distrihution in I he sou I hem hemisphere has not becn stud ied, information ohtained in the :\orth P,\cifie indic,ltes that those found ill the iced sea of the Antarctic Ocean are prohahly mature females. This ~pccics goes further into iced was than allY other species and has he('n ohsl'nnl extending tht, head \erlicaHy to hreallll' through holes or cracks in Ihe iel'.

Despite an annual catch of :3,000 to :3,.300 animals hy ;'>,'orwegian whakrs, the ;\orth .-\tlantic populatioll has not decreased. The total pO[lllbtioll is eSlimated as .30,000 to 70,0()O \\·hales. The Pacific stock is Illilch 'lila lin, prohably totalling only ahout to.()O() Wh'I\cS.

FOOl>; English scicntists r('porte(l that piked whales in thc ~orth St',\ fl'd on the ahlllldallt hl'rrill~. jOllsganl i H).')£) n'portl'd Ihat illdi\idllals of this specics distrihllted I\('ar thl' :\or\\<'gian coasts fecd mostly Oil fish. while those fOlllld ill tIll' .\r<.:tic Ocean fCl'd on ellphausiids. Those fl)lIlld ncar Japall also haH~ a wide selcctioll of food incllldin.g I'lIphallsiid~. l'ope­pods, ('a lar III s, sardilH's. ~alld Iallcers. cod, po \Jacks, atka mackere\. s,lllry, mackerel, alld squid.

Ih:l'lIoJ)CCTIO:-'; (n Ihe :\orth Pacific, Im'l'diIl~ occms ill Fehruary Ihnl1l~h April aJl(1 partllritioJls occllr in Jallllary throll .t.:h ~Iay aftn a pr('~llallcy of t('11 to elev('11 Illonths. The:' IIC\\'!JOrJl arc :2.11 10.'3.0 m lout::. alld lactalioll Ia~ts about six lIIonths. :\ stlldy of 11)(' .t.:rIlwth <:lIn'(' of f('(lIsf's illdicall's that the peak of tIll' br('edillg wasoll is ill C,lr!y ~Iarch. ~lalt's attaiIl s('xual maturity at fiJ) to I.t m. females at 7.:3 Ill. (II this rcspect, there is \'('ry little dilrerellcl~ h<'l\\'('('11 .\llalllic alld Pacific ~rollp.S .

JOIIs,t.:ard (1D.31) J'/'porll'd Ih.t! f'·IIl.tll· piked whal,·s ill III(' .\ILlillic al n;lgl' (HI(' hirth pIT YI ·. Ir. OIl)lIl'a \ It).)()) reported Ihat Ihose l\(';lr Jap.1I1

gin' OIH' hirth pl'r I or \' ~ years. Tllis rate of l'C'prodllction is hi~h('f Ihall that inmost otll('r sp<'l'il's 01 \Iysta('()cdi.

BEIIAV!OIl; Although hlows [('ach oIlly ahout 2 III in Iwight. Ihey apP(\\f large relative to hody .~izc . TIll'S!' \\·h.dl·s 'tay OIl Ihe snrfacc for SC\ eral

seconds be Their maxi and their n

V A1UA TIO~S;

and Pacific ide'ntical, th their maxim other hand, slightly mor notch of thl animals. :\It. skull, there warrant estal

I Balaeno/lterl

I

, I , ..

Figure I-ill . I

BalaellOpt 8b.

1. :\0\\1 2. B;dcl'

OTIIEH CO:\

whale, J"pa

~ f ( Jill' IIOI.()C

statislics an call.~ht rt'lT '

The ItorS extends fair which fade .' inner smLi(

General Biology :29

seconds between shallow di\es, each of which lasts for five to seYen minutes. Their maximum swimming velocity is 10 to 15 knots (or to 24 krn/ hr) and their normal speed is 9 to 11 km/ hr.

VARIATIONS: Some racial difference is assumed to exist between Atlantic and Pacific stocks. Although the body colors of the two stocks are ~early identical, the average size of the Atlantic animals is 0.2 to 0.6 m larger, and their maximum size 1.:2 III longer, than those of tIll' Pacific animals. On the other hand, in animals from the Pacific stock, the dorsal fin is higher and slightly more anterior, the tail flukes are wider, and tJle distance from the notch of the flukes to the center of the allUS is shorter than in Atlantic animals. Although a fcw scientist:-; have reported some differences in the skuU, there appears to b' too little variation between these two b>LOUPS to warrant establishing a subspecies.

Balaenoptera bor('alis

Balllello/Jtera /Jor(,lIlis C.lll 1)(' di ... tin~lIishl'd hy the fo\lowillg: ' Sh.

1. No whit(' hand ()Il tht' Ilippt·rs. 2. flakell pLitt ·s all hLlck \\ ith fillt' whitc hristl('~.

OTIIER Co\nlo:-; ~ . \\l ES: Bildolphi"s rorqllal, lIorthern rorqllal, polbck whale, Japan fillll!'r . and .... trClill(· \\Ilall' .

~rOI\I'II()I.()CY : TIll' I)i .~~f · ~ t .~ci \ddt·s rt 'conh-tl in the International \\'halt' statistics arc an IS .. ) III Ill.tle and a :20 III felllale. lIow(,H'r, tht' Iar~(".;t

caught recently an: \,j t() ](j III ill I('n~th. The dorsal sid(! is dark-chocolate colored, hut the dorsal coloration

exte'nds fairly \\.( . \1 (Jlltf) till' ;Ihdorllillal sid('. The' transitional part is .!!;ray which fades with a wavy hOlllldary into the white of tIle ventral side. TIt(, inner surface of tIll' ffipP('r'i ;111<1 IIIHIl'rsmLic(' of tlte tail IIl1kes arc .~ra~' .

30 -'(amma's of the Sea

Th . dorsal fin j,s r btively large, high, and triangl 12I' in shape and ntcnds bachvard. The s: ze of tht:' flipper relative to the body is smaller than in other balaenopteriids.

The species has sixty to sixty-five ventral grooves with some individual variations. The longest baleen plate is about 65 em in length and :25 em wide. The number of baleens varies from 300 to -mo, with an average of 320 to 3-10. The t~lctile hairs are much less abundant than in the other species of this family. Those present grow near the external nasal openings on the outer surface of the upper jaw and on both sides and the tip of the lower jaw. The n~rtebral fonnula is C7 + T14 +- L13 +Ca22-23 = .56-57. The flippers ha\-e fOllr fingers of I: 3.-4, II: 5-7, 1\-: -1-6, and V: 2-3.

DISTRlliUTIO:-i _-\...'1> \hCR.-\TION: Sei whales are found in the North Pacific, North Atlantic, and Antarctic Ocean. Almost all of the sei whales that inhabit the southern hemisphere migwte to high latitudes but are rarely seen as far as the \-icinity of packed ice. \Vhalers h;lye hegull to concentrate on sei whales since the decline in abundance of blue whales and fiu whales. During migration. sc\-eral whales form a herd, but herds as large as one hundred whale s ~1I(, sometimes ohscrn'd in the South Pacific.

AUUNDA="CE: In the North Pacific, ncar ]'lpan. this species is the lllost abundant of the \Iystacoeti. Though approximatcly .j()() to L,OOO sci \vhales are caught evcry year, th('re appcars to ha\"(~ he('n 110 measurahle decrease in the population size. The catch in the ~orth .\tb(ltic is Icss suhstantial, and since the immature whales are very small and rarely callght, the population r('ductioll in that area docs not appear to be seriolls. ~o estilllate of the Atlantic p"plliation is availahl(,.

FO()J)s: Sei whales prefer small cfllstacea like C(JlmlflS and l'lIphausiids hilt also feed on sand lancers, herrings, cou, pollack. saury. sar<iilH's, etc. (As

the Japanese Clllll1110n name illdicates, fwashi-Kujira llIeans "sardine whale.") The fcod is widely \'ar:('d, hilt docs lIot illcillde hcnthic animals.

HEPnOm; c.TIO'o; : Li kc the other ha lacllopteri ids. ~l'i whales hreed and parturate in til{' tl'lJIperat( ' seas. Thl' hreeding season ap[wars to OeCllr from Janllary to \I;]rt'! ~ ill tl](' IllJrllH'1 II hC'llIisplH'f(' a!ld ,i\ !I10Ilth .... late]" ill tIl(' southern hl'mi:-.piH'r('. SC'xlJally matJlrC' males appear to mate with 01]('

female amI lin' \\i:lt I\('r dmillg olle hre('dillg S(";\'illll. Tlw nact location of hreeding gn)l !;lds i .... still ullknowlI. Youllg are l..5 toU) III at hirth. Lactation lasts for ~t1)()lIt six llIollths.

Both sex('s ap~)(, ~ lr to attain sexual matlIrity at ahout eight years of age when, in the northl'rn }H'mi_sphcrc, the male is a\)(lut 1:3,.) Tn ill 1t'lIgth alia the females are ;lhollt U..l rn. Animals in the ~()tJthl'rn h('misphere arc larger hy 0.9 III at the time of sexlJalmatmity.

!ff:W:

General Biology 31

BEHAVIOR: The bJo"'s are similar to, but neither as high nor as thick as, those of fin whales. This species swims very fast and may be able to attain a maximum swimming velocity of 30 knots (or .30 J..m 'hr) for a short time. Howe\'er, they tire very rapidly.

LONGEVITY: To date, no sei whates over seventy years old have been found. Thus the longevity of this species is shorter than that of blue or fin whales.

PARASITES: External p.uasites are quite similar to those on other species of Mystacoceti. Balaenophilus unisetus propagate on the baleen plates, and when those plates are removed from the whale, its development can be observed under the microscope.

Megaptera

The genus Megaptera was named by Gray in 1,C,6-t Its members can be distinguished by the following characteristics: 4b.

1. Ventral groO\'es less than :30 (count between f:!i~)l-"<.'rs). 2. Flipper length more than one-fourth of body len~th. 3. Color of baleen plates all blackish hrown \\-ith <brk colored bristles.

A-I egaptera not"(Jcanglille

Figure 1-11. .\f(,~l/ptt ril 1I0f'(1I'(lIIgli(w, \..:1]1)\\'11 as tl,.. I. ' . ;: lu ck whale, named by Borowski ill 17& 1.

MonPIIOLO<:Y: Accurding to the International \\"h,tlin~ statistics, the largest animals taken \\"t'[(~ a 19.0 III female and li.S III null'. I [owcver, at present, even fully grown females hardly reach IS m and nules are even smaller. There arc I.=) to :20 \entral groov(,s, each allll()~t 1,) em in width, reaching

32 ,"al/lmals of th(' Sea

to the navel. Therefore, this species can be identified simply by the ventral surface. The dorsal fin is relatively small and is located slightly behind the intersection of the anus.

There are two rows of sen'ral humps, each supporting one t~lctile hair, on (~ach side of the upper jaw. Oll each side of the mouth then' are 350 to 370 haleen plates, the external edges of which are usually less than 80 em long. The Hippers are quite long, reaching about one-third of the total body length. On the anterior edge of the flippers, there are serrations which appear to be related with the joints and ends of finger bones. The posterior edge of tail flukes normally contains notches.

The dorsum is black and the abdomen is white. The distance the black color extends down the side of the body varies from individllal to individual and is believed to be a genetic characteristic. Some of the northern whales ha\'e no white portion. The outer surfaces of the flippers are generally hlack, with this black color sometimes extending (in \'arious dq .. Tfees) to the white inner surface of the Hippers.

One humpback whale caught off Kyuquot, on the west coast of Van­COllyer Island, Canada, in July, 1919, had re'ar legs of 1.2 m in lcngth (in which was found a Done O.S 111 IOllg). One of these legs W:1S cut off hy a worker, hut the other has 1)('e11 preservcd at the ~ nited States ~atiol1al

~[uset\ln in \Vashingtol1, D. C. The vertebral formllla is C7 +- Tl-t + LlO + Ca21-22 = .=)2-.=):3. Thc Hip­

pcrs h,.l\'C four fingers of I: 2. 1[: 7, IV: 6, and V: 3.

DISTHIBL'TIOX: In the' sOllthern hcmisphere, hlllllphack whales are distrib­uted sOllth of the cquatorial zOlle to the packed-ice line and ill thc northern hemisphere north of the ('(lllatorial zonc to ahout 70 N.

\fICHATlO:-\, ,\:\D :\lIl':\D.\:\CF:: In JlIly through Septcmher, they arc found ill :\ lelltian waters ",line food is ahulldant. Some may ellter the .. \ rdic S('a yia the Bering Strait hut most arc distrihllted along the A Iplltian Island chain. Therc '"seems to be SOIlle' S('~r<'gatioll accor'ding to ;'Iatmity, In September and Octohpr, they start a sOlltlm"ard migration alld arC' COIl1-

lTIollly sc('n n('ar IIawaii and th(' \lidway Islands, Their distrihlltioll in Octoher throl1~h D('c(,l11l)('r i'i 1IIlkll()\\"Jl, hilt · it appears that t h('y l>rt't'd ill \\'aters of HP to 20:\, III early Jallllary. a part of tIl<' stock mi,gratcs rwar Okinawa and Ogasa\\'ara, This \11i,~ration is led hy i III ilia tllr<' llJaks, followed by th(' main gnHlp of paired mature males all(t felllales, th('n hy some inllllatllr<' f('mates alld a f(,w irlJlllatlire mall's. The last grollp is the lactating females aec()rnpallyill~ YOllng, They a\oid th(' Kllroshio l'Irrrcllt that nms off east of Taiwan, tllrns to the east at tll(' \H'St ('nd of Okinawa. and ~()es along the east coast of Japall. hecause it i.'i ;1 c1ear-wat('r Cllrrellt and a poor source of food, III tho..,(' years whell tire,,· 1\:1I1'Oshio currellt is

strong, the \\'hales migrate far ishore alld are rarely caught ne;.\[ the coa~t of Japan. Similar pattenls of m:_ ation are observed in the t',btem P:1cillc,

In the southern hemisphere. migration occurs primarily in the south­north direction. Therefore, the population in each section of the .-\ntarctic Ocean mllst he e\'aluatec1 illde~ndently from the others. The toLl' of all populations may be 10,000 to 1.5.000 whales.

BElL-\VIOR: In days when American whaling was prominent. several characteristic swimming beha\ iors of this species were describell as breaching, rolling, £inning, loht:liling, and scooping. On submerging for a deep dive, humpbacks almost always throw the large flukes high into the air. The duration of the more pr longed din's is fifteen to twenty minlltes. The blows are quite characteristic. being wide, relative to height. The brge flippers provide this whale \\'ith better than a\'crage undcf\vatcr mancu­verability.

FOOD: The main food items :lre pbnktonic Crustacea. Cod, lmt not p('tl~ic fish such as sardine, saury, or nuckerd han~ heen reported ,1S food. Also. Fraser ( 1937) reported that one specimen had eaten six sea birds. P!/([lacro­cra:c cap illllt us. The birds can prohahly he regarded as foreign ing(·stia.

REPnor)tiCTlOX: The rate of rcpr luctioll is comparatin·ly high. Prl'~llancy appears to last for ten to ele\ en months, and the female is hred again almost immediately after partllfitidll. The newhorn arp ,L3 to .~,() III :lnd at the time' of w('aning, \\'hich oc rs at lip to ten months of age. the y!lllll,~ hUInphack is 8 to ~ III ill lellgth, CpOll attaining st':Xual Illatllfity the II1:11(·s arc 11.1 to 11A m, amI the fe'lll.l!cs arc 11A to 12.0 m.

Suborder Odontoccti

Odontoccti call he distillglli,ht d by the foIlO\\'illg: lb.

1. Ollter openillg of nostril is ~ingle. ,., Teeth an' pn'sC'lIt. :3. Baleen plates are ahsellt. ' .. Profile of "Plwr sllrLtCl' li ,1\1111 (Jllaillly 1lI<l\illae amI pn·III.I\iILH')

IS concave . . "). StefllllIll is c!llllparatin'ly hrg(' (lIslIally segmC'llted) ;lIHI sk"ktal

COllstrtlctioll of l\t()ra\ i" I. lllpld('.

Odolltocdi ha\'(' ollly !lIlt' 1'\' ,T llal ll;lsal opelling, the two lI.h.d ca\'iti<'s joillillg together at the e\knl.ll l'lId fOfllling olle lIostril. Gcnerally, the lllollth is small alld lIarrow ;lIld contaills tecth throllghollt life. [n SOIlH'

species, the teeth arc developt'd ollly in males and do not protntde from the glllll in fCIll:i1I·S. OIl(' SPl.'Cil·' It:lS ollly olle pair of tedh (III the Imver

~------ -

Mammals of the Sea

jaw while some species h;.l\'e O\'er fi fty-five teeth on each side of both upper and lower jaws. Tooth number and size are quite variable and are thus very useful in classification.

The skull is asymmetric. The degree of fusions of cervical vertebrae varies, some species having seven separate cervical vertebrae and other species having all seven bones hlsed together. In contrast to the ~lysta­coceti, Odontoceti have large sternums. They lack a cecum.

The foreleg or Hipper always has five fingers, but the number of bones in each finger varies by species. This characteristic might be used in classification but is not widely used at present because the finger bones ,ue rather hard to examine and there is some intraspccific variation. Although the rear legs are not present, a trace of the femur has been observed in some species.

The larger species seem to have wider areas of distribution. Generally, they do not remain in one area hut make extensive south-north feeding migrations following favorable water temperatures. There are a few rare species (sllch as those of Platanistidae) which only inhabit specific rivers.

The breeding s('ason in the lar,~er odontocctes is tholl ght to extend from late winter throughout spring. Some smaller species have two breeding seasons, one in spring and one in fall. Some Odontoceti form harems. ~lost species are also gregariolls and tens to thousands of animals often group to~ether to form one hig herd. '\fost species feed on slllall fishes and squids.

The following ten families are established: Physdcridae, Kog,iidac. Ziphiidae, .\lonodontidae, Plalltanistidae, Delphinidae, Orcacllidae, PllO­coellidae, Crampidac, and Glohicephalida('.

FA:\IILY PUYSETEHIDAE

.\lcmbcrs of the P/'lJsetc:ricllle family have the follmving gelleral charac­teristics: 9a.

L. Tip of I{)\\'('r jaw ('lIds an appreciahle distance behind foremost part of head.

:2. Lower t('dh flJnctional, hilt IIpp('r teeth f1Idimentan' and lIslIalh­fOlln<1 within thC' gUIll.

lOa . . 1. I [('ad massiH" olH'-fomth to one-third of hody kll~th , ,l. Blowh()le far forward . . '). FlIllctiolla I ted h largc', ('igh tc('n to twenty pa irs, COil fi Ilc·d to lowcr

jaw. o. Dorsal fin an ill-defined hump. 7. First <.:c rvi<.:aI \{'rtebra free, second to seventh ccn'ical vl')'khral '

fused.

Gelleral Bio!o£:y

This family consist of only one genus whi·h includ('s but 011(' spE'cies.

Physeter

The genus Physeter was named by Linn.lellS in 17.58.

Physeter catodol1

- . -- :: . -- ..;; .. ---:2=~==:=::==-=:"""':::=-==

Figure 1-11. Physcf('T cotoclo", knowlI as the 'i\ ' nu whale, lIarned by LinnaclIs in 1758.

OTIIER Co~nlOx :"J.\~(E: Cachalot.

MOIlPIiOLOGY: Th ' largest specimens reconk-d in the International \\'haling statistics are a 19 In male and a 17 m fCl1ule . However, at present the largest malt'S reach 16 .. 5 to 18.0 m, though IS III is rare. The females are even smaller at present reaching 11.-1 to 1:3.:2 T\l. Unlike the different Mystacoceti. there is very little local variation in size among sperm whales.

The morphology of this species is uniqlle from all others. The forehead of the skull forms a conca\'ity from which the flat maxillary projects forward. The. £' parts resemble a man's hand \\-ith its palm upward. On the top of the ~kllll, a wall composed of m<l\iILtry, frontal, squamosal, and occipital hOll e'S is projected vertically frol11 the exoccipital hon~. In the big hollow formed hy this crest, together with the maxillary, there is a case filled hy a unique tissue called speml.lceti. The right nasal cavity nms und er the case, turns upward at the tip of the maxillary, amI O[1<'llS

into the hlowhole, located at the tip of head. The left nasal cavity nllls to the left side of the case and joins the ri~ht Llvity jllst hdo[(' it r('aclws the hlmdwlf>. There' is a broad hlind sa<:k hehind the caSt' alld in front of the h()l1()\\" ni the skllll. Tht> fllllCtiOIlS of "'p{·rill .l<.:di arc yt't 11 II 1.. II O\V II , hut it may Ill' im·(lh-('d in tlJ(' H>ry d(>t'p diYillg of tll i) "'peci('s.

Side \ it 'ws Ilf the adlllt mal(' show a \Try brg<' head that compris(>s ahollt olle-third of tlip total hody length. III the female, the proportion of head to tht' t()t~tl hodylellgth is not as gr(,~lt. The nasal open,ing is slightly S shaped amI positiollPd toward the' left side. The low('r jaw is narro\\". In a spt.'<:irnl'I1 I.') 111 long, it was ahollt :20 <:111 wide at the front end and ahollt 70 un wiel(' Ilear the' <:OrJH'r of the month.

36 Mammals of the Sea

The teeth are conical in shape, oval in cross 5ection, and about 10 cm in diameter in adults. On tIlt' upper jaw, there are no exposed teeth. Instead. there are sockets into which the 10\\('r teeth fi t. The upper teeth, ten to sixteen in number, are usually wholly within tlle gum throughout life though on occ,\sion they are exposed at the sockets. F e tal sperm whalt's have many three-pointed teeth, a characteristic which may he reminiscent of Squalodon, generally consiuered the ancestor of Physeteridae.

The flippers are relatively short and round. \\"hen the animal is vicwed laterally, a big notch is visible at the point where the anus is located. A keel begins just behind the antiS and gradually narrO\vs toward the tail flukes. The dorsal fin consists of a chain of sm.111 humps along the dorsal ridge, the first of which is particularly distinct. The number of bumps varies with indhiduals.

The hody of spem1 whales is slate gray or <.Luk blucish gray, generally paler on the ah<.lomen. The skin around the mouth, especiaJly near the corners of the mouth, is particularly pale in color ,1I1d almost white. The anterior end of the body is some what Hat with white spots distrihuted in a spiral pattern. Some animals have a whitc ~ l ot on the nan'!. The illlH'r sllTface of the tIippers and understlrbce of the tail IIlIkes arc the same color as the body. Sperm whales are light in cnitlr when they are young. darken as they mature, and bcgin to fade as they grow old. ThereforC'. though \[ohy Dick, the great white whale of the famolls I\oH~ l, is fictional. seeing a large okl sperm whale makes the source of the legcnd 1I11<.1erstand­ahle. Thcre an' records of the capture of a pllfl' white sperm whale ncar Japan. hut en'n though the color of the c y('S W,iS lIot recorded. that animal is assullled to ha\'e l)('cn an alhino.

The \'('rtl'hral formula is C7 + Ttt + LS + c.t2-l = .SO. The first cerdcal vertehra is free hut articlllah's with the mass fnnlled hy the fusion of the next six cl'T\'ical \'('rtehrae. The first eight of the eleven pairs of rihs arc t\vo 11<'ad('(1. The last pair is \'('ry sJllall, eyen thollgh it is joined to the vcrtehr:le. The IIlJllhar \'('rtehr:H' arc q\lite thick and strong. Th('}"(' an' nine to ten calldal H'rtchrac hf'tw<.'('n the tail /lukes. Usually, the hasihyal and thyrohyal of the tonglle arc not fllsed. The sternulll cOllsists of two TOWS (' :wh of h,'() or thn'(' parts. It is df.,'('lop('d tn a ),!n ' :IIt'T ('.\kllt tlL11I ill

any othl'r sp('ci('~ of whall'. This lIlay hf' a fact'lr in the .~J"(·at d('('p-di\ ' ill~ c:lpahility of sperlll whal(·s . A \'( · sti .~ial f(,llIllr i, 'illllld il\\('s fOllnd. It lIlay articlllate witk (lr 1)(, fused to, til" lwh'ic hOlle, Thl' f1ipp('I' has fi\'(~ fillg('rs of I: 1, Il: ;), III: .S, IV: ,t, and V: :1.

The adl1lts lJa\e no hair. [n fact, at an early stage of dCH'lopmcnt in which the fetllSes of variolls porpoises still han' luirs, spe rm whale fdlls('s haH' already lo ... t all traces of hair. The mammary glands of the fcmal(, arc thick (aho\lt :2.3 to:30 em thick while laetatill!-! ' hilt narrow (ahollt .10 to

General BiologU 37

35 cm wide at the same p('riod) and may reach a length of L3 m. There is a pair of mammary openil1l1S located in the inguinal region.

DISTRIBUTION: Physeteridae occur hetween 70° and 70 C S.

r..hCR.-\TION '-\~D ABl;~D.-\"""CE: Because the body of a sperm whale floats on the sea sudace when the whale dies, catches of this whale were recorded even hundreds of years ago. During the eighteenth and nineteenth cenhlries, when American whaling was very acti\'e, a great number of spenn whales were caught in various oceans of the world and records of these catches, showing the distribution in those years, have heen well preserved.

The ranges of males and females are different. Females do not migrate into the cold waters but stay within -tOo latitude in both hemispheres. Because the gestation period is sixteen months and the hr<,eding season is quite long, there are always some pregnant females ill a group. Some bachelor groups, consisting of old males \vhieh are no longer sexually active, young males not yet sexually mature, and often e\"l..'n males at the peak of r<'production potential, are usually isolated from the others and migrate into the cold waters.

In the North Pacific, males migrate heyond the .\Icutiall chain into the Bering Sea, and catches have heen recorded as far as 60 N. \fales migrating to the cold \\'akr form the majority of animals caught by whalers and the catch of such a large numher of males might redllce the population size c\"('n thollgh thesc whales practice polygamy and ('xc('ss males are not ahle to participate in r<'prodl1ction. T{)milin (t~n.3) of the U.S.S.R stated that SP('flll whales do not migrate heyond Cape :\";I\·arin. ;\rseniev of the U.S.S.H. (UJ:3n) reported that they do not go lIorth of Olel1torskii Bay, and japalH'SC whaling boats ha\'c 1H..'v{'r taken sperm whales ncar the Bering Strait or in the Chllkchil Sea. The distriblltion in the ~orth .\t1antic has Ilot hc('n adecl'lately studied. hut sperm whales may hc distrihllt<,d as far Ilorth as 70 ~.

~TO sp<'rm whalt' marked ill the Ilorthern hemispherc has ('H'r hecn recaptureu ill the sOllthcrn hClllisphere and \'ice \('rsa. There is no estimate of thc populatiol\ size of tht' \\·odd. The ~orth Pacific population is ('\';dllat('d at 70,()()() tl) too.()Oo.

FOOl): Sperm \\'hales feed Oil squid hilt may afso ('at fish alld all ol'cd ... i()llal oct0PIIS. The sqllids includ(' hoth the smaller species and tIl<' giant squids. Squid hills found in the stolnach of sperm whales are often as larg(' as a chhd's head. Parts of giant squid estimated to he as large as 10 III ill )t'llgth ha\'c hcen H'('o\"('red from stOlllach cOJltents. Sm-kefs of tIl<' giant 'i(pliel lIJay )('a\"e scar marks of ;) to (j cm ill diametcr lIear thc mouth or 011 tIl(' Iwad of the whale~. :\ !though sperm whales seldom ('at 'illlall lwlagic fi.,ll<'s

38 :\fammals of the Sea

such as herring, mackerel. and sardine, they frequently eat demersal fishes such as cod or ocean perch. The capacity of the first stomach is 1 ~,~ drums (300 1), and more than half of the whales caught h;l\-e a full stomach.

In addition to these regular food items, sperm whales are known to ingest some exotic objects. At least one out of every 1,000 whales caught has its first stomach one-third filled with sand. Approximately the same numbers of whales have swallowed coconuts. Stomach contents may also include pieces of rock, wood, or worn, round stones. The whale may swallow these items accidentally while it is feeding on benthic animals. On one occasion, the discovery of a glove in a sperm whale's stomach gave rise to mmors that the whale had eaten a man and the glove was all that remained undigested. It is more likely, however, that the glove was Hoating in the open sea and was swallowed by the whale.

There have been no records of this species attacking human beings directly. On the contrary, a recent Life magazine photograph showed a SCUBA diver touching the tail llukes of a sperm whale.

REPHODl:CTIO;o.l: Sperm \V'hales are polygamous, and Juring the breeding season each breeding male has a harem. These harems are apparcntly formed during the off-whaling season, and for that reason, surveys of breeding behavior are difficult to cOllduct.

Sperm whales do not make any ('xtensh-e breeding mi!.!rations hut hreed during Jalluary thnHl·,h July at latitlldes Imver than -tll . In the northern hemisphere, the peak of the hreeding season is in April, and partllrition oceurs in July and :\llgllst after a 16-lllonth gestation period. The newhorn are ·1.0 to -1.5 m long_ Lactation lasts ahout 13 months. By the elld of lactation, the young may he as large as 6.7 m. :\t the timc they attain s('xl\al maturity, females are abol1t 8.9 m long and mall'S about 9.5 m long. Althol1gh males just r('adlillg sex11a1 maturity prodllce the same sperm as older ma],es, the YOllnger anilllals do not uSllal'ly participate ill reprodllction. On the other hand, £elll;} It'S hreed soon after b(,colllin~ sexually mature,_ and pregnant females S_7 to 9_0 m long are frequently found.

The age of Ollontocdi can uSllally he estimated from scctioncd tceth (~ishi\Vaki and Yagi. t9.'5-1). Using this method. it h~lS lH'l'1l d('t('nllined that both male-s and f(,lllall's aT(' 1Ii1l<' years old wllt-n tht'y ;lttain sexual matmity. Both continue to grow, howeH·r, and do llut attain physical maturity until th 'yare twenty-fom to twenty-fi\(' Yt';lrs (lId and tt III IOllg (females) Of twenty-nine y('ars old and V5.9 m long I males).

Bt-:II:\\'lon: \\'hell tIl(' arc _'iwirnming ncar the smface, sperm whales hreathe every two or thrce llIinutes. After a series of three to fi\-c shallow dives, they lH'gin a deep and illlprl'.'isi\"ely long di\"('. In the case of the large whales ( t.=5 m) of the Antarctic Ocean, this deep din' llIay last in excess

Gcru:ral Biology :39

of an hour. Several whalers have reported that diving sperm whall's have still not reappeared even after the whalers have waited for an hOl1r at the surface. Those animals near Japan rarely dive for such long periods (thirty to forty minutes maximum). The diving time of the female is generally shorter than that of the male, rarely reaching, and never exceeding thirty minutes. The height of the blow of a sperm whale is from 3 to 5 III and because of the position of the blowhole, projects forward from the head at an angle.

Two examples of cooperative protective behavior in sperm whales, though rarely encountered, are of interest. Zebras reportedly protect them­selves from attacking lions by fonning a radiant circle with their heads towards the center and kicking out at the approaching lions. A similar behavior occurred when, on a quiet day, a harpoon was shot into a school of twenty to thirty sperm whales. The whales fonned a radiant circle arollml the wounded, sl'apping the water with their tail Hukes. This defen­sive behavior, however, was an advantage to the whaler who was ahle to systematically harpoon the whales one by one. Sometimes, when the sea is calm, sperm whales may he seen sleeping while floating near the slIrface with the blowhole out of the water. They may he in a horizontal or upright position. On tlwse occasions, ,there are 1IS1Ia.1ly a few members of the group milling ncar them, apparentl'y on hrtlard for possible danger.

Unlike the baleell whales, which rarely attack boats. a harpooned sp('rm whale may charge evell the largest catcher hoat of today. ramming it with its head. If he hits the scww or rudder, he may disable the boat. In the early days of whaling. sllch attacks hy sperm whales often proved dcstrnc­tin.' to the' whalillg hoats and fatal to men. Drawin~s of whaling actidty durillg the eighteenth and lIillt('cnth centllfie's, when this specie's was the primary target of :\IIll'rican \vhalers , oft('n depicted spt'rm whales O\"('r­

tuming hoats and hiting or cnJshing thcm \\lith their tails. ~Iany of those drawilll''i wen' carn,d 011 sperm whale teeth, a forlll of art known as scrilllslwrc. .

Sperm wha!t's arc known 'to he deep divers. A cahle ship working off the coast of SOllth :\m<'fica (lis('ovcf('d a dead sperm \..,-halc entangled in a sllhmaritJ(' cahl(' which had b'('n s('t at a d('ptn of 1:200 Ill. TIl(' whale prollall\Y ' )('(allll' ellLlllglnl whil(' it was It'cd illg Ilcar the hottom. A silllilar illcidellt was reported on a ('ahl(~ hdw('('n Lisboll alld \f alaga wllich had hCt '1I set at a depth of 2200 m.

Sperm whales are often set'n playing on the ocean surfac('. AltholJgh they vcry seldolll jump completely Ollt of the watn, they often Plll1 half of th('ir body Ollt of thc water or throw the tail fillkt's high into tl)(, air. They also slap t/,I(' water surface with the flukes (lohtailing) or play with {loating ohjects sllch as logs or seaweed.

l' ).[ammals of till' Sea

LO~CE\"lTY: Sperm whales are belityed to live a maximum of seventy years.

P.\.R.-\SlTES: The most important external parasites are diatoms. Here, as with other whales, parasitic diatoms tend to drop off in warm waters. "'hale lice are found in some groups but arc not found at all in other'\. Penella often infect animals in \Lmn \\ atcrs but tend to drop ofF ill cold water. Barnacles of different species than those parasitic on ~Iystococ 'ti are also found. Large colonies of ship barnacles frequently occur on the skin and the tooth ridge. Anisllkis. a nematode genus, is the most common internal parasite, occurring in the digestive system, particularly the stomach. There are practically no \\'hales which are not infested with these nematodes. Parasitic cysts are n'rY common in the skin or blubher, but cestooes are relatively rare.

\II:'CELLA~EOUS: Abnormalities occur frequently. For example, ne:\r1~' olle

Ollt of every two thousand whales has a se\'erelv deformed twisted lown ~ ,

jaw that lllust be almost functionless, and many whales lack the tip of th . i:lukes or flippers. The attacks of sharks or killer whales are among the nuny possihle causes for such mutilations. Injuries sustained during the fights he tween sperm whales arc gcnerally shallow and le<\\'e lightly marked scars on the skin.

:\mhergris is a uniqlle sllhstance sOlndillles fOllnd ncar the ('nd of the Iar\.!e intestine and heginning of the rectllm of sperm whales. Analysis of a'l1hcrgris indicates that it contains many s(l'lid hills and other n'sidllals of food. Thcre arc two main sclwnls of thollght on the causes of alllhergris formation. The first theorizes that a IUIJl!1 of alllhergris is fOrll1l'd wh('n the whale is constipated for SOIlH' IInknown wason. The second liSe'S the foJl()win~ chain of logic: th' whales. particlllarly the adult males \\"ho are ('\I!..!;\ged in fighting among tll<'lllsch(·s. f(·(·d n'[~' little during tIl(' hr("l'dillg season. The reslIlt is that there is little feces and a residlle lIlay ITlIlain Ilndischarg'd ill~id(' the intcstinl' lIutil the \\'hales hegin fceding again in the spring. In some ill(.IividllaIs. that residlle lIlay not he passed evcn aft('f feeding [('SlIllles and relllaill~ as amhergris.

\\'hate\'cr the callses of amhcr~ris, its lise as a stahilizer ill 1>('("flllll('S ollce made it the most \"alllahle of ;111 whale' prodllcts. Advanccs in k("h .. Iltdtl, .. !s which n'slIll<-d in S\lItllt'ti~' .,r.t\lilil.(TS c;!II'icd tlJ(' yahit' (If \\ILd(· . . :11111)('rgris to wanc, hut [I'c('nt rc;dfIrlllati()n of its qllality has callSl'd a rise' ill its vallie. In U)():2, amhergris ~()ld at all a\('ra~e of SlOO pl'r kil'O\.!LIIII. The largest IlImp c\"(.·r reported \\'as all ('gg shaped mass, .=)0 Clll in diallld('r, \\'hich w('ighed (jO kg. ))('spitc the \\'id('spn'ad lwlid that all allllwrgris is alik(" the qllality actually \'aries ;\ g[('at deal. The \'allle of a gin'n filld is dctprrnined hy the analysis of ;\ '\lIIal1 portion of the IlImp.

General Biology

F.UOLY KOGllD.\E

Kogiidae ha H' the fol1o\\"i ng characteristics: lOb.

1. Head comprises one-sixth of total body length.

-11

2. Functional teeth small, slender, and curveo, nine to sixteen pairs confined to lower jaw.

3. Dorsal fin we11 de\·eloped. 4. All cervical vcrkhrae fused.

This family consists of a single genus, Kogia (Gray, 18-16), with t\\·o species of pygmy sperm whales. In the past, these whales were generally regarded as either a subfamily or as one genus unoer Physeteridae. How­ever, because of the many important differeIlces between the sperm whale and the pygmy sperm whales, the latter are tn'ated in this work as a separate family, Kogiidae.

Kogia

Some characteristics of the Kogia genus are the following: lIa.

1. Total body length of adult more than :2..~ m. (\Vcight IS more than 300 kg.).

:2. Dorsal fin l'ow and located posterior to cellter of hack. :J. Condylohasal Iellgth of skull more than :>'SO mm. 4. Tweh-e to sixteen (rarely ten or ell'n~n) pairs of mamlibular teeth . .3. \fandihlllar sympllysis long (S6 to I:W 111 III ) and ventrally keeled.

I\. Of.!. ill "rn: icc ps

Figmc [-IT ~ogi(/ IIfITinp\. ~II()\\"II .l~ IIH' P: gill:' ~p('nll whale. llamed h~.- lI1.lill\ illt' ill I ~.1H.

OTIIl':n CO\(\(I):"I: :\.'\11-: : I.('sser cachalot.

I 1 42 MammaL,; of the Sea

'MORPHOLOGY: The rostmm of this species projects forward in a triangular shape, and the mouth resembles that of a shark. The blowhole is slightly further anterior than in any other small odontocetes. There are no t('eth

in the upper jaw. Although there is some individual variation, the width of the skull re­

lative to the length is nearly 1 to 1. (In most odontocetes, the skull is much longer than it is wide.) The condylobasal length of an adult is be­tween 390 and -170 mm (approximately one-seventh of hody length). The dorsal cranial fossae are not cupped posteriorly, and the left fossa is con­spicuously longer and narrower than the right. The pterygoid-hasioccipital wings are elongated, and the foramen magnum is near the midpoint of the sk"ull height. Although both the maxillary and mandible are relatively short, the vomer at the middle of the skull is long, almost reaching to the tip of the mandible.

The falcate dorsal fin is located slightly posterior to the middle of the body and is quite low (approximatey 15 to 20 em in l1<:'i~ht). The Hippe'rs are fairly large, reaching approximately one-sixth of the hody length, and are sharply pointed at the end. The flukes, however, arc moderate in size, reaching a total spread of one-fifth the hody length.

The dorsal skin is charcoal to gray, and the skin of th" ahdomcn is ~ray to white. The transition of color from the hack to the abdomcn varies to a !,rreat extellt hetwecn individuals. From the external ('ar hackward, tlwr<.' is a zigzag-shaped white portion which also varies in patt('rn amol1~ individuals. The fiiplwrs arc slate gray, with the inside' surface slightly paler than the olltside surface. Both surfaces of th· tail flllkes arc gray or slate gray. S()me individuals have some cherry pink color Oil the ahdo­men and some hav(' hlueish color on the hack.

The hotly girth is greatest midway hetwecn the flipP('rs and thc dorsal fin. The camL.I portioll of the hody is compressed Y('rtically. Jllst hehind thc allIlS, the hody is twice as high as it is wide. The ahdominal ca\'ity is extraordinarily large, appearing to hc ahoHt twi<.:e the SIZ(' of dolph ills of comparahle sizt'o

The \'{'rtchral formula IS C7 + TI3 + 1..9 +- Ca:2.7 ,)6. The sev(,11 c('f\"ical \"('rtchLIt' are all fllsed togdlH'r. Ei~ht !lilt of tit!· thirt('('n pairs of rihs arc two h(';1<1('<I. Ther<' arc sevcntc(,11 chcvrolls. alld those ill tIl<' pos­terior part art' di\"id('d illto two, olle on each sid(' " TIll' st( 'rJIllJ1l is ill three pieccs alld is j()ill('d hy cartilage to four pairs of rill'i. Th('r<' is a 1I(,lIral spillc IIp to the thirt('('11 calldal \"('rtehrae and a trans\('r'i' process lip to the tenth calldal vcrtehrae. The flippers hav<' five fillg('rs of l: I, II: H, Ill: R, IV: 7, all(l V: .=), \\lith milch variatioll ill the 1I111111)('r of hOIH's. par­ti<.:lIlarly ill tht' f(lIlfth alld fifth digits. lIowever. sill<':(' few of the SP('CiIIlCIIS

General Biology

in the past haye been studied by x-ray, the bones might have been mixed up during collection.

DISTRIDUTIO:-; A~D .\BU~O.\NCE: This species is widely distrihuted and mixes freely with Kogia simlls. In the North Pacific, it is found in temperate and tropical waters. In the southern hemisphere, catches have been reported off Australia and New Zealand. In addition, there are records of stranded specimens from beaches of India, IndoChina, the .\tlantic coast of North America, France, Holland, and Hawaii. Because Kogia breviceps is rarely seen, the size of the world population is unknown.

FOOD: This species presumably prefers squid, but the stomach contents of a specimen found on a beach in France included coastal crab as well as squid beaks.

REPRODCCrION: Very little is known about reproduction in this species. A female about 3 m long beached in Holland during December of 192.1) reportedly had a 2.0 em fchls. An animal caught in Decemher 1924 re­portedly had a 22.5 em fetus.

Kogia simus

- ----~ --==--~--elM.,

-- .::::~ --

- - - - _ . Figllfc 1-1-&. Kngiil Sillll/S, known as Owen's pygmy~p< 'nn wh;dc, named by Owen in ISGE).

Kogia sinws have the following charactcristics: llh.

1. Total hody Ie II '.!;! h or adlllt less than :2 .. ) 111. , \\'eight IS I('ss than ,100 kg).

:J Dorsal fin high. IH'ar ('CIder of hack . . 1. Condylohasal lellgth of skull I('ss than ,jOO nllll .

. 1. Eight to elevell (ran'ly thirtc('n) pairs of nl.lndilHllar teeth. ,=5. ~lal1<.lihllbr sYlIlphysis short (:37 to 16 mm) ;llld ventral keel lacking.

\tOI\l'1I0LOCY: Except for the size and position of the dorsal fin and the total houy length, the gross appearance of this species clowly rf's(,ll1hlcs

44 Jlalllmah of the Sea

that of Kogia bredceps. TIll' dorsal fin is comparatively high antI is situated near the center of the back. The total body length is approximately 2.1 to 2.7 m in adults, slightly less than in Kogia brericeps.

The skull is proportionally smaller than in Kogia brcdceps. The condylo­basal length of the adults is between 260 and 300 mm (approximately one-eighth of the total body h'ngth). The dorsal cranbl fossae are cllPped posteriorly and are subsYIllll1etrical. The pterigoid-basioccipital wings are short, and the foramen magnum is well below the midpoint of the skull height. The width of the skull relative to length is nearly 1 to 1. There are usually three vestigial teeth in the UpPN jaw. The \'ertebral formula is C7.+ TI3 + L9 + Ca27 = 56. The seven cervical vertebrae are fused together and resemble three bones fused.

• ~ 1 •

DlsTIU~u:nO:'>l: \Vith the exception of body and skull characteristics. , Kogia breriCfips and Kogia simllS have not been studied separately. Therefore, it can only be assumed that the distribution of Kogia simlls is the same as that of Kogia bredceps.

F.\:\ULY ZIl'IIlIIHE

General characteristics of Ziphiidae are as follows: 9b.

1. Lower jaw extends at least to the tip of the snout. .J l3lowhole is some distance from tip of snollt.

12a. :3. Two conspicllolIS groo\"('s Oil the surface of the throat form a \' shape. -I. Dorsal fin prt'S<'llt, consi(h'rahly posterior to middle of hody . . "). ~otch of tail flukl's IIsllally "hallow or ahsent. 6. Anterior three or four C('[\'ical \'ertchrae fuscd.

The family Ziphiida(' is dh'id('d into fi\ 'e g(,Il('ra of "middll'-siz('d" whales (.5 to 1:2 III in length). Illdivid",ds arc characteristically spindle shaped. 11a\'e distinct rostrums, amI display V-shaped grooves Oil the \"entral sllrface in the throat regioll. The flipp('rs are gencrally small and slender amI Illay h(, three -times as long as they arc wide. The flukes are relatively large, measuring ahout one-fourth of the hody I<'ngth from tip to tip.

In ZiphiicLu'. tIl(' lIotch that i" lI'ilially pn'wllt at the C('IIt<-r of tIl!' pos­terior margin of the flllkes of odolltoct'tes is ahsent. extremely shallow, or replac 'd hy a slight projection. TIle tips of the IIlIkes arc pointed and cUr\'ed inward. The girth of the hody is greatest in the middle, and the dorsal fin is located cOllsid('rahly posteriorly.

Berardiu.'I

The genlls J3erarclills was named hy Dllvemoy in 18.:51. lts lllel1lhers can he distingllisJled hy the followill~ characteristics:

Gene ral Biology

13a. l. Two pairs of large teeth in the low('r jaw.

14a. () Adult hody length more than 10.0 m. 3. Second pair of teeth situated some distance from the first pair. -to No special protuberance on maxillae. 5. One to four cervical \'ertebrae fused.

Berarclius bllirdi

·~5

Figllf(' l-I,=>, lkrardills bairdi, l..n,)WIl ,IS 1I,lire!'.; 1H';lkl'd whalc, 1I;1I11l't1 hy Sll'jlll'gt'r in I~1'n.

Some additional charackristics of Ikmrdills lHlirdi arc the following: 15 ...

l. rnhahits only the northern h<'lllispit<'re, 2. COIJ(.lylohasal length ahout olle-eighth of hody length. 3. Total spread of tail flukes ahout one-fourth and lcll!.!th of Hipp r

ahollt one-elc\'cnth of hody length, r('spectiH,ly.

~IOIl1JIlOLO(;Y: The an'ra).!(' adult is I)('t\\'ccn 10.3 and 1l.1 Ill, though f('males f(';lch a m;txillllllll Icll!.!th (If 12.S 111 alld lIIales attain 12.0 Ill. Thl' hody is slatc gray, hilt thl' ahdolllinal side is slightly lighter. Senile in­dividuals have a f<,w white ,pots Oil t h(, H'ntral thorax or the ahdonJ('ll. The flippers and tail flukes are ahollt the samc color as the hack.

The hcad portion and rostrum ar<' f('latiH'ly long. Thc distance from the tip of the snollt to the corner of the mouth is abollt one-twelfth to one-thirteenth of the body length. The distance from the tip of the SIlOllt to the hlmvhole is ahollt olle-ei~hth of the hody 1('lIgth, The rostnlll1 reaches

-16 Mammals of the Sea

about one-sixteenth of the body length. The flippers h;lve a characteristic shape and reach onc-t'ighth to one-ninth of the hody length. The width of the fluke is ahout one-fourth of the hody length. The dorsal fin is tri­angular, hut the tip does not extend backward. On the surface of the throat, there ;ue grooves of about 60 cm in length. forming reverse V shapes. Often there ;lre small narrow grooves beside the major ones.

The teeth are trian~'1.dar in shape when viewed from the side and are slightly larger in males (90 mm) than in females (8.5 to 90 n1ln). The tel'th average about 70 to 75 mm in \vidth in both males and fenJ;l\t's. The den­tine is wry thin, amI the secondary pulp cavity is choked with osteo­dentine. The skull is almost symmetric. The crests of maxi Uary and frontal bones may be sc('n behind the nostril hut are not as high as in gen\ls Mesoplodon. The nostril is rOllnd but wide, and the preorbital fossa are distinct. The wrtebral formula is C7 + Tl{}-U + Ll2 + Ca17-19 = -16--19. The first to third cervical vertebrae arc fused . The sternum is COIll­

posed of five joints.

OISTJ\lBUTIO:-J: In the western North Pacific, this species ranges around the Kuril Islands and goes into the southern part of the Sea of Okhotsk. Individuals are ;llso found around the Bering Islands and in the Bering Sea, but arc not fOllnd north of the Dering Strait. On the American side of the Pacific they have heen recorded from Alaska to California.

~fICllA1l0:-J .\~D :\IIt;~D .\:'IICE: This species is second only to the "little piked whale" as the most important species for the Japancse coastal whalin~ industry. Land-hased whalers operating from various parts of Japan catch about 150 to 200 whales annually. Each year, the first catches on the Jap­anese Pacific Coast occur off the Boso Pt'ninsllla. Herds of whales ap­proach Japan from the southeast and turn to the north, staying vcry close to the peninsula ill \by and Jllne. Thereafter, the herds seem to continue northward, gradually dispersing, and reach the waters off Kinkazan in Jllne and August. They lIli~rate as far north as the waters off I [okkaido. SOllth­ern as well ;L~ northern lIligrants are ohserved simllltan{'ously from scouting airplan('s in the area of Sanriku and Ilokkaido during Septemher and Octoher. Judgill~ from the "size freqllency data" of eatclws, the pr<'S<'Il 't I ,\'('I of harH'st (Iol's not advcrsely affect the populatioll.

Foou: This ~p{'ci('s f('cds primarily on sqllids and hottom fisll('s . In addi­tion, the stomachs of some specimens havc contained such h(,llthic animals as asc:idialls, s('a l'1I{,III11!>crS, starfishes, and crahs.

nEI'ItCHln :TIO~: The growth rate is Ilot yet well known. hIlt lIIales attaill s('xllal matllrity at a length of about 9.:3 to 9.6 m ;1I1d fl'nla\('s at 10.0 to 10.1 m.

~ .

Breeding ap and the growth Pacific coasts of fetus ever col after birth was

waters in what hig male. Jlldgili by fishing boats

:'\1orma1ly-, the larger whales. prolonged (live 1 \\'hen they are hi misses one of thl" chalice. \VhcII tho Sea, the whales I

and frequently h

P .\J\.\SITES: The whale lice, pcn~

two of which lea and Onc!roccrcCl parasites are fou l \\'all of the ahdl

Ikrardills llTIIlJtjl Beraclills am

hy Duvcrnoy ill 15h.

1. Inhahits 2. Condyloh .1. Total spr

hody len

\fC)ItI'IIOLOCY: .­

/Join/i, tlH' 11(1[

sOllthern wllak flipp('rs, :lIld 11 ; of total in SOli

addition, til(' ~

hhl{! dorsal ski hody, and gra~

".

General Biology 47

Breeding apparently occurs between late Xovember and early ~Iay, and the growth cunoe of the fetuses of those anirrLlls collected near the Pacific coasts of Japan indicates that the peak is in Febmary. The largest fetus ever collected was -l.5 III long, and a young whale observed soon after birth was -l.7 m long.

BEHo\vIOR: Although Baird's heaked whales are gener~llly found in herds, lone individuals are sometimes seen. Near Japan, they appear in coastal waters in what may be harem groups of ten to thirty whales, led by one big male. Judging from the frequency of reports of observations of herds by fishing boats and scouting airplanes, this species is abundant.

Normally, the diving behavior of Baird's beaked whales is typical of larger whales. They will ll1<lke several shallow di,oes followed by a deep prolonged di"e of about twenty minutes. The blow is low and spread. 'Vhen they ano' harrassed, they may dive for over an hour, and if a whaler misses one of these animals, he may have a long wJ..it bdore he has another chance. ,\I hen they ;lre harpooned in shallow waters, such as in the Okhotsk Sea, the whales of this species dive almost at a right ;lIlgle to the surface and frequently hit the hottom.

P:\IUSITES: The external parasites of this species include ship barnacles, whale lice, pcnella, acorn barnaclcs, protozoans, ~tnJ bacteria, the last two of which leavc white scar marks. Internal par<biks inc1udc nematodes and Onchocerca, which infest the throat or liver. Occasionally, cysts of parasites arc fOllnd in the hlllhlH'r or in thc inguinal portion of the internal waH of the ahdomillal cavity.

lkrarclills anJO/o:i

Rcradills llmo/lXi, known as the southern heaked whale, was classified hy DUH!rIlOY in 1.3.=j 1. Somc of its characteristics are as follows: Vib.

1. Inhahits only the sOllth(~rn hemisphere . . J Condylohasalll'llgth ahont one-seventh of body length. 3. Total spread of tail f1u"es and length of flippers relative to total

hody length arc greate'r than in Remrdills bairdi.

\IOIII'IICH.OCY: .\Ithollgh Berardifls (lrmmxi is morphologically similar to B. "(lirt/i. the' Ilorthern sp('cies, tlH'rc arc some imporLlIlt diff('H'llc('s. The sOllthern whale' is slllaller, has proportionally wider tail flllkes and larg<'r flippers. and has a larger head relative to total hody It'ngth (onc-se'\"('nth of total in sOllthern whales, one-cighth of total in lIorthern whale'S). In addition, th<' sOlltht'rn ,vhale is slightly different ill color. It has dark hlllc dorsal skill, \ariolls hIlle-gray mottled pattl'm'i Oil the side of tht' hody, alld gray or light gray on the ahdomen.

.Ham11l111s of the Sea

DISTIUBUTIO:\,: This species is distributed only in the southern hemisphere and occurs primarily near :\ustT~\lia, New Zealand, the Falkland Islands, and South Shetland Island.

BEHAVIOR: Little is known ahout the behavior of the southern beaked whaJes except that they do not form large herds.

flyperoodon

The genus HyperoodoH was n~ulled by Lacepede in 1804. The follO\ving are the general characteristics of its memhers: 14b.

l. Adult body length less than 10 nL 2. Second pair of teeth situ~lted just behind the first pair. 3. Special protuberance 011 the upper surface of maxillae. 4. All cervical vertebral' fU~l'd.

Ilypcroodon (I111/Hill"!,,,;

Figmc 1-1(). J1YJlcflloci(l/I {/1I//lIIff(/t l j" kIlO\\1l as the hottl('(I()s('(1 whale. 11;11111:d by For­

ster in 1770.

16a. Onc characteristic of lI~II)I ' nl( tlml a11lpullallis is that it only iJlhahits

thc northern hcmisphere.

\IOIIl'1I0LOCY: This specie's is lll ndnate ill size .. \ 6.6 m specilllen \\"ei~hed 2200 kg. Adlllt mah,s an' 9.1 111. ft'lllales 7 .. 1 Ill. In hoth, the rostrulll ('x­tends forward in characteri,.,til' L1Shioll resembling the "bottlenose'· that prompted hoth the EIl~lisli alld the Japancse common names. The fore­head, which is rotllld alld hi~h Iwhilld tIl<' rostnHn, is particularly re­markahle ill l11al(·s, ill('reasill~ ill ,iZt' as til ' animal ~rO\vs. This large fore­head is prohahly ((sed ill n~htill~ for the f('males. The size of thl' forclwad is apparelltly r('lated Illaillly t() the <kv('lopmcnt of the maxillary bOIl<'.

In some illdividuals, tlU' top of tilt' for('head is (lattelled. The relativ('ly slllall eyes are ,itllated hehind anu ahoH~ thc corner of

the mouth. The hlowhol(, opells ~It the hase of the heightened forehead ahove the positioll of the eye. Tht' small dorsal fin is locateu well behind the midpoint of the hody. it is l:1Ir\'('d hackwards and the posterior edge is sickle shaped. The rlippers, too, an' rC'lativcly small.

General Biology 49

The dorsal surface is charcoal gray, while the venltral surface is very light gray. Both flippers and tail flukes are darker on both surfaces than the body. There is a pair of teeth at the anterior end of the lower jaw which may remain hidden inside the tooth ridge in many individuals even after they attain sexual maturity. The teeth are 4 to 5 cm in length and smaller than those of Cuvier's and Baird's beaked whales. In cross section, they are oval with a minimum diameter of 1.5 to 2.0 cm and a maximum diameter of 2.0 to 2.5 cm. In older whales, particularly males. these teeth gradually begin to fall out. Occasionally, vestigial teeth the size of toothpicks are found within the gums on either the upper or lower jaw. The vertebral formula is C7 + T9 + L9-11 + Ca18-20 = -t3-----t6. The flipper has five fing(>rs of I: 1, II: 5, III: 5, IV: 4, and V: 2.

DISTHlUl·TIO:-..": In the Arctic Ocean, where the majority of hottlenosed whales occur, they are found both in the European and Asian sides but are not frequently seen off central Russia. Populations extend to \vaters off ~ewfollll(l1and and Holland in the Atlantic Ocean. [n the Pacific, they are fOllnd in the Bering Sea, Okhotsk Sea, and probably, but withollt certain cOllfirmation, in thc Japan Sea. They do not appear to be ahundant in the eastern Pacific.

\hCll\TIO:-.." .\:>0;0 :\I\C:-'J>.\:>O;CE: Sillce many of these whales are found on the beaches of England, Holland, and France during autumn and winter, trwy may he migrating sOllthward at this time of the year. In SlIIllI1Wr, they an' assllmed to remain in the :\orth Sea and ;\rdic Ocean.

Fooo: ;\lthollgh hottlcllosed whales, likl' the other memhers of this family. consllme a wide variety of food, they se('1ll to prefer s({uid.

HEI'HOf)U:TIO:-..": Very little is known ahout [('production in the hoUlcl1osed whale, hut caIn's are ahout :3 m in Jell~tJl at the time of hirth.

13J.:II.\\"IOIl: This species gClleraly forms small herds of lip to ten whales. Croup strandings haH~ h('('n rq>ortcd.

\\"II.\U:>O;C: In the late nineteenth cenhlry, after the diminishing of the Greenland right whales and hefore the heginning of the fin whale ex· ploitation. this species was hunted extensin·ly in the Arctic Ocean. [n addition to the \ .... hale oil which was produced from the hluhber, spermaceti was taken from thc 1)\\lgillg for('lwad.

50 Mammals of the Sea

Hyperoodon planifrons

----~

----------..r===- ~ __

. - --~ ... ' ~: .--

Figure I-Ii. fIljpcroodon planifrons, known as the solilhem boufenosed whale, named bv Flower in I8H2.

16h. Hyperoodon planifrons inhabits only the southern hemisphere.

~(OHPflOL(X:\": This species is very similar in appearance to IIyperoodoT1 ampullaills. The hody is pntssian blue on the dorsal surface ami slightly brownish-grar on the ventral surface. The forehead is high('r than the base of the rostnlIll. In fact, the most markcd differences hl'tween this specil's and IIypcroodon al1lpullallls are that the forehead of the males projects to a greater extent in this species anu th(' dorsal fin is larger in proportion to houy length. The flukes are relatively large. and hody length relative to f1llke width is ahout 3 .. ~ : 1. ~(ales rcach 9 m in length and females reach 7 m.

The \"crkhral forml1la is C7 + T9 + L 10 -7- Ca:20 = "16. [n a spf'cimen ahol1t 7 III long. the skl1l1 was ahout 1.-1 m. The crest of the maxillary is quite high. Til . cartilag' ill the rniddc of the H)JJwr ends at the hase of the center nf the nose and is not ossified. :\1\ til<' sev('1l c('Tdcal \"('rtehra(' arc fllsed. ,lIIel, til<' first s('\"(~ n of the nine pairs of ri.hs art' hicuspid. :\1-though the -.tCrIllIlll is fOIlT-jointed, the third anel fOllTth pieces arc often ftlSf'd. The flipper has five fing<'fs of l: :2. 1[: 6, III: .~, IV: -1-:), and V: :1. There are clllllnlonly tt'll ch('\Tol\s. Thl' pl'h-ic bOlwio.; quitt' slIIall in relatioll tn th(' hody I<'n~th (ahout 10 CIII l(ln~) ;11](1 is positioned jllst IInder the last 1111111>ar \l'rkl'JT;l.

DISTIll ilL TIO:\": It is assullled that the whales inhahit tlH' ocean ('TH:ircling Antarotica, hilt they are seldom OhSt'T\Td in the whaling ground along 60 S. ;\ III II II ()('r of 1)(';IclH'd specimens ha\(~ 1)('('11 coJlecit'd from til<' heachcs of .\lIstralia and ~l'w Zealand.

General Biology 51

Ziphius

The genus =iphius was named by C. Cuvier in 1523. Some of its char­acteristics are the following: 17a.

I. One pair of large conical teeth in the tip of the lower jaw. 18a.

2. Only one pair of teeth in the tooth row; the other teeth always rudimentary.

Ziphius cadro5tris ---' --

- -_. __ .--- - '

Figure 1-18. Zi/JiJills cat·i((J.\tris, known as euvier's beaked \\ holle, named by C. Curvicr in 1823.

OnIEn CO~(~IOX ~.\~IE: Coose-beaked whale.

~loRPHOLOGY: The males reach a length of about 6. -1 m, and the females are slightly shorter. The color of goose-heaked wh.lles varies from brown or gray to black and is very often pale in the bee region. One young specimen caught near New Zealand was purplish tLtrk hllle on the back, brown on the side, white on the abdomen, and I rown on the fluke. The mother whale, which was also caught on the same occasion, was ultra­marine on the hack and white on the ahdomen. The adlllt animal hore an abundance of oval white spots, particularly in the calldal region. These white spots (scars) arc assllmed to he the marks left hy parasitic hacteria or protozoa.

The distance betwecn the snollt and the blowholt' is short, reaching onc­eighth to one-tenth of the body length. The entire skull is relatively wide. At the anterior joint of the orbital fossa, the width in proportion to the body length is br<'l'st among whales of this family. Occasionally, fifteen to forty vestigial teeth the size of toothpicks are found in the upper and

52 Mammals of the Sea

lower jaws. The normal male tooth is about 7 em in length and 4 cm in maximum diameter on its O\·al cross section. Females generallv have teeth hidden inside the gum.

\Vhen viewed laterally, the lower jaw looks thicker than the upper jaw and the rostrum is short and broad. The trunk is relath·ely long. but the caudal portion behind the anus is short. The dors;}l fin is triangular and <.:llfves backward with a convex posterior edge. The tail fluke has two very small notches at the center of its posterior edge. The vertebral for­mula is C7 + T9 + Lll + Ca20 = 47. The flippers are relatiH~ly small ;}nd have fh·e fingers, the bones of which are I: 1, II: 3-6, III: 5-6, IV: 4, <lOd V: 1-2.

DISTlU8CTIO~: Ziphills cacirostris is distributed in most of the oceans of the world. Though neither the northern nor southern limits have been determined, it is assumed that these whales do Dot migrate into the Bering Sea, the Arctic Ocean, or the Antarctic Ocean.

~hCllATIO~ .\:-';0 ABU:-';D:\:\,CE: Near Japan, Ziphills carirostr;s migrates north­ward along the Izu Island chain toward the top of the Boso Peninsula and passes off Cape Choshi. They are known to go further north , passing to the southeast of Hakkaido, hut their migration routes thereafter arc not yet known.

Individuals of this spe<.:ies hegin to appear regubrly in Japanese \vaters in January and February. The fre(lllency of sightings increases in \fay or June and reaches a peak in July to Septemher. Thereafter. the abun­dance decreases, though some animals arc seen thfoughout the year in one area or another.

Foo£): These whales feed on a wide variety of or~aI1isms, and thol\~h they prefer sqllid, they may also cat demersal fishes, ~t.'a cllclImher, crahs, and even star fish.

HEPI\()\)l·CTIO:-.i: The capture of a swimming jlIH'nile .'3.1 m in ,lcngth sug­gests that cah-('s afe prohahly h'ss than .1.1 III at hirth . Indi\·idlIa]s arc tholIght to attain sC.\lIal matlIfity at a Icngth of ·L5 to .3.0 m. AdlI lt males reach a maximllm length of arolInd 6.T fll. Females :1Tl' an an'rage of :10 cm larger. ~('ar Japan. mat\If(' adult spc'cinll'lIs of .i-t to (L.) III arc most ahllll­dant.

Ih:II .\\·IOIl: Very little is known ahollt the heha\ior of this whale. The hlows arc neither vcry large nor conspicuolIs. \\"hell they arc cllasc'd hy catcher hoats, they arc seen to dive for as ]on~ ;\s thirty lllinlItcs. \Vlwn starting a d('<,p din" they show the flllkcs high in the air and dive a 'llllost at a right angle to the sllfface. Herds scem to he small, even dllfillg Bli~rati()n.

)

General Riology

PARASITES: ~Iost of the wh~Lc's of this family are infested \\ith Onchocerca,

a parasite which forms a tr.U1sparcl1t cyst in the liver and br; nx. ~('ma­todes are frequently found in the stomach. Cysts, very simibr to the ones found on the skin of sperm \\-hates, are occasionally found in the skin, and nematodes are frequently found in the stomachs.

~hSCELLA.l'lEOUS: This species is found beached more frequently than any other species of Ziphiidae. _\t least two to three beachings ~lre reported annually on the Pacific Coa.sts of Japan, usually in Sagami &ly. Specimt>ns have also been found ashore in Sweden, England, France, Spain, Corsica Island, east coast of the enited States, west coast of the United States, South America, Cape of Good Hope in South Africa, India, Queensland (Australia), Tasmania, and :\ew Zealand. It is not known whether beached whales are whales beaten during fights, old whales, or even sick whales.

TasnUlcetu8

I8h. The genus Tas11l(lcetlls \\-.15 namcd hy Oliver in 1937. Its principal char­

acteristic is that its member - ha\(~ OI1C pair of large teeth in the tip of the lower tooth row and somc functional tceth in tooth rows.

Tasmacetlls shepherdi

- - ------ - ---- . -.

Figme 1-19. '1"(/.\/11(/0 '1 us ,III J I. reli, L:n()wn as the Ta\I1l;l1l heaked \\ h.dl', nailli'd hv Olivcr in 1937.

MOHPHOL()(;Y: BccallS<' of the v(,ry small nllmhers of specimcIls that have been examined, a delaikd dl',criptioll cannot he made. C('ncrally, however, the body of these \vhall's is .dJOut (j m. The dorsal body surfacc is hlack, the ventral surface is whit(· , amI tIl<' side is conTed with grayish-yellow strip(·s. The head is quite rolllld .lIld has a thick, short rostmm. The 'yes are relatively large. The upper i ~ l\\'S contains nineteen functional teeth on 'ach

54 J[ammals of the Sea

side, and the lower jaw has twenty-six rebtively 1arge teeth, as well as one pair of very large teeth at the front.

Members of the Family Ziphiidae usually have a small number of uni­formly shaped teeth. The fact th'lt this species has a dental formula of -H­and a very well developed tooth struchlre may eventually result in its reclassification. For the time being, howe\-er, it is included as a new genus in this family, following Fraser (1948).

DISTRIBtrrION: To date, the only three specimens reported were all from the Tasmanian Sea, near New Zea1and. Their distribution in other areas is not known.

Mesoplodon 17b.

The genus Mesoplodon was named by Gervais in 18.30. Its members can be distinguished by the fact that they h;1\-e one pair of 1arge Bat teeth in the middle of the lower jaw. This genus consists of twelve species. How­ever, the characteristics of some of them have not been clearly defined. More study is necessary.

Mesoplodon minlS

- ----~~--------~~~---

Figure 1-20 . . \lcsopio<ivTI mirlls, known as Trllc's l)('akccl whalc, namcd bv Tnsc in 1913. .

MORPHOLOGY: Although they resemble euvier's heaked whales, Tme's heaked whales han' a longer rostrllIll, a smaller head (one-fifth of total body l'ngth), and a pair of teeth at the end of the slender lower jaw.

General Biology 55

The dorsal surface is black, fading to slate gray on the side, and the abdominal skin is gray. There are frequently small yellow, purple, or pink spots on the body and occasionally a dark line in the center of the abdomen. In addition, there is a dark gray area on the ventral thorax. Some individ­uals have a pattern of brushed white around the navel and/ or genitals. The flippers are quite dark and are attached low on the sides of the body, which reaches a maximum length of 4.B to 5.2 m. The dorsal fin is located three-fourth of the distance posterior, and the tail fluke is \vide with a small notch at the posterior edge.

The vertebral fonnula is C7 + TI0 + LIl + CalB == 46. The phalangeal formula is I: 2, II: 4, III: 4, IV: 3, and V: 2. The first three cervical verte­brae are fused. The first seven pairs of ribs are two headed, and the first five of these are joined to the sternum by cartilage. The sternum consists of four sections.

DISTRIBlTIO~: True's beaked whales, like the other species of genus Mesoplodon, have very seldom been caught. Their presence is confirmed only in the North Atlantic. To date, none have been captured or even recorded in the North Pacific or in the southern hemisphere.

;\/esoplodon pacificrlS

Jfesoplodon pacificus known as Longman's beaked whale, was named by Longman in 1926. J/esop/odV1~ pacificflS was formerly considered a sub­species of .\lesoplodon mirus, but ~foore (1960) established it as a separate species. It is a relatively large whale, with a skull of over 1 m in It'ngth, and it has been found only in the South P;lcinc off southern Australia.

Mesop/odon hecton

,\lesoplodon hecton, known as Hector's beaked whale, was named by Gray in 1871.

MORPHOLOGY: In this species, only certain features of the skull can he descrihed. The premaxillary fossa is almost on the same plain as maxillary fossa, and there arc no grooves along the maxillary. The distance from the premaxillary fossa to the occiput equals the maximum width of the skull. The pair of teeth in the lower jaw of ,Hcsoplodon hectori is position cd \vithin a portion of a suture of the mandible, somewhat away from the position where the pair of teeth is fOllnd in ,\[csop/ocion mirus. Behind these teeth, there arc several sockets where \"estigial teeth arc prohahly located in the yOllng.

56 Mammals of the Sea

,\1 esoplodon gen:aisi

---

------------------Figure 1-21. _\ffsoplodvn gcrraisi, knO\\TI as the Gulf Stream beaked \\"hale. nallled by Deslongchamps ill 1866.

~IOHl)1l0LOG\': The head of this species is relath"ely small. The slope from the forehead to the rostrum is \"cry (rentle. The premaxillary fossae are located in front of the maxillary fossae and there are no side groO\"Cs on the maxillary. Here, ,is in .Hc.'Wploc/oa hectori, the teeth are present at the suture of the mandihle. The hody is higher than it is wide, and the dorsal fin is locatcd in the posterior quarter of the hody. The flippers [{'ach only about one-twelfth of the hody length. The flukes are also slllall and reach a total sprcad of about one-fifth of the hody length. The dorsal hody is grayish black, and the ahdominal area is somewhat lighter.

The v{'rtehral formllla is C7 + TlO : LlO --7- C .. 20 = "17. The first three cervical vertchrae arc fused and the flipper has fke fingcrs of I: 2, Il: 6, IlL 6, 1 V: -t, and V: :3, with some \"ariations.

DISTIHIIl.;T!O:\': The holotype of this species was collected adrift in the English ChanneL ~Iost of th' other specimens collected later came from the opposite side of the Atlantic: in Florida, ~cw York, LOllg Isbnd, tIl(' \Vest Indies, Cl\h~l, ~ew J('rs('y, and Jamaica. ~one have I>('('n fOlllld in tlw Pacific or Indian Ocealls.

General Biology 57

Mesoplodoll layardi

- - -----~ -----

Figure 1-:2:2 . . \lnollTution 1lJ'lllrdi, known as the strap.tootht:d beaked whale, named by Gray in 186.'5.

MORPHOLOCY: Indi\'iduals of this species rcach a m~n:imum kngth of .~.O to 5.8 m. The head is proportionally smalJi, and thc body, which is higher than it is wide. appears laterally compressed. The dorsal hody and the flippers are charco~lrgray and thc ventral hody is gray. The dorsal fin, located about two-thirds back on the hody, is rebtin'ly small and cun'es slightly backward.

The teeth. which ar' flat, tong, sharp, ana cOH'red with enamel, are located at the po.-.krior l'nd of the mandibular symphy~is. ~falcs have long, slender tecth which lllay migratc to the outside of thc maxillary as the body grows. The cOl11mon name of this whale deri\'cs from the fact that the teeth on the lower j~lw may grow to encirclc the upper jaw, gi\'ing the appearance that a string or strap is tied around thc llppt.~r jaw.

DISll\lBt:TIO~: Information Oil distrihlltion is limited. To date, all reports of findings. han: COl1le from the southern hemispherc (l\"('w Zealand, Australia, South .\fric\, and thc Falkland Islands .

Ueso,Jlodon !:!f(/!/i

Figure 1-2:3. .\1/ l'llloc/n/! gra'li, kllowll a.~ the ~ew Ze.d. 1111 <;calllp!.:J'dO\ .... 1l whale, named bv llaast in 1876.

58 .Uammals of tIle Sea

~IORPHOLOCY: The body shape is typical for Mesoplodon. The rostnml is is sharply pointed, and the girth gently increases from the head to the body trunk and then gradually decreases from the dorsal fin towards the tail. Like ~lesoplodon layardi, this species appears laterally compressed because it is higher than it is wide. The dorsal fin, which is positioned about one-third from the rear end, is high and triangular. Though the flippers are wider than in any other species of the genus, they are quite short (one-tenth to one eleventh of body length) and sharp at the end.

The dorsal body is olive drab, fading to brownish green on the abdomen, and except on the tail flukes and flippers, the ventral skin is quite pale. The V-shaped grooves on the throat are very distinct. The navel is located about the middle of the body. The blowhole is wide, opens anterior to the level of the eyes, and is positioned slightly to the left of the midline. The premaxillary fossa is positioned on or slightly behind the same cross section as the maxillary fossa. The side grooves of the maxillary are deep and very distinct.

The relatively small, triangular teeth are located at the posterior end of the mandibular symphysis. The teeth on the upper jaw are further posterior than those on the lower jaw. Ten or more vestigial teeth are often fOllnd at the base of the maxillary near the corners of the mouth. These lllay pro­trude from the gums, tho\lgh they arc usually buried inside the mucous membrane. The vertebral formula is C7 + TIO I Lll + Ca20 = -18. The first three cervical vertebrae arc fused. The first fi\"e of ten pairs of ribs are hicuspid and there are ten chevrons. The flippers have fh"e fingers of I: I, II: 5, III: 5, IV: -I, and V: 3.

DISTIHDUTIO~: Although this species has been found only in the southern hemisphere, most freqllently near New Zealand and .\lIstralia, it is also known to he distributed near Patagonia off South .\merica. In 187-1 an entire herd of twenty-ci~ht whales beached itself on the Chatum Islands of New Zealand.

Gelleral Biology 59

Mesoplodon bidens ------- -- .... ~ ., .. __ ----=-- _ = ..... ~~:=:=:::_=====~ .. -;;::.-====:.:::o?= =_::..::. __ :-_____ ._

Figure 1-:2-t .\Icsop[odon bidcrls, known .l.S Soweruy's heaked whale, named hy Sow­erby in ISO·!.

~rORPIIOLOGY: This was the first spet:ics of Mesoplodon known. The body is typically spindle-shaped, is much higher than it is wide, and reaches a length of .5 m. The high triangular dorsal fin is located slightly pos"tcrior to the middle of the hody and is clIr\'cd hack\vard at the tip. Thc f1ippcrs reach about one-eighth to one-ninth of the body length. Thc ends of thc tail flukes are pointed hackwards, and although there is no notch at the center of the posterior edge of the tail flukes, this area is rather concaved.

The entire hody is charcoal gray, somctimes with a slightly hlueish tint. Some individuals have a lighter-colored rostrum. \lost specimens hear nuny scratches, wOllnds, and \\ hitc 'CHS all over the hody.

\Vhen vicwcd laterally, thc rostrum appcars sharply pointcd. The pre­maxillary fossa is positioned towards the rostrnm from thc maxillary fossa. There arc no side grooves on the m'\\illary. Thc head comprises on Iy one­sixth to one-seventh of the total hody length. A pair of tceth is found on the lower jaw midway betwcen the tip and the anglc of gape. Thesc relatively large teeth facc upward while thc tooth roots facc forward. Freqllently, small vestigial teeth, which commonly do not grow Ollt of the tooth sockets, arc found. The \'crtebral form11la is C7 + TIO + L9 +­Ca.:20 = ·16. Thc fivc fingers of the lIipper arc I: 1, II: 6, HI: 6, IV: ·l, and V: 3.

DISTIUBUTIO:"l': This species is assumed to he distributed only in the Atlantic Ocean. Specimens havc heen reported from France, England, Holland, Belgillm, Germany, :\'o[\vay, Swedcll. Italy, and the cast coast of thc United States. To date, none have I)(:en found in thc Pacific or Indian Oceans.

I I 60 ).[ammals of tIle Sea

REPRODCcnON: Concrete evidence on reproduction in this species is limited. A 1.55 111 fehls was collected on December 13, 1392, and a 1.1 m fetus was collectl'd on Fehruary 3, 1926. On April 18, 1957. a 5.15 m female washed ashore on the west coast of ~orway, accompanied by a 3.15 m juvenile female (Jonsgard, 1957). The mother whale was not

secreting milk. Jonsg!lfd (1957) assumed the following: that the breeding season is in

February through April, that ge~tation is i1bout tweh'e months, that the young are about 2.0 m in length at birth, that lactation lasts ,1 year, and that the young may grow to 3.0 m by the end of lactation. .

BEH.:\.nOR: In the Book of \Vltale.'), Beddard (1900) referred to .1l1 individ­ual of this species which \\'as kept alive out of water for h\'o days after being collected in 1828. It ate bread and produced a low sound which resembled the mooing of a cow coming from inside a ca\'c.

J/esoplodoll ginkgoclells

.-----' --" -c-_ -' '- - • of - . --- .

- ... ..,

Fit'me 1-2.~ . . \I('S()}J/O<iOIl gi"k!:." d, ",, \"IlIlWIl ;\S the Japallese heaked wll.Ilc, 1I.lIned hv :\ishiwaki amI Kami\'a ill I (r5"i , . .

~[0IH'1I0LOGY: Thc hod)' of this sp(,l'i('~ is spilldlc-shaped alit! appears SOIllC­

what laterally cOlllpressed, TIl(, rostnllll is IOllg. alld it~ tip appears sharp. On the lower jaw IH'tw('('n tIl<' corner of the 1I1OIlth and the teeth, there is a projection of skin which pn'sS('s IIp\vanl against the Ilpper ja\\'. The dorsal fin is located toward tlJ(' H'ar of the h{)(ly. The flippers arc rather small, reachillg ollly OIJ('-lIinth to ollc-tcllth of the hody length. Thnc is almost no notch at the posterior ('d~(' of the tail flllkes.

s n

a t

1

General Biology 61

Although most of the body is midnight black, the abdominal skin is lighter in color, espl'cially where white scars remain from parasitic protozoa and baeteri,l.

The prem<:Lx.illary fossa is located considerably further anterior on the rostrum thm the maxillary fossa. There are no side grooves along the maxillary. The teeth are quite Hat and compressed. The width at the tooth crown is only about one-seventh of the depth. The location of a pair of the teeth found behind the mandibular symphysis varies somewhat according to sex. The \·ertebral fOnTIula is C7 + TlO -;- LIO + Ca21 = -:l8. Four of the seven cervical vertebrae are fused. The first scven of ten pairs of ribs are two-headed, allll there are eleven che\fons. The Hippers have five fingers, the hones of which are I: 1, II: 6, III: 5, IV: 4, and V: 3.

DISTRlBt:TlOX: Japanese beaked ,vhales are found in the southwest portion of the North Pacific.

"A-Iesop[odoH carlllllubsi

- - -, ~ • • 1, A'

-------Figure 1-20 . . \lno/I/Oc/(/II Cllrl/lflhh,·i. kllown ,IS 11111>1>'-; bl.'akcd whale, named bv Moore in I ( 0:3.

~IOHPII()LO('Y: Til ' pr('lllaxilbry fossa is Oil or slightly posterior to the cross section of tIl(' JIlaxillary fossa. The sidc gnlo\·CS along the maxillary are very shallow ami indistillct. The preprocess of the maxillary projects high just inside tIll' pr('orhital process at the h,ISt' of the rostmm, giving the appcarance of two pr('orhital proc('SSps Oll (,;\(.:11 side. Th· distance from the occipit.tl comlylcs to tllc~ hase of the wstnnn is It'ss than the lllaXilllllIll width of the sJ.dlll. The flat large teeth Oil the' 100\"('r jaw r<';tch 9 cm in length, 16 to l7 em or lIlore ill d<,pth, and 1.·1 cm in hreadth. The navel is ncar the \"('ntral lIlidl(,llgth of the hody. The flippers arc small, reaching onc-ninth of the IlIldy ICII!4tll. The dorsal fin is locat<'u on the samc cross section as the ;tUIIS, ahout orlC'-third forward from the posterior end. The vertebral forlllllla is C7 -r- TIL + 1.9 + C.d9 = ·16. Only the first two cervical \ l·rtehrae are fllsed. The first SC'\l'n Ollt of ele\'en pairs of ribs

·1 62 ~(ammal~ of the Sea

are two-headed and the last two pairs of ribs are very short. There are eight to nine che\"Tons. The sternum has five sections. The phalangeal formula is I: 1, II: 5, III: 5, IV: 4, and V: 3.

DISrRIBUTION: This species has been found only in the North Pacific.

~f esoplodon stejnegeri

Figure 1-27 . . \lCS()IJ/vcivll stcjrH!gcri, known 3S Stejneger's beaked whale.

OnIEn Co~nlOX ~.HI£: Saber-toothed whale.

~fORPIlOLOGY: These whales are all hlack and may grow as large as 6 m. The maximum height of the hody at the middle is greater than the width. The dorsal fin, which is triangular alld curvcd at the tip, is positioned three­fifths to two-thirds of the distance posterior to the tip of the snout. Thcre is J. distinct keel on the tail sock from the anus posterior to the center of the flnkes.

The holotype of this species is the skt'leton of a jllH'nile which washed ashore in the Aleutian Islands. ;\lthollgh the poor dcvelopment of the preorhital process of this specimen was originally attrihuted to its a,!!;C'. it was later confirnwd in sp('cilllcllS frolll the west coast of the UnitC'd States and from Japan that the pn·nrhital fossa is poorly dCH'lopcd ('\'ell

in adults. The preorhital notch is abo poorly dCH,lop<,d and is almost as far from the occipital condyles as the sklllI is wide at its greatest width. The premaxillary fossa is lo<:at<'d on or slightly posterior to the eross section of the maxillary fossa. The side groOH' along the maxillary is indistinct.

TIle width of the 10\\'cr jaw increases rather suddenly jllst posterior to the teeth. The teeth, located on the lowcr jaw, are qllite large (ahout 10 cm

General Biology 63

long, 16 to 17 cm deep, and 2.15 cm broad) and have a straight leading edge which faces forward and is frequently worn.

The vertebral formula is C7 + T10 + L10 + Ca19 == 46. The first to third cervical vertebrae are fused. The first seven out of ten pairs of ribs are bicuspid. There are nine to ten chevrons. The sternum is composed of five sections. The Hipper has five fingers and the phalangeal fommla IS

I: 1, II: 5, III: 4, IV: 4, and V: 3.

DISTRIBUTION: This species has been found only in the North Pacific.

Mesoplodon bowdoini

Mesoplodon bowdoin;, known as Bowdoin's beaked whale, was named by Andrews in 1908.

MORPHOLOGY: In form, this species is very similar to Mesoplodon stejnegeri. The first specimens \vere collected in New Zealand, but many specimens collected and initially identified as Mesoplodon bowdoini were later cor­rected to some other species.

DISTRIBUTIO:'ol: To date, this species has been found nowhere but in the South Pacific.

Mesoplodon densirostris ------

Figure 1-28 . . \lcsOp/Oc/OIi c/tll\iruslris, knowil as I3laillville's beaked whale, named by llIainville in 1817.

MOI1PIIOLOCY: The body reaches ·L=J m in length and is spindle shap d, the width being I('ss thall t II(' lH'i .~ht. Th(' hody height is greatest at the middle. The dorsal fin is I()c;lted ,illst I)('hind the middle of the body and is triangul'ar, high, sharp at the end, and curved hac~'ward. The flippers are

64 'la11lT!wls of the Sea

rather small, reaching about one-tenth to one-eleventh of the body length, and are narrow and sharp at the tips. The notch in the middle of the posterior end of the tail Hukes is negligible. The body is black \\-ith a very slightly lighter abdomen. The inside of the month is gray mixed with pink.

The premaxillary fossa is almost on or slightly posterior to the cross section of the maxillary fossa. The side grooves along the maxillary are very shallow and indistinct. The single pair of teeth is located on a large, wedge-shaped prominence hehind the S)l11physis of the mandible, and the tip of the tooth faces backward. This prominence, which starts just in front of the eyes, is particularly marked in males. Although the tooth is fairly large, about :20 em in depth, 9 cm in length, and 5 em in hreadth, only 1.0 to 1.5 cm is exposed. (The exposed portion looks like a hump on the prominence.) The rcmainder is buried in the gum.

The vertebral formula is C7 + Tll + L9 + Ca:20 = -!7. :\ceording to Raven (19-12), the first seven of eleven pairs of ribs are hvo-headed and the first five pairs arc jOined to the sternum by cartilage. Cervical ribs, different from the ordinary ribs which form the thorax, are occasionally attached on the last cervical vertebra. The sternum is made of five seg­ments, and thollgh the flipper has fh'e fingers, the phalangeal formula is not known.

DISTHlUCTlOX: .\Ithou~h [('ports have heen limited, this species appears lo be widely distributed. They ha\'e been reported from lhe Seychelles ill the Indian Ocean, South Africa, ~lassal'hllsetts, ~ew Jersey, and ~radeira. These reports indicatc that these whales arc distrihuted in tIl<' :\orth Atlantic .. South :\tlantic, and Indian Oceans but not in the Xorth Pacific. They further sug~est that Blainvillc's beaked whale is a warm "'akr spl'cies allli may not \"('Iltmc pole,vard heyondl.=5 } ill either hemisphere·.

F .\~IILY ~fO:,\{)D():-';TlD:\E

~fonodolltidac can he distin~lIished h) the following: I2h.

1. ;'\0 ~roo\l'S 011 throat. 2. \\'h<.'11 prescllt. dorsal fill at or ncar middlc of hody. 1. Notch of tail fill kc's cOlISpicll0I1S.

I9a . . l. Sevcn ccn ica I \'('rtt-i>rae all scpara te.

20a. S. Bcak ah'icllt. G. 7.

Dorsal fin ahs("lIt Of rIldillH'lltarv. .I

Inhabit Arctic r('~ic}Jl.

Gelleral Biology 65

This family consists of two genera each h:n'ing a single species .. Uthough the proportional measurements of the skulls of these two species are similar, the remarkable differences in the teeth ha\'e prompted some taxonomists to set up separate subfamilies for each of them. However, they arc treated here as members of the same family"

Delphinapterus

The genus Delphinapterus was named by Lacepede in 180-1. Its members have the following characteristics: 21a.

1. Eight to ten teeth in upper jaw. 2. Tooth length less than 5 elll.

Delphi1laptcrus lellcas _ . r ~--_

Fit,rurc 1-2~) , DI'iJlhir}tllJt crIls lellell'-, k.lluwn as the la'IIlK', 1I .lmco hy P.dbs in 177(1.

OTII}::H CO~f~(():,\ :\ ,\,,1-:: \\"hite whale.

\[OHl'IIOLOCY: The head is roulld and hlunt and the 1l101ith .is large. Instead of a dorsal fin, ther is a hllmp ahout :J to .3 em hi~h alld to (' 111 l(lng Ilcar the middle of the h.lck. TIl(' flippers arc rouIld, wide amI fall-shaped.

Adults are Ii~ht in)ry and seldom have scars or 'ipots. I [mH'Yer, th young (until ag 's ,I or .=5) arc marine hlue gray, and ynlln~('r ill(lh'idllals have dark, fill "pots on the skin. These spots gradllally I)('collle ~rayish­yellow as tlH' whal(' maturcs, finally hlending into whit '. Jndi,'idllals lllay reach a kngth of ;J,.) J1l, hllt tlJ(' 1l:o.IlalmaxillJllm ICIl',th is frolll :17 to ,l.:J m.

The pre llla\ilbry is flat and the portion ill frollt of the Ilostril is slightly cone;\\'cd. The skllll is asymmetrical and the hl n\\'hol(~ lies toward the left. The vcrtehral formllla is C7 + Tll-12 I- LG-<) -, Ca2.1-26 _ .!)O-.=51. The flippe r has fiv e fill~('rs of l: 1-2,1[: H-7, llI: ,l---3, L\": 2-1. and V: 2-1.

DISTHIII CT1():,\: Iklll~as arc fOlllld primarily in the .\rctic Occan hilt migrate as far south as .')0 :\. Sergeant and Brodie (Fl69 a.b ) han' recently

Mamll/als of tIle Sea

sumJllarized thr migration and distribution of this species in northern

Canadiall waters.

~fJ(;I\ATlO:-," A:-."O AIIC'IlA:-."CE: Canaua conuucts rolltillC' 1)('licopl<'r surveys arolllld ] luuson Bay in oruer to dell'nnine the ahlllldanee of 1)('luj:!as and regulate thc·ir catd .. The white illdiddllals are easy to spot against the backgrounu of hIL1C' wal<'r as thcy migrate alollg the cast eoa~t of North Amc-rica from tIle Ar<:tk·. The)' occur in ahllndallcc' in tllc' Da,·is Strait, Hl\dson Bar, alld tIle Gulf of SI. Luwrcllcc, amI individllals frequently migrate up' tl.e 51. Lawrence to Quebec. This specic's is also fn ·quently oLsen·ed along the Alaskan coasts, hut an ac1ccjlJatc· sllfn'y of tklt popula­tion has Jlot yet b(,(,11 made. Sightings of illdidduals han' heen recorded at Nulato, ahout llZO km lip tl.e Yukou River. Jklugas are abo ahundant alollg the northern coasts of 1'\orwa)' and Swpdell. ]n cold wintc'r~, th(,y migrate southward along these eoast lines, sonwtilll('s going as far south as the Haltie S('a. In the U.S.S.R. belugas )!av(' hC'(,1l caught hy heacl. seine. CUTr('nt ('stima(('s of the entire world population range' from 5,000 to 10,000 whales.

FooD: \\'hite whales f(,ed primarily on fairly large' henthic fishes such as halihut and f10llnder hilt may also eat squid and crahs.

REI'1I0DLTCTIO:-.": Belugas hreC'd ill April and ~fay and gin' hirth ill JUlie and July, after fourteen months of pregnancy. At birth, the calf is ahout 1.5 min length and dark in color.

BEII .... VIOH: ~orrnally, these whales fonn small family herds of fi\"(' to ten indi,·iduak During thC' southward migration, howl·\·el", many families join to form a largc· herd of one hUlldred to two hundrC'd whales. Belugas dive very well. \\'hen thC')· arc surfacing to brC'athe, their \·ocalizations can be heard even Lefore tl}('y rcach the surface.

Lo!'\GE\"IH: This species is assllmed to live thirty to fifty years, but studies on age determination arc not yet adequate.

M0710do71

The genus MOllodoJl was named by Linnaeus in 1758. Its members have the following general characteristics: 21b.

1. One pair of teeth in upper jaw. 2. In the adlllt male, a tooth (usually only left side) is elongated more

than 100 em ahead of rostmm.

CClIcral Biology 67

"I01lOd(J1/ mOH{)Ceros

--- ---- ; .. · ,....N -- -

Figure 1-30. ~/(ll/od(ln 1IWllOcnos, \';IIU\\,II as the narwbal, naJlled by Lillll;t(·U\ ill )75 .

OTJlEH CO~BW:\ ~,>\~fES : :\tollodoll, unicorn whale.

:\!cml'lIou)(:\,: The maxillltllll hody lellgth is ahout 4.0 to -tS In, excluding the kllgth of the tooth . Th" larger measurements of early whalillg days may han' included. the tooth. The head of this spccies is round. hut rela­tin'1y small. :\ ~{'ries of bumps allout S em high on th(' ]atter half of t11t' hack replac('s the dorsal fin. The flipI)('rs arc small, round, and hlunt 011

the cncl. ) n females, the t('etll JH'\"('r ('wpt from th(' gUIll . After males attaill

s('xua1 maturity, tll(' tooth Oil their ldt upper jaw gradual1y grows forward in a cOllllterdocl-"wise spiral, often attaining a length of 2.5 In (two-thirds of the body length). On rare occasions, tecth d('vclop on both sicks.

The color of the skin \ 'aries with ag('. Young animals arc dark blue gray, gradual1y changing to hrownish gray as they mature. At the same tjme many dark blue gray or sted gray spots become clear on the dorsal skin from the head. to the tan flukes. There are seldom spots on the abdominal skin.

The maxillary and premaxi1lary are well de\'eloped. The root of the tooth extends into the skull 20 to 30 cm. The ratio of the condylobasal kngth to the maximum width of the shIll is 2 to 1. The vertebral formula is C7 + TIl-12 + L6-10 + Ca26-27 = 50-55. The flipper has five fingers \\ -i th a phalangeal f onnula of 1: 1-2, II: 5-8, III : ~, IV: 2-4, and V: 2.-3.

DISTIUBtiTIOK AXD AnuxDAKcE: Nan"hals are found in the Arctic Ocean oc-curing in greater abundance near Russia than off American coasts. In spring, they migrate as far north as the packed ice fields. This species was once hunted with hand harpoons or spears for its strong teeth and for oil LIken from its thiek bluhher (blubber thicl,,"llcSS ranges from S to 10 cm " 'itll an a\'eragc of 7 to 8 ('Ill). \Yhen it is harpooned, the Nan\'hal dh'es

6S ~[ammals of tTle Sea

diagonally into the sea as deep as 300 m but usually rehuns to the surface after onk a few minutes and is easily caught. Since the population has declined' and the demand for those materials has <lecreased, the hunting operations are much less active. The present population is estimated to

be 1,000 to 3,000 animals.

FOOD: Nan, hals feed mainly on squid but may also eat cod, rockfishes, flounders, shrimps, and crabs.

BEHAVIOR: Narwhals form small groups, generally consisting of ten or fewer individuals, which usually include males, females, and juveniles.

There are many theories on the function of the extraordinary long tooth. For example, one writer hypothesized that the tooth was developed for breaking breathing holes in packed ice. Another assumed that the tooth was used to dig the sea bottom in search of food. Still others speculated that the tooth is used like a whip to shepherd the school. To me, the most acceptable hypothesis is that the long tooth is a weapon employed by m~lles in fights to win the females.

F.\~IILY PL.\TA:":lSTID.·\E

Platanistidac have the follo\\ ill~ charact('ristics: 20b.

1. neak extremely lon~ (ollc-sixth to one-seventh of hody length L . ., Low dorsal fin present, base length long. :3. Illhahit fresh water in tropical or warmer regions.

The dolphins of this family inhahit only largl' freshwater rivers. Since they arc believed to he l1IorpllOlll~ically similar to the ancestors of ceta­ceans, the study of skeletolls of this family may provide important insight into the history of whales .. \lthnll~h the' skuf1s of Platallistida(~ aw n'ry similar to those of Delphinidae. the \Tntricles arc not nearly so compressed or well evolvcd. The cervical n 'rtchrac arc rather large, and there arc gellerally ei(rht pairs of lwo-hl';I<Icd rihs. The roStrtllll is \"('ry lOll),.! al1d

slender.

Platani8ta

The (Tenl1S P[(Jillllista was ll;tllH'd hv Lessoll III rS2H. [t.<; IlH'1l1h('rs haH~ the following general charactt'ri~til's: 22a.

L Inhabit the Ganges. 2. Twentv-seven to thirt\· teeth \ll each row.

~ .;

j4 General Biology 69

Platanista gangctica

Figure 1-31. Platallista gangetica, knO\vn as the SlISU, named by Lebeck in 1001.

OTHER CO~[~[Q~ N:\:\IES: Ganges River dolphin, gangetic dolphin, blind dolphin.

:\IOIU'IlOLOGY: Adults reach a length of 2.3 m with a rostrtll11 of about 30 em in length. The blowhole opens in parallel to the hooy axis. The body is light tan to black. The eyes are extremely small and are believed to ha\"e no sight. The dorsal fin is locateo slightly posterior to the middle of the hody. A keel runs from the dorsal fin to the center of the fluke. Another keel nms along the abdominal side from slightly posterior to the anus. The hroao, large flippers are almost rectangular in shape. The f1l1ke is wide and its posterior edgc cllrves hm"ard the center, where tlH're is a notch.

The vcrtebral formllla is C7 + TIO-ll + L7-8 + Ca:2l-:2.~ = o l~}-'~l. The fillger bones are 1: 2, II: -h5, III: "1-.=5, IV: oh=5, and V: .l-(J. Fi\OC of the ten pairs of ribs are two headed. The cenoical \Oertehrae arc rclati\Ocly large and long; thus, a definite neck portion is recognizable from the external appearance.

DISn{lIIt"TJo~: This species is limited to the Ganges, Brahmaplltra :11\(1 Indlls Hi\Oer systems.

Fexm: SIISU feed on dC'l1lersal fish or shrimps. They appear to he blilld and arc heli!?vcd to rake the IlIl1d with tht' rostrum, somewhat as dllcks do, to fllH.l food.

BEllo\VIOU: In order to hreathe, this dolphill Iwings tilt' tip of the rostmrn, followed hy ahollt t\\"o-thinls of the hody, out of tIl(' \vater and iInnH'­(liately di\O(,s agaillo This cntire process takes on)'y tlm'e S(,("OI)(I-; to COIn­plete and is [('pcaled at thirty- In s(,\"l'nty-second inteno:t1s" Occasionally, the ('ntirc body IC.';ln'''i the water during breathing.

Inia

The genlls If/ill was nalllcd hy lYOrhigny III U):1t. Its lIlt'mhers have the following gcneral characteristics:

70 Jlammais of the Sea

22b. 1. Inhabit the Amazon. 2. About thirty teeth in each row.

Inia geoffrensis

--- - - ------------- -

.....

Figure 1-3:2. Inia geotfrcTlsis, known as the Amazon dolphin. ll.unet! by BlaiJlville in 1817.

OTIIER CO~I~[Q:-.r NA~IES: Boutu, boto, bufeo, pink porpoise.

~fORPIIOLOCY: 'Vhen fully grown, this species rcacht~s a total length of 2 .. 5 to 3.0 m. Both the upper and lower portions of the rostrum are sparsely covered with long, slender, heavy hairs. The foreheJ.d is rounded. The apex of the dorsal fin is located ahout two-thirds posterior to th' snout. The ([ukes and flippers arc relatively large and wide. The eyes are \'ery smaU. The body is usually gray on the dorsal surface hcc()lllin~ paler on the sides.

DISTIUBt:TIO:-"-: This species is fOllnd in the upper :\mJ..lo ll Ri\'cr, as far 'L'i

2,500 km from the ocean. Individuals are most often reported from Iqllitos, PeT1l, and Leticia, Coillmhia, hut others are fOllnd ill the OrinO(:o' Hiver

• of V (,Ilezllcla.

BEII.\VIOn: :\cc()fdill~ to Bates, these dolphins lIsuall~' swim ill pairs. [t is abo reported that they have been observed copulating ncar the hanks of the river while floating ventral side up at the surface l)f the water.

In February of 106.5, the author ohserved a yOlln~ 1..5 III male of this species at StC'inhart .\(l'laril1Jn, San Francisco, California. The hody was extremely soft and formed folds when the head was mon!d from its llormal position. This dolphin sat with its flippers and tail Illlkes on the hottom of the tallk, moving its head in all directions as if it were watchillg the olltside with its vcry slllatl eyes.

General Biology 71

Pontoporia The genus Pontoporia was named by Gray in 1846. Some of the charac-

teristics of its members are as follows:

22c. 1. Inhabit the La Plata Rh ere 2. More than fifty teeth in each row.

Pontoporia blaindllei

'---

--. ---- ~

Figure 1-.13. POlltolJOria !Jlllim:iIId. kllown as the La Pbta river dolphin. Ilaml'd hy Gervais in 18·14.

OTIf}':n Co~nlO:'Il N.nIE: Franciscalla.

~f()nplI{)LO(;Y: This species is Illllch smaller than the Amazon dolphin, hardly r('aching 1.5 III C\'('n when flllly grm .... n. The length of the rostrllm relative to hody length is the greatest of any speci('s of dolphin. On each of the lower and IIpper jaws there arc fifty to sixty v('ry small sharp tceth. The head is rOllnd and the neck is prominent. The sevcn 1ar~e cervical vcrtehrae arc IInfllscd, thlls permitting the animal to make extensive move­ments with its head. There is a distinct dorsal fin ncar the middl· of the hack, the posterior portion of which continlles as a keel toward tIlt' tail f1l1k(,s. The flipp(,rs are large and trianglllar in shape. The first four pairs of rihs are two headed. The hody is hrownish or blueish but is gencrally palf" Some Iwarly white animals caught in the eastern part of thc La Plata Hin:r arc often called "\Vhih' Chost.··

DISTltllll'Tro:'l;: This species is fOllllel ollly in the La Plata HiH'r of SOllth Allwrica and in coastal waters illlllwcliately adja<.:ent to the ri\('r Illollth.

iJip()tc.'I

The genus Upotes was nam('d hy \fillc'r III 19l8. Some general charac­teristics are thc followin~: 22d.

l. Inhabit the Tllng Ting Lake . . J Thirty-three to thirty-six tn'th in ca<.:h rmv.

72 Mammals of tile Sea

Lipotes r:e.tillifer ---------- ------------------ --

Figure 1-3-t. Lipotes cL'xillifa, known ;lS the Chinese lake dolphin. lIanll:u by \ (iller in 1918.

OnlEH CO~{~lO~ N.U1ES: Chinese Ri\'(~r dolphin, white flag dolphin. pel c·hi.

\[OllPIiOLOGY: \Vhen fully grOWIl, this species reaches 2.2 m. Tht' d()rsal body is geIlerally slate blue or gray and the ventral surface is white, though both those eolors lllay he tUnleu brown in Illud. The narrow rostrum is about 30 em long and has a \cry distincti\"e Ilpturned tip. The hlowlll)lc is located. just aft of the forehead and slightly to the left side. The tri­all!.~l1lar dorsal fin is located slightly past the center of the hody. Th' ;llltl'rior edge of thc dorsal fin is slightly rounded or curled and the pos­terior ed!.!;c is slightly falcate. The total spr('ad of thc tail flllkes is ahollt one-follrth of the body Ic'ngth. Th' lIippers arc white. rollnd Oil tht' cdgt'. and tapered at the tip. Lik' the C ;lnges dolphin, the Chinese Lakc Dol­phin's ('yes are very small and thollght to he fllnctionless. The t' \h'm~t1 ear op('nings arc \"t'ry proJllinl'nt.

DISTllIlIl"TlO:'l:: This species is fOllnd nlainly in the Tung '[ing Lak· !lear tht' headwaters of the Yalwtze Hi\"C'r system of China.

FOOl>: This species f('eds prilllarily Oil fisJI('s hilt aJ'so ('ats other allilllals in the mlld. They relish freshwater shrimp that ha\"c a soft carapac·. \Iiller (19t8), who first scic'ntifically reported this sp('cies, rdrie\"('d a hm:kdflll of catfish from the stomach conh'lIts or the S('\"('ral specimt'lls he collected.

Rt-:l'ltO()CCTIO:'l:: Acc()rdill ,~ to tlH' Ilati\"{'s around the TlIng Ting I.ak<'. whell the water le\"(·1 of the lake increases in the spring, this sp('cies JlHl\ "CS

into the small, clear-water strl'alllS to hr('('d.

BEII.\\·HlH: In the winter, whcll the l<'n,1 of the lake drops, th('se dolphim are easily seen. They g('IH'rally traH,1 in groups of three or fOllr hilt ~()lIlC­tillles form grollps of l<'n or more illdividllals. The)' search th(' "hallow IIl\(ddy shore for hait fi ""hes ill lll1Jch thl' sallie way dllcks do.

General Biology

F.UIILY DELPH1~ID.U:

Delphinidae ha e the following general characteristics:

19b. 1. Two or more cervical vertebrae are fused.

23a. 2. Beak distinct. 3. ~fore than twenty teeth in each row of upper jaw. 4. Less than -l m in bod y length.

73

Delphinidae have a relatively large number of vertebrae, and only the first two cervical vertebrae are fused (in some old specimens, three or fOllr are conjugated). All have a snout; and there are more than twenty teeth on each side of each of the upper and lower jaws. The tail flukes have a notch at the center of the posterior edge. The rostrum is more than twice as wide as it is long. The cO'ldylobasal length is more than 1.7 times the width. There are ten genera in this family: Del/Jhill!ls, StclIl:lla, LagcnurhU1Il:!Hls, Cep!llI[orltUIU.:!IIIS, Tllrsiops, SUllsa, Sotaiia, Lcgenodel­phis, Lissuddpltis, alld StellO.

Lis.'iOclclp" is 24a.

The ('enus Lissudd/J!lis was lIaJllcd by Col~cr ill IH II. Its distill~lIishing characteristic is that it has no dorsal fin.

Lis.')()(ldpliis lwrc(Jlis

Fi ,~lIrc' l-:3.>, !.i,NJddl'his Imrnilis, kl1()wn as the :\()rtlH'rn ri~ht wllal.· dolphiJl, 11.llllt'd hy Pc.lk ill I ~ P,.

Some charact('rislics of U .\·wddphis lJ{}rc(Jlis are th(· following: 23a.

1. Slendl'r hody. 2. Ouler surface of flippns hlat:k. 3. Inhabits northern 1H'lIlisphere.

74 )(czmmals of the Sea

:MORPHOLOGY: Adults of this species reach a length of approximately 2.3 rn. The rostmm is extremely short and pointed at the tip. Tht' body reaches a maximum girth about hvo-fifth of the body length from the tip of the snout. The flippers are relatively smaU, very narrow, sharply pointed, ~md reach a length comparable to about one-eighth of the total body length. The tail flukes are also small, reaching a total spread of one-seventh of the body length. The notch at the center of their posterior margin is deep.

Except for a white patch on the belly and a very small white spot at the end of the lower jaw, the body is an black. The \'entral white patch is very narrow near the navel, widens again along the ;.lnus and the genital opening, and disappears on the keel of the tail stock.

The skull is very slender. The condylobasallength is :2.17 times the width of the skull. The rostrum is very slender but is only :2.18 times as long as it is wide. Although the end of the lower jaw is very n:.lfrow, the symphysis of the mandible is relatively short. The small teeth are all sharply pointed at the tip. Generally, the lower jaw has slightly more teeth than the upper jaw. The dental fonl1ula is ·t~:-g, The vertebral fonllula is C7 + T1-l-15 + L29-30 + Ca37-:39 = 88-90. The first two cervical vertehrae are fllsed. The first fi\'e of the fourteen or fifteen pairs of ribs are two-headed, and the sternum has four sections. The flipper has fin~ fingers, the hones of which are I: 1-2, H: 8, III: 9, IV: 3, and V: 2-.'3.

DlSTmIit;TIO~ ;\:-';D Aut;;>o;n .. \;>O;CE: This species is restricted to the North Pacific Ocean, where it inhahits relatively wann w~ltcrs. The population is estimatcd at morc than 10,000.

Foon: This species feeds mainly on squid and pebgic fish.

BEIL\\"IOII: Lissodd/,hi,') borcalis generally fonn herds of two hundrcd or more indi\'iuuals. A1though the groups move vcry slowly, individuals can swim \'cry fast, presllmably as milch as 3.5 km/hr.

V.\III.\TIO:-';S: Ogawa (1936) [('ported indi\'iduals callght off Kinkasan, Japan, whit:h were slightly different from ordinary specimells. :\lth()ll~h Ogawa considered the secolld grollp as L[ .... 'IOdelphis peroni, they will be treated in this work as L[ .... w)(/elphis borenli.') lllhircfltris, a sllbspecies of Li.'isodel/,his bar('(/lis. The dHr('f('IlCCS hetween the two slIhspecies arc sllm­marized as follows:

'I) 1 ( I. ". I :1 I. ('fila "rlllll a: i '2 . 1.\ ·

~ On \'('Illral slIrrac(·. whil,· r"lor d",·'1 not rOflt.inll(· (rom tip tI( I",\t'r j :lw 10 ,'.alk o( lail flllk.",. Dark ('olor on throat. ,,·hit., arl'n I ... rollll·s narro ...... arollnd 11,\\' ,-1.

:i . Innl'r slIr(:u'.· tlf flippl'r~ .. ntir.·ly black,

L 1·l\d.·rsllrfa ... ~ of bill.lnk.", dark.

Gt:'1lCral Biology 75

Figure 1-36. Comparison of L. b. borcali.!~ and L. b. albit;entris.

Li.uoJrl;ltu boreali" albicenlri$

I. Oelltal rormula: H:g.. t. White color on ventral ~urrace mo~ e1.ten:live and continuing rroUl tip or lower jsw ttl ,talk

or tail fluke!!.

:I. Only lower half of inner ~urfllce or t!ippers hl;u:k .

... l'nder'lllrrace (If tail Huh!! whit~.

Lissodc[phis peroui

- --Figurc 1-3i. Liss()(ldph~~ pcroni, ~Illlwn .IS thc sOllthern right whale dolphill. 1I.11l1l'd

by LinnaclIs in 1758.

Some distinguishing characteristics of Lissodelphis peroni are the follow­ing: :)!"")h _. .

1. Body stouter. 2. Outer surface of flippers white. 3. Inhahit southern hemisphcr('.

~1()Hl'I(OUX;Y: In the Antarctic Ocean, the \ .. ·hite ahdominal portioll of this species extends far lip the ide of the hody, leaving very little black skin. The lower and upper jaws arc hlack. The outer surface of the flippers

76 ).[ammals of the Sea

is white, and the outer surface of the tail flukes is black. Since there ha\"e been no specimens collected in the .\ntarctic Ocean, no detailed descrip­tion has been made.

DISTRIBUTIO:-';: This species occurs in the Antarctic Ocean.

BElLWIOR: Lillie (1915) reported that both Lissodclphis perolli and La{!,­eno.,lzy"cllUS obscurtls came close to his research boat, though the t\vo species ne\"er mixed.

Delphinus

The genus Delphillus was named bv LinnaeLls in 17.38. Some of its characteristics are the following: 24b.

1. Distinct dorsal fin present. 26a.

oJ An angle (or a groove) present behvecll heak and forehead, or fore­head makes a step from heak.

27a. 3. Dorsal fin triangular, has light color near middle. -t. Adults less than 2.15 m. ;). Rostrum length 11101"(' thall :2.S times its breadth. 6. Greatest skull hreadth I('ss than one-half condylohasal I<·ngth. 7. ~landilHllar symphysis less than onc-fifth of mandibular length. 8. ~laxilbry groO\"C presl'nt on pabtc.

Delphinus delphis

figmc l -:M~. Dd/Jhirlll"" cldphis, ~1I()wn as the cOlllmon dolphin, nalllcd !J\' Lirll\;Il'IIS in li.')S.

General Biology 77

MORPHOLOGY: ~(ales are 10 to 20 em larger th3ll females. and individuals reach a length of 2.1-1 Ill. The keel is not prano meed on either the dorsal or ventral side. The medium-sized dorsal fin is triangular in shape, sharply pOinted and curved slightly bach .... ard at the tip. The triangular flippers are also pointed at the tip. The total spread of the tail flukes is one-fifth to one-fourth of the body length.

The body color is distinctive and can he generally descrihed. though there are indiddual variations. The dorsal surface is black, the \'entral is white, and the sides are ochre and gray. Two arch-shaped boundaries on'rlap just beneath the dorsal fin and ma.rk a triangular region of dark color. Below the arc line from the portion a1:xn'e the Hipper toward the posterior end of the dorsal fin, the skin is gr.1y. :\.bove the line, the skin is midnight black. The portion of the body b ow the arc line drawn from just aDm'e and behind the anllS toward the po~terior edge of dorsal fin is gray. Two slate gray lines start from the eye, mn backward and eithl'r join or nm parallel to slate gray or yellow ochre sOllwtimes mustard yellow) portions which run from the anus forward. These lines are darker than

those in the cape dolphin. Another black stripe nms towards the lower jaw from the hase of flippl'r amI ev('ntually joins the black portion of the rostrum. In some specimells, this stripe extends forward ,dong the lower edge of the lower jaw amI then retllrns toward the p()stt>rior ed~(' of the Illollth formillg a \' shape which joins the (lark portioll on the upper edge of the lowcr j~IW . In other sp<'Cinll'ns, it ('xt('nll-; directly towards the pos­terior edge of the mOllth. Sen'ral hlack hands illside the gray portion ex­kil(l rWll1 thl' ('yes toward tlte hord('r of thL' rostrlllll, :\ gray. in)ry, or white triallgle cOll1ll1ollly appears ill the Illidl!!l' of the dorsal fin, I.igltkr stripe's rtlll from the hlowhole towards the horder of thl' fon'head and rostrllll1,

The color changes aft~'f <\<'ath. The trial\\! t' on th(' dorsal fin and the gray ochw\tripcs 01\ tl1<' side' ()f th(' hody f.ll!C or disapp('ar completely. Thc gray portion may turn to ochre, and the 10\\"('r surface of the' flipp('rs Ill:l\' also hdl' into a pal('r color.

TI1I'[(' are s('\"('ral hairs ()n each side of tilt' llpp('r jaw of thl' fetlls, hilt these hairs are lost lOll,!.!; hefon' thp allimal att.liIlS matllrity. Th • \' 'rt('hraJ formllla is \,7 + T ),1 + L21 + Ca11-:32 - ' ~ 7:),-7·1. Thp first two of th<~

S('\ '('n lTnical \Trt<-hrae arc flls(·d, FOllr to fI\(, of tIl(' fOllrt!'en pairs of rihs an' dOllhl(,·I\('adl'd. There an' fOllr "cdiolls in til(' st('rJllll1l. Thp phalallgeal forlllllla is L 2, Il: 9. [[T: fr-7. [\': J-I, and \': 1-2, Both the IIpper and lower jaws han' forty to fifty rc·!ati\ l'ly small (:3 mill diameter) poinkd teeth on <'ach row.

J)ISTHIIILTI()~ \~() All '~J),\~U:: As sllggested hy the English name, cOll1mon <lolphin, these animals occur fr<'qll<.'lltly in thl' ,\tlantic Oc<.'an and its ad-

78 JI(l11lmal~ of the Sea

jacent seas, where the population is estimated at more than 30,000 indi­viduals. They are also found in the Indian Ocean and in both the South and North Pacific but do not migrate into the cold waters. This species is not generally very abundant in Japanese waters. Small herds of one hundred to two hundred animals are found in the waters adjacent to Kyushu and Okinawa but rarely venhue into coastal waters. The widely quoted statement that "the common uolphin is most frequently observed in the Japanese waters" probably resulted from confusion of this with other species and from confusion in common names.

FOOD: This species feeds chiefly on schools of migrating fish such as herring and sardines but may also eat squid.

REPRODt:cnON: Both males and females attain sexual maturity at a length of 1.7 to 1.8 m, at which time they are assumed to be three to four years old.

LOXGEVITY: Individuals are assumed to live twenty-five to thirty years.

Delphinus capensis

Figure 1-39. Delphillus capcnsi ... , known .15 the elpe dolphin, named hy Gray in 18:28.

~IORPIIOLOCY: Although the hody shape and the color patterns resemhle those of the common dolphin, the rostnlm in this species is much longer and the houy colors are generally d~lTker. Instead of the two dark stripes whieh mn forward from the allus on the common dolphin, there is a sillgfe lighter stripe.

The length of the rostrum is about two-thirds of the condylohasal length and about :3.5 to 3.8 times the width of the rastmm. The dental formula of Delphinlls capcn.')is is ~~-:~~. The \"crtebral formula is C7 + Tl·t + L21 + Ca30 == 72. The first two cervical \"ertcbrac are fused. The first five of the fourteen pairs of ribs are douhle headed.

General Biology 79

DISTRIBUTION .-\~D A.Bu~A ... ~CE: Because many specimens have been cap­tured or reported near the Cape of Good Hope in South Africa, it is as­sumed that this species is distributed in the Atlantic and Indian Oceans and prefers wanner waters to an even greater degree than the common dolphin. The cape dolphin has been reported near Japan but is assumed to inhabit only the wann waters near Kyushu. The population seems much smaller than that of the common dolphin.

Delphinus bairdi

\ . , • I . "\

Figure I-tO. Dclpllinll.s bairdi, known .IS the Pacific dolphin, named by Dall in 187:3.

~fOHI'1I0L()GY: The body of this species is slightly heavier than that of the common dolphin amI rcaches a len~th of ahout 2.2 m. In addition, though tl1cy are generally <{uite similar, there are several si!4nificant differ­ences between the Pacific dolphin and the common dolphin. First, the dark stripes which rim from the eyes to the anus of the common dolphin are very light or ahsent and the yellow ochre stripes arc ahsent in this species. Th rostrum is slightly more slender than that of the common dolphin and reaches a len~th of morc than 1.7 times the maximum width of the skull. The flippers have a wider hase, and the stripe from the hasc of the flippers toward the lower j.tW is lighter.

DISTIU[)UTIO:'li: These animals arc found in the Xorth Pacific (from British Columbia, Canada, to Baja California, and ~fcxico) and often mih'Tatc ncar the coasts. They are not fOllnd in Japanese waters.

80 Mammals of the Sea

Stenella

The genus Stenella was named by Gray III 1866. Some of its charac­teristics are the following: 27b.

1. Dorsal fin leans backward, has no whitish color. 2. Adults less than 2.75 m long. 3. Rostnlm length of skull more than 2.2 times its breadth. 4. Greatest breadth of skull less than one-half of condylobasal length. 5. Mandibular symphysis less than one-fifth of mandibular length. 6. No maxillary groove on palate.

Stcllellll cllemleoalba -

", _ .. , . --~~~~~~======~~=~ ---

Figure l-ll. SfCll('llrI Cl:l'fldc(}rIlIw, 1-110\\1\ as the ollie-white dolphi1\, 1l;tIllCJ hv ~Ic\"cn in lR:33.

~fOIl1'1I0L()CY: The hody is the typical spindle shape of dolphins and reaches a maximllm len~th of :2.1 to :2.7 Ill. ~falcs are 11 . II ally 10 to :)0 cm larger than felllall ·s. TIl(' calldal portioll of the body behilld the anllS is much thicker than that of til cOlllmon dol'phin. The relatiollship of I('ngth to wei(fht ill this species can he r('presellted hy the formllla \V = o.OOOO()() X L l ".;.~, where \r is hody \veight in kiln~rams and L is hody length in centimeters. The triangular dorsal fin. located at the middle of tfle hody, is 1I0t as high as that of the common dolphin. The flippers arc triangular and clln·('<.\ inward sli~htly on their posterior ('d~('s. Th· total spreau of the tail Ill! kes is abollt one-fifth of the hody length.

The dorsal hody is dark prtlssian hlue, and the ahdomen. as far forward as the lllldersllrface of thc lowcr jaw, is white. The sides of hoth the upper and lower jaws are prm~ian hhH', and the tip of the ro~tnlln is particularly dark. Alollg thc boulldary, the dorsal hlllC and \'entral white are gradated. A hlack stripe runs from the rostrum and frontal to the eye on each side,

General Biolog.y 81

where it then divides into hvo stripes and continues from the eye to the anus. The eyes are comp{etely encircled with blue. The Hippers, dorsal fin, and tail flukes are black, but the undersurface of the flukes is somewhat lighter. A bbck stripe mns forward from the base of the flippers, finally joins the dark blue circle around the eye, and occasionally even extends as far as the angle of gape. That stripe does not mn to the lowl"'r jaw. There are no small spots on any part of the body.

The vertebral fonnub is C7 + TI5 + L:?2 T Ca:35 = 79. The first two cervical vertebrae are fused together. OccJ.Sionally, the third or fourth cervical vertebrae are found conjugated, but such fusions are the result of old age. The first five pairs of ribs, all of which are jOined to the sternum by sternal ribs. are two headed. The sternum h.l'i four sections. The skull is 2.3 times as lllng as it is wide. The rostrum comprises 36 percent of the skull length and is about 2.5 times as long as it is wide. The dental formula is .H:{-~. The heavily enameled teeth are rebtin?Iy small (about 1-1 to 15 mm long and :3 mm in diameter). The tips of the teeth are sharp and curved slightly illwanl

The fIippl'rs havc five fingers of I: 1, II: 9-10, III: 7, IV: -1, and V: 2.

DrSllHlH.iTIO:--;' .\:--;'1) AnC:'IiDA:--:cE: This species is found in the Atlantic and Pacific Oceans and the ~f('diterranean Sea but klS not heen reported from the Indian Ocean. Sincc the collection of the fi rst specimen in the estuary of the La Plata niver, South America, indh illuals have heen found in widely separated area~ of the Atlantic Ocean south of Greenland, llear Jamaica, in the ~1c<lit<'rrall('al1 S('a amI IIl '. lr Smith Africa) and ill the Pacific. The size of thc :\tlantic pOPlllation kl'i l10t hee'l1 elPterlllincd, hilt t 'IC' Pacific pi lP1l1a t ion appears to he hct\\"l'l'n 1.30,O(X) and 2(X),OOO all i lila l's. In fact. this lppcars to h 1 the most ahllTHLlIlt ~ pecie's ill Japanl'se waters, anel despite ,UlIltlat harvcsts of from 10,000 to :20.000 individllals, there is no indication that the population is cleclinin'..!. The'S(~ animals an' call(Tht olf tl\(., east C()~lS't of the IZII Peninsula tIurin g their sOlltihward migrations in Scptl'lIll)('r throllgh Ikcemhcr and off the \\"l"t coast of the sallle pClIill­sllb durin~ their return lIIigrations lIortll\\ard in ~fay through Jllly. Their mi(rrations north of the Samiku coast of I\:,l'..!()shima, Kyushll, have not \>('('n stlldied.

Fono: The primary food of this species is "qlli(l, particlllarly to/igo sp. ~rallY indi,idllah Jwar IlllIIH'roUS Illarks of \tl'lid Slicker discs aroulld the mOllth.

HEI'HOIH"CTIO:--:: Stlldics of spccimclIs callght at I\:awana, Fllto, and Inatori, on the ('ast coast of the IZI\ Pt'ninsllla, fC'\"(,;llcd hoth large and small fetuses Sillll1 itaneollsiy ill Octoher throllgh ))('C('lIIht'f. Sp('cimells from :\rari, on the west coast of the [zu Peninsula, simiLlfly prodllced hoth large and

82 :\fammals of the Sea

small fetuses from ~Iay through Jury. This evidence suggests that this species has two distinct breeding seasons, one in spring and one in fall, that each season lasts for a long period of time, and that parturition may occur in spring or auhlmn. Lactation lasts from six to twelve months, and individuals attain sexual maturity at an age of 4 years and a length of 1.8 to 1.85 m.

BEHAVIOR: These dolphins are gregarious, fonning large herds. Further­more, several herds may group together to fonn a group of thousands of individuals. The largest I have observed included about three thousand animals, all of which were juveniles. Herds more often consist of five hun­dred to one thousand or fewer, individuals.

These animals are very cowardly, and large herds can be chased into a bay for harvesting. Several to more than ten boats participate in the drive in which the dolphins are scared in the proper direction by slapping the water surface, by throwing stones, or by beating a tmmpet-shaped device designed to produce underwater noise.

LO="1CEVITY: This species is assumed to )j\'e twenty-five to 30 years.

Stenella styx

Fi~url' l-E~. Stcrwlla ,'tyr. krHl\\'ll .IS Cra:"s porp()i~t" Ilamed by Gray in 1840.

~lonpJ[OLOGY: Although these animals have frequently heen considered Stcnella cacru/roa/!Ja, tl1l're appears to I)(~ a distinct difference hetween the color pattC'rns around t}H' 'yes of the two species. Two dark stripes mn backward from the (·Y(l. olle to the axilla and another toward the anus. A branch of the second strip!' docs not reach the al1\ls. Another stripe runs from the anterior edge of the flipper to the corner of the mouth, fading in color after it passes 1Illdt'r the eye. The eye is in the dark portion hut is encircled with a white rillg which resembles a pair of glasses.

The rostrum is greater than two-thirds of the cOll<.lylohasal length. Both

lis dl, y

'1d .8

~r-

a \Ie

l e

ce

·d

s

Gi'Ili..'rai Biology S3

jaws have forty-four to fifty teeth on each side. There are seventy-six verte­brae and fifteen pairs of ribs.

DISTRIBUTIO~: These animals are distributed from south of Greenland to north of Jamaica (in the Atlantic Ocean). Since the holotype was collected on the west coast of Africa, they must also be distributed in the southern hemisphere. In the Pacific Ocean: they have been reported from the Bering Sea as far south as Oregon. None have been reported from Japanese waters.

Stenella malayana

Stenella malayana, known as the ~lalayan Porpoise, was named by Les­son in 1826.

~(ORPHOLOGY: Fraser reported that this species attained a maximum size of less than 1.8 m. However, Beddanl (1900) indicated that individuals may attain a length of 2.1 m. The body is all gray. There are thirty-nine teeth in both the upper and lower jaws.

DISTlUBUTIO:o.l: This species is oistributed near the Indonesian Islands and the ~(alay Peninsula.

Stenella longirostris

-- --Figmc I-n. Stnll"lla !ollgiro.ltr;s. ].. f\ ()wn as the long-hC'ak ' d p() rp() i't~. 11 .1 III I'd by Gray in 1871.

OTHER CO~(~lO~ l\';\~IE: LOIl~- :- llouted dolphin.

~IOIlPIlOLO(;Y: This specie's r('aclH's a m;t:ximllln l('ngth of ahout ~ . l m. The dorsal body is char<:oal-,rray. while the \'entral body is white or gray. Numerous fine gray spots arc scattered all over the body. The anterior half of the body is darker than the posterior half. The boundary where the dark dorsal and the light \'entral surfaces fade together into gray nms in an arch-like curve from behind the dorsal fin t(w..-ard the head. The black dorsal coloring narrows toward the front and reaches the horder between

MammalS ot the :Sea

the frontal head and rostrum. The upper jaw of the beak and the tip and lip of the lower jaw are also black. A black stripe runs on each side from the eye to the border of the beak and frontal head. Another black line runs from the beak bachvard beyond the angle of gape. From the eye, a small, indistinct dark stripe runs bad .... ward to the base of the flippers. All the fins (flippers, dorsal fin, and fluke) are dark. There is no dark stripe from the eye to the anus. The dorsal fin, which is triangular and leans back­wards, and the flippers are both small. There are forty-six: to sixty-five (most commonly fifty-five) teeth on each side of both jaws. There are seventy-two to seventy-three vertebrae.

DISTIUmrI10~: This species is abundant in the southern hemisphere. They are found near the Cape of Good Hope in the Indian Ocean and near Australia in the Pacific Ocean. In the northern hemisphere, some indi­viduals are caught in Japanese waters west of Kyushu.

Stenella lOllgirostris kllnitomoi

Stenella lOllgirostris kllnitoTlloi, kno\vn as Ogawa's long-snouted dolphin, was named by Kuroda in 1952.

~lonplloLOGY: This subspecies was described from a skull speci­men collected by Kunitomo in 1935 from a fishing boat operated south of the Goto Islands, ~agasaki Pref. The dental formula is ;, ;::~} and the rostnlll1 is quite long. The skull is about 2.8 times as long as it is wide. The rostrum comprises about 63 percent of the skull length and is 3.4 times longer than it is wide. Ogawa stated that this subspecies differs from the holotype by lacking fine spots.

Five dolphins of Stel1clla sp. wohich this author observed at Sea Life Park in Hawaii in January, 1964, lacked any dots on the body, though they othc['\vise closely resembled Stcllclla longirostris. Althollgh animals sllch as these, described by Ogawa, may constitute a new species, fmther study will he rCfl'lirC'd.

Stcnella Illicrops

StclIella lIIicrops was named hy Gray in 187l.

MORPIIOLO(;Y: This specics was descrihed from a small-headed porpoise collect~d at ~Ltria ~ra(1re Islanu ill the Tres ~farias Islands off ~kxico. The species hao; a l()n~ rostrllm which is narrow and sharp at the lip, broadest at the base of the prcorbital proccss, anu comprises over GO per­cent of the total skull length. The skull is rclatively small, reaching a maxi­mum width of less than 1.3 cm. There arc fifty .. one teeth on each side of the lower jaw.

The flippcrs are rather small. There is a little hump immediately behind

J

t I

General Biology 83

the anus in adult males. The skull and flippers of individuals of this species collected on the expeditions by the Erebus and the Terror of Great Britain

are preserved at the British ~{useum.

BEHAVIOR: Infonnation on behavior is limited. One distinctive behavior of Stenella microps, however, is that animals jump clear out of the water and spin themselves a few times in the air. The Stenella found near Hawaii

also practice this maneuver.

Stenella attenlll1t!l

Figure I-H. Stoll'lla lIitL'll!lata, known as the white,: ttl.'d dolphin, named by Gray in 18-16.

OTHER CO\(\W:-\ ~.\\IE: Slender-beaked porpoise.

MORPIIOLOCY: The triangular dorsal fin of thispecies is medium size but low, is located at the middle of the body, and e.:ms bachvard. The flipper reaches a length of about hvo-fiftcenths of the body length, is sharp, and curves b~lckward. '{ales reach 2.0 to 2.1 m ill kngth. The total spread of the tail flukes is about two-ninths of the body kngth. The caudal part is more slender than that of blue-white dolphin .md resembles the common dolphin.

The body color of slender-heaked porpois ·s is vcry distinctive. Except on the dors.ti ..:kin, which is sted hIlI<" and t. .c rostnlnl, gray color domi­nates. \Vhen the animal is viewed laterally. tl ' dark portion appears to begin at the midule of the frontal heau and u m tinlle as far hack as the posterior end of the dorsal fin. The hOllndary hdween the light and dark regions forms ;1Il arch which runs from the III \\- hole to the posterior edge of the dors;t\ fill_ :\ charcoal-gray stripe runs fn1 11 the base of the tail flukes to the anterior edge of the dorsal fin hase. The rostrum is dark in color. Except for a white hand along the axis on .:!.... abdomen, the rest of the body is gray.

In females, the skin around the mammill.l is slightly lighter in color. The slate gray color of the lower jaw extends .is far as the throat and in a dotted chain to the corner of the mouth. Tl:e bteral edge of the lower jaw is hlaek, but the tips of both jaws arc \\" l ite. There are many small spots, (rray in the dark portion of the ho(ly ami white in the lighter portion.

~,..,.-------l{I,~---~-"""'---~)\f,f ammals of the Sea

There are no spots along the axis from the chest to the anllS or along the axis of the dorsal side.

The flippers, dorsal fin, and tail flukes are all black but lack the spots. A black stripe which is less pronounced than that on the common or blue­white dolphins nIns from the anterior edge of the flipper to the comer of the mouth. The eye is encircled with a black ring from which a black line stretches fonvard to join the black portion on the rostmm at a point above the comer of the mouth. \Vhen animals are alive, their dorsal skin reHects the light and appears purplish blue or very dark green while the abdominal skin, particularly that of pregnant or breeding indiviuuals, shows pinkish color. A gray line runs to the boundary between the rostrum and foreheau from each side of the blowhole.

The vertebral fommJa is C7 + Tl5-16 + Ll&-19 + Ca37 = 78. The first two pairs of ribs are two-headed, and five pairs are joined to the sternum. The rostmm is ,lbout 2.:2 times as long as it is wide. £\·e11 though the rostmffi is quite long, the large wiuth between the preorbital joints keeps the ratio of rostnIlll length to width rebtivcly small. The condylo­basal length is slightly ovcr twice the skull wiuth. The rostnnTI length is about .55 percent of the condylobasal length. The flipper has fivc fingers, thc bones of which are I: 2, II: 9, III: 7, IV: 3, and V: 1-2. The dental fo rIll u la is 1 ~:H DISTHlBliTIO:>J: Besitles the holotype, only a few specimens of this species have c\·cr hecn collected. One was taken along the \\-"Cst coast of South Africa by the Atlantide, an exploratory boat of Denmark, and SOme were taken at the west coast of [Zll Peninsula, Japan. [n 1<)6.'3, onc was captur <l ncar Ha\vaii. Judging from such collections, this species may hc present but not abundant in both thc Atlantic and Pacific.

Ih:L.\TED SPECIES: There arc scvcral groups which have color pattf'fIls which closdy res('I111>lc thosc of this species. Each has somc particular characteristic, hut with further stlldy some of those groups may be com­hined.

Stcllclla plagiodon

--.~~ h;.I>.~ ., ----------- -~-.~

Fi~llfe l-l5. Stcndlll piagioc/ol1, knO\\l1 as the spoiled dolphin. named hy Cope in IBG6.

General Biology 87

MORPHOLOGY: The maximum adult length is about 2.2 m. The body of the spotted dolphin resembles that of the white dotted dolphin in shape and color but the high forehead is more like that of the blue-white dolphin. The dorsal body is steel blue though slightly lighter than that of white dotted dolphin. There is no white color on the rostnlln. The yentral skin is mostly light brray. There are many gray or steel blue dots scattered on the light skin and white or light gray dots on the dark skin. The dorsal fin is not large. The flippers, the uorsal fin, and the tail flukes all bck dots. The length of the rostmm is less than two-thirds of the condylobasallength. The dental formula is :I ':}+ The total number of the vertebrae is sixty­eight to sixty-nine.

DISTRIBUTION: Spotted dolphins are not abundant and are found mainly in the Atlantic Ocean (along the lnited States and in the Gulf of ~Iexico). They are assumed to be distributed along the coasts of South .'\merica and Europe, as well.

Stenella graU11lll1li

,. _ r'

Figure 1-16. StcllI.:lld gm/JIIIlJlli. 1-1 llWII .IS Cra!fIll.III·S porpojw, 1l;I!JlcJ L,' LI)lIl1benr

in 19.34.

~IOlU'1l0LOCY: This species rc.h.hes 2.·1 III ill length. Thc hotly is gellerally dark and contains IlllmerOIlS whitt> or gray dots 011 thc dorsal skin. Doth the dorsal fin and flippers arc ft'bth"l'ly small. Thc length of the rostrtllll is less than two-thirds of the clllldyloiJasal length. Each of thl' jaws has forty-three to forty-scH'1l it'd h Oil each row. Thc n·lati\"c proportion of head to total hotly lencrth is ~Ill;dler than in Stcllclla plarriodoH.

DISll\1UCTIOX: Gralfm;lIl's p1lTpoi-;('s ar' distribllt<'d in th' ('astern tropical Pacific.

J(ammals of tile Sea

Stenella frontalis

Figure 1-47. Stenella frontalis, known as the bridled dolphin, named by C. Cuvier in 1829.

\[OROPHOLOGY: This species reaches 1.8 to 1.9 m in length and resembles the blue-white dolphin in its shape. The rostrum is relatively short. The triangular dorsal fin is at the middle of the body and curves backward at the top. The flippers are relatively large, triangular, and sharp at the end. The total spread of the tail Hukes is about one-fifth of the body length. The rostrum is about four-sevenths of the condylobasal length and about 2.4 times as long as it is wide. The eyes are encircled with black rings from which black stripcs nm forward, joining each other at the junction of the of the melon and the rostrum. A dark stripe runs from the anterior edge of the Hipper to the angle of gape. Exccpt at the head, the boundary be­tween the gray side skin and the (Luk dorsal skin is indistinct. The gray on the side of the body gradually pales toward the abdomen, where it is almost white. The rostrum is black, the lower jaw is slightly paler, and the skin on the throat is gray. The dorsal fin and flukes arc all black. The outer surfaces of the flippers arc hlack, exccpt ncar the tip, the inner sur­faces are gray. The abdomen is con'red with small black dots and the dorsal skin, particula.rly postcrior to the dorsal fin, is covcred \vith grayish white dots. The black anterior dorsal skin, the dorsal fin, and the tail f1llkcs lack dots. The vertebral formula is C7 + T 15 + L19 + Ca3G = 77. There are five to six pairs of two-head cd ribs and twenty-eight chenons. The flippers have five fingers of I: :2-3, 1[: 9, Ill: i, IV: 3, and V: 2. The dental formllla is ~ ;:~ ~ . IIowc\cr, Hall and Kelson (19,59) rcport('d thirty-live to forty­four teeth with the avcrage of thirty-seven to thirty-eight and about se\'cnty vertebrae in total.

DISTmnUTIO~: This species is found in temperate zones of the Pacific, Atlantic, and Indian Oceans.

La:,?cnorl,ynchu .. ,

The genus Lagenorhynchlls was named by Gray in 1S16. Some of its principal characteristics are as follows:

General Biolo~1j 89

27c. 1. Dorsal fin barely cur .... es bac~"ward. 2. Adults less than 3 m long. 3. Rostrum length of skull about two times its breadth. 4. Greatest breadth of skull more than one-half of condylobasal length. 5. Mandibular symphysis less than one-fith of mandibular length.

Lagenorhynchus obliquidens

,

, .

- --- .I I .

Figure 1-18. LagcnvrhyncllllS o/Jliq II idc II S, l-ll()\\"n .IS the Pacific white-sided dolphin, named bv Gill in 1865.

01llEn CO~{~(Q:'I/ N.uli::: Pacific white-stripcJ llolphin.

~IOHPIIOL()CY: ~\lthollgh the rostmm of thi.; , pecies is not as distinct as it is in most species of Lngcl1orhlJ"c1/lls, it CJn nonetheless be disti~guished from the frontal area (or melon). The h\)<!y slims rapidly posterior to the anus and the keels of the tail stock arc qllite distinct from the ventral and dorsal sides, extending straight to the flllk '. The falcate dorsal fin is very hi(Th. The flippers are medillm sil.cu, tri.lI1.,;ul.lr, and broadest at the hase. The tail flllkes, also mcuimn sized. r(';}ch .1 total sprc;ul of abollt one-sixth of the body length. The dorsal slIffacc is hLtck. fading gradually into gray on the side. A gray patch, rescmhlill rT a brushed-on stripe, fllns forward along the side from the back. The H'ntral bouy is white and \vhere it m"crIays with the gray side patehcs is distinctly marked with a black stripe which nllls from the corner of the mouth along the ha'ic of the Rippers to the anus. The dorsal fill is hLICk and is marked on the posterior eJge by a white, sickle-shaped arca. The hl'~HI, the Ilpper jaw, alld tIll' lip of the lower jaw arc hlack, hilt the low~: r jaw is white.

90 .\I ammals of the Sea

The white-sided dolphins caught near Japan are usually 2.1 to 2.2 m long and 'weigh 75' to 90 kg. This species does not reach 2.-1 in length. Each of the upper and lower jaws has twenty-three to thirty-three small but sharp teeth, the round cross section of which has a diameter of about 3 to 4 mm. The vertebral fonnula is C7 + Tl3-14 + L20-2-! + Ca30-3-! = 73-78. The first six pairs of ribs are two-headed. The flipper has five fingers, the bones of which are I: 1-2, II: 6-8, III: 6, IV: 2-3, and V: 1-2.

DISTRIBUTION: This species is found in North Pacific waters north of the temperate zone and south of the Bering Sea. It is abundant in Japanese waters and along the coasts of North America from Baja California to Alaska and is particularly well known off the California coast, where large herds are frequently seen.

ABillIDANCE: The population size of this species near Japan alone is esti­mated as 30,000 to 50,000.

FOOD: Though Lagcnorhyncll/ls obliqllidens appears to prefcr squid, they may also feed on small pelagic fishes.

REPRODCCTlO:-';: Breeding and parturition both occur from spring to summer. At the base of the rostmm, the fetlls sports several tactile hairs which are lost soon after hirth. :\ewborn animals are about 1.2 m long, quite large when the adult size is considered.

BEHAVIOR: Although they often form small herds of twenty to one hundred individuals, ohservations in Japallese waters suggest that herds of hlllldreds or e\'en a thousand dolphins are not unusual.

RELATED SPECIES: Lagcnorhyuclllls (lllstralis, Peale's Porpoise.

LagcnorhYf1c!lIls allstralis

Figmc 1-19. LagcnorhYIlC:llIls flllstralis, knO\ ... n as Peale's porpoise, named. 1)\· P('ale in 18,'~.

~IORPHOLOGY: Peale's porpoise reaches a length of 2.0 to 2.2 m. 'Vhen viewed laterally, the outline of the animal slopes gradually from the top of the beak to the forehead, but the boundary between the rostrum ~md the forehead is clear. The falcate dorsal fin is medium in size and has a long base. The Hippers are relatively small and curve bacl,,·ward. The medium-sized tail flukes have a very deep notch at the center of the posterior edge. The keels in front of the fluke on the dorsal, and ventral sides are very distinct. The dorsal body is charcoal-gray. The ventral body is white, and the breast region is gray. One black stripe runs to the corner of the mouth from the front base of the flippers and another from the posterior base of the flippers. The jaws, the area around the eyes, and the flippers are all black, though the flippers are surrounded by white. The black which encircles the eyes joins the black portion of the head . .A white stripe, resembling a painted area, mns forward to the dorsal fin from each side of the caudal portion of the body. Both jaws have about thirty small teeth on each row.

DISTRIBUTIOX: This species is known only in the waters of southern South America.

Lagenorhynchus supcrcilioSflS

LagenorhY71c1ws superciliosfls was named by Lesson and Gamot in 1816:

:MOHPHOLOGY: This species has been described only from a skeleton from the Cape of Good Hope. The vertebral formula is C7 + T13 + L:20 + Ca33 = 73. The peterygoid is not fixed to the skull The dental formula is 30.:. (I "!Jij"·3u·

LagenorhYl1chflS thicolca

LagcTlOrh'/lIc/IIlS thieolca, known as Gray's white-sided dolphin, was named hy Gray in 18-19.

~[OIll)1l0L()(;Y: Becallse this species was described from only one skull found on the west coast of :\orth America, neither the size nor the color of the body arc known. The skull has forty-five teeth on each row. The pre­maxillary is flat and narrow. The temporal fossae are small and rouno, and the rostrum is lon~1('r than oIle-half of the condylohasal length.

)tommals of tile Sea

Lagenorhynchlls aClItlls

Figure I-SO. Lagenorhynchus aCl/fus, known as the .\tbntic white-sided dolphin, named by Gray in 1828.

~fORPIIOLOGY: Adults reach a maximum length of about 2.7 m. The rostmm is short but distinct from the frontal area. The flippers are located forward on the body, and the high, falcate dorsal fin, which shows a separation in colors, is located slightly anterior to the midpoint of the body. The tail flukes reach abolIt one-fifth to one-sixth of the total hody length. The keels are very markcd in the caudal region, and the dorsal keel continues to the dorsal fin. AltholitTh there are many individual variations in the distribution of colors on the body, the general patterns arc as follows: The boundaries behveen the black dorsal and the white ventral "llrfaccs are vcry distiIlct. A black line rims from the hase of the all hlack flipper either to the corner of the mouth or to the eye. Another hlack line nms from the anus forward to the hlack dorsal portion. The lip of the lower jaw is either white or fringed with black.

The maxillary and premaxillary that form the ro'itrtIm are hoth flat in cross section. 'Vhen measured along the hody Jxis, the temporal fossa is long. The pterygoid is firmly fixed to the skllll. On each row of the jaw, there arc thirty to thirty-four rclatively small, "harp tf'eth which have a cross-sectional diameter of aholIt .5 nlln. The \crtehral formula is C7 + T 1.3 + L l8-22 + Ca:3i)..-1l = /.I)..S2. Six of the fiftf'f'n pairs of ribs are two headed. The phalangeal formula is I: 1-2, II: 10, III: 6, IV: 2-3, and V: 2.

Dls'mm(jllo~: In the Atlantic Ocean, this species commonly occurs south of Greenland, off :\orway (\V'here it is the second most common smal1

~ - -

General Biology 93

cetacean), near the Shetland and Orkney Islands in British waters, and off Cape Cod, Massachusetts. None have been found in tropical seas.

ABUNDAJ.'l'CE: Although an accurate evaluation of population size has not been made, population estimates range from 30,000 to 50,000 animals.

REPRODUCTION: The young are born in spring and summer after a ten­month gestation period. Parturition rarely takes place after midsummer ( Guldberg and N ansen, l89.!).

BEHAVIOR: Lagcnorhynclllls aClltlls form fairly large schools which often include more than a 1,000 individuals. Herds of thirty to forty animals have been reported beached in England.

Lagenorilynclllls crusiger

Figure 1-51. Lagt'llOrhljflclll/s c rll " ;,!!(' r, kflUWIl ,IS C.rtI~igl'r·s while-sided dolphin, named by QIlOY anu Gaimaru in lS~'-

MOIlPHOLOGY: Although LagcllorilYllcllflS crtlsigcr and LagcnorizYllclllls acutus arc morphol()gieall~- silllilar. this animal is smaller in size, reaching only 1.6 to 1.8 m in length. Till' dnr"31 skin to the fluke, the rostrum, and }O\vcr jaw are all hlack . ..\ black hand, occ;ls-;ionally very hroad unoer the dorsal fin, runs from the eye to thL' !Il1ke on the ~ioe uf the hooy. Each jaw has twenty-eight teeth on each side.

"

DISTHIDliTIO:\": These animals arc fOllnd in the South Pacific between 20 S ana the drifting ice zone.

Lagc1lorllYllclllls rrilsolli

LagcllorilYllclltls reiisol/i, kllo\\'11 ~IS \\"ibon's hOllrglass dophin, was named by Lillie in 19 Vi

~fonplIoLOGY: This species, thollgh closely relatcd to Lagcnorhyncllfls cmsigcr, is slightly larger. It has a sharp rostrllm, anti the black banos which rim along both sides of the hody join on the ventral side below the flippers.

94 ~I(/mm(!ls of tlie Sea

Lagenorhynchus fit:,royi

Figure 1-.5:2. Lagc/lorhynclllls fitzroy;, kllOWIl as Fitzroy's Jolphin. \lamed bv \\·atcr­house ill 1836.

~ronpHOLOCY: Although Beddard (1900) statcd that this species might be the same as L!lgellorhYllchus cl"IIsiger they will be treated in this work as two different species. Thc holotype was 1.62 m long. amI Beddard gh·es the range as 1.4 to 1.9 m. The vcry tip of the beak is sharp. On side view, the heak is rounded. forming all arch-Iille that gradlJally shifts to the forehead. The dorsal hlack and the \'entral white Q\·crlap on the sides of the body. The tip of thc heak ncar the cyes, the lip on the lower ja\'.!, and the tail flukes are all black. The flippers and dorsal fin arc dark gray. A gray line, which is hroad(:r than that of Lagenorhynclllls neil/lis. runs from thc hase of the Hipper to the corner of the mouth. The dorsal hlack color projects in two stripes dowll and hachvards in frollt of the dorsal fin. Anothcr small hlack projectioll mns forward at the base of thc tail Uukcs. There arc twt'nty-eight ted 11 on each IIpper and twcnty-four on each lowcr jaw. They arc all cunnI hut sharp at the tips. The pterygoid is fixed to the skull.

\f'SCELL\:\EOl·S: The first specimell en'r collected was speared in St. Joseph nay during the expedition of the Beagle. This specimen was measllrcd hy Charles Darwill and illustrated hy Captain Fitzroy. aft('r whom it was namcd.

HEL:\TErJ SPECIES: Lagl·Twrl,,!w·!I/I') ()/JsrllrtlS (dl\sky dolphin).

AU £

General Biology 95

Lagenorhynchus ObSCtlTtlS ~-- ---

--==~==~ ---~ :::

Figure 1-53. Lagcl1orhYl1chlls obsctlnls, known as the dusky dolphin. named by Gray in 1828.

:MORPHOLOCY: There are thirty to thirty-two teeth on each side of both jaws. Adults reach a maximum of about 2.1 m. Although the body of this species resembles that of La!!.c710rllfj71cllllS aculus or Lagc7Iorllfj71cJms

obliqllidens, the rostrum is longer, and though the dorsal fin is relatively large, its posterior edge is straighter than that of LagcllorllfjllchllS aelltlls or Lagelwrhfjllc!lIls oblifJllidcn.s. The anterior edge of the fin is black while the posterior edge is white. There is a great deal of indi\-idual variation in body color. The following description is based 011 a specimen collected in South America: The dorsum, the Rippcrs, and the tail flukes are all hlack. A thin black stripe runs from the base of the flippers to the eye and white brush-like stripes projcct in hoth directions from a point right hehind the anus. The keels Oil the dorsal and the ventral bodies arc black.

DISTIUllUTIO:-':: Lagenorhfjllclllls obsct/rtls is very common in ;\ 'W Zealand and is distributed in the water near the Falkland Islands off South :\merica. Lillie (191.5) reported that this species lloes not migrate south of .S8 c S.

FOOD: The primary stomach COlltellt of the specimens collected at the Falkland Islands was squid_

llEHAVIOU: After he ohserved thi-; species from the Terra Sora, an explora­tory ship, Lillie (191.5) wrote, "'Vhen we approachcd. the i\ew Zealand coast, a large school camc near the ship and laid arollnd the how, or followed. thc ship as if welcoming or seeing off the ship. They disapp('arcd whell we Ill00Td Ollt of the ,,",Hill waters."

96 Mammals of the Sea

Lagenorhynchus albirostris

Fi~re 1-.54. La r7cnorllyncll!1s albirostris, known as the white-Leaked du1l)hin. 11;lmed DO ·

by Gray in 1846.

~lonpHOLOGY: Although the white portions arc narrower than those of other members of the genus, the body of this species and the white color­ation of the dorsal surface of the beak are typical of the genus. The tail flukes are modcrate in size, and the body behind the anus is slender. The keels are quite marked. Individuals may reach a length of about 3 III hut are generally somewhat smaller. The blubber is rclatively thick. The rmtmm is broad and reachcs a length of about one-half of thc condylobasal length. Thc premaxillary is flat but cOllycxcd slightly toward thc rostrum. The ptyergoid is fixcd to thc skull, and the temporal fossa is oval.

There are twenty-six to twcnty-sc\'cn teeth on each jaw, but there are sometimes more on the upper jaw tlun on the lower jaw. The teeth arc an an'rage of 6 mm in diametcr, slightly larger than thosc of La rrcl1nrliYllclws acrdus. Thc vertcbral formula is C7 + T 14-16 + L2-1-27 + C~d:3-15 == &S-9:3. Thcre are commonly ninety-threc vertebrae. The first fiyc pairs of rik arc two-headed. The flippers ha\'c [i,'c pha1an~es of I: :3, II: 7, II 1: :3, I\': ~, and": 1.

DI:'THIB 'TIO~: The rangc of this species is shift('(1 fllfther north than that of J.a!!,crlOrlllj1IChIiS (lClIlus. They are found only in the northern :\nrth Atl.lI1tic (the J);l\·is Strait, northern :\orway, thc :\orth Sea, and ncar XC\\'follndland) .

FonD: This SfH'cics feeds on squid, octopus, cod, small cod, herring, capelill, antI ~lI1all crtl\lacea. In addition, numerotIS hermit nabs \\'('rc found in the stomach of onc specimen and numerous snail shells in another.

RF.rnODL"CTro~: Parturition is assumed to take place in slimmer and JIlany jl\'·cnilcs abolIt 1.2 1I1 in length han' heen reported heached ill tIl(' later half of the year.

flUL\VlOlt: I [enis of more than 1,.:500 indidduals arc often formcd.

General Biology 97

Tursiops The genus Tursiops was named by Gervais in 1855. Some characteristics

of its members are as follows:

27d. 1. Dorsal fin triangular and bent slightly back"ward. 2. Adults more than 2..! m, less than ·to m long. 3. Rostrum length of skull more than 2.2 times its breadth. 4. Greatest breadth of skull less than one-half of condylobasal length. 5. :Mandibular symphysis less than one-fifth of mandibular length.

Tursiops tnJncatus

/;>"1' ~-. '. ~ : ' • .1" '." • _ •• ' '" - _ . /10 - _ .. _ _ _

__ : ' ••• / " / ,1. . .... . _ •

. ~-:.: .. . . '-' ... , .' ..... ::.j . ~~-- - - --- : ~"r""' .. : _ .... ... ~_ -:! ... ~~_ - _ -

- - '-'<.. '_:,c..c..( __ ':- . =-- - - -- ... =-- ~- .. ~

Figure 1-55. Tllrsi(}r~ trrmeatus, known as til, a!CllOSCU dolphin, narneel hy '[Oil'

tagu in 18 :21.

Olllf:n CO ~[\«):\" ~.\~[E: Dott ll'nos '<1 porpoi ~l' .

:\JOHPIIOLOGY: This species rcaches a length of 2.5 to 3 m. ~lalcs are 10 to 20 em lOIwcr than females. The flippers arc located forward on the body. The dorsal fin is located at the dorsal midkngth, and the posterior end of its base is on the same cross section as the 3nus. The tota l spread of the t3il flukf's is 3hollt one-ninth of the body length. Becallse of the large melon. even though the rostrum of the skull is reLttivcly fang, the aenlal I) 'ak is rather short, comprising ollly olle-twenty-first of the total l)ody len~tl1.

The dorsal surface is blueish steel gray or slate gray and makes a gradual transition to the pale venIT31 surface . .-\ d3rk stripe mns from the hlowhole to the hase of the heak. In addition, there are often one or nvo dark lines runniJlf' from the eye to the rostrtlm.

The vertebral formula is C7 -7- Tl3-U -:- Lt.') + Ca2~'30 = 6.3. Five of

98 )Iammals of the Sea

the thirteen to fourteen pairs of ribs are two-headed. The sternum is in four sections to which six pairs of ribs are joined. There are generally twenty­two to twenty-four chevrons. The dental formula is -}tH. The Hipper has five fingers, the bones of which are I: 2, II: 9, III: 7, IV: 4, and V: 2. The teeth are relatively large (-t to 5 em long, and 10 mm in diameter).

DISTRIBUTION: The bottle nosed dolphin is quite widely distributed. They are the most common species along the Atlantic coast of America and are frequently seen on the European Atlantic coasts. There was even a report from New Zealand. though this author has not yet can finned that report.

FOOD: Fish is the main food item but some squid may also be taken.

BEH .. \.VIOR: Although these dolphins generally form small herds of two to over ten individuals. groups as large as 100 to 500 have been seen. Their actions are rather ~low, they have very little fear of man, and they are easily tamed. Some :lre caught by seine.

Tursiops gilli

Figllrc 1-:56. T"rsi( l; S ~illi. kllown as Gill's bottll"lllhl..'tl dolphin, named hv ])al\ in 1873.

OTHER CO~I~IO~ :\ .\~IE; Cowfish.

~IOII1'1I0LOGY; Ogaw;l ( 19;36) reported that tlli..; species generally r('aches 2.65 m in length and c1o('s not grow long('r than :3.0 m. Hall and K 'Ison (19,59) reported th;lt ther grow as large as .1.5 m in length. ~(y own surveys suggest that they nLl~' ff,;tcll :>.7 III in length.

The body apP(,;lrs to he hasically gray as a whole, with a slightly darker dorsal suface .. ·\ltholl!.!h there is a hlack stripe from the eye forward, it is very indistinct. The H'rtebral forml1la is C7 -L Tl·t + LV> + Ca29 = 6.=J and the first five Ollt of thc fourteen pairs of rihs arc two headed. (This species has Ollt' or two Illore pairs of rihs than r"rsiops '111 IUJlI fl ). The phalangeal formll b is l: 2, II: 9, I II: 7, I V: .I, and V: 2. Thcy ha vc more teeth than Tllrsivps trlll/catlls or Tflrsiops IlIlIlanu. The dental formllla is ~ n·'l:\ '1 IT. ~ .~ .

DISTIUBUTIO~: This species is limitclI to thc Pacific Ocean and is ahllndant in the l\orth Pacific. \Iost of the Tllrsiops which arc callght near Japan

General Bio7ogy 99

and kept in the aquaria and zoos there are assumed to be of this species (although they were once thought to be rllrsiops truncatus).

FOOD: This species feeds primarily on fish but may also take some squid.

REPRODL''CIlOX: There appear to be two breeding seasons, one in spring and one in fall. \Iost females breed and are impregnated in \[arch to ~fay, but those which are not successfully impregnated at this time may breed in autumn. The gestation period is eleven to t\velve months long, and new­born calves are about 1.3 m. \Vhen females are kept in captivity, they tend to delh-er premature cah'es about 1.2 m long which die within a month. \Vhen the calves are as large as 1.3 m in length at the time of birth, howe\-er, they generally sun'ive. \lothers which ha\'c been in captivity for some time and are accustomed to the pool appear to be less likely to abort. In the first year after birth, juveniles grow to over :2 m in length. Females attain sexual mahlrity at an age of four to six years and a length of 2.7 to 2.9 m.

BEHAVIOR: This species is coastal, and groups sometimes appear to become residents of a particular area .. \lthough herds generally consist of from a few to several tens of animals, herds of several hundreds are occasionaH}; seen. They show little fear of humans alld are ea~ily tamed, though perhaps not as easily as Tllrsiops trrmeatus.

The swimming speed is not notably fast. Crui _~ing herds mO\'e at about 7 knots (9 to 1:2 klll/hr) and e\'en ('scaping animals do not seem to exceed .20 knots (:36 km / hr), They frequently follow ships cruising at 10 knots (18 km/ hr) ritling the bow wa\·es. The breathing actions are gcntle. These animals often jump completely out of the water, exposing the entire hody.

LOXf:EHTY: Tllrsiops ai/li prohably live twenty-fh-e to thirty ye;lrs.

RF.L.\TED SPECIES: Tllrsiol's rl/lfWl1Il (Pacific hottlenoscd dolphin).

TllrsioJ1S 111111111111

---~~- --

Figllrc 1-.=57, Tur ,iops mil/an", known as the Pacinc hottll'llmcd dolphin, llamed by Andrews in I()!!.

\[onPIIOLOGY: Althollgh the holotype of this specics was Jcss than 2.3 m long, the size of all other Pacific species of Tursiops would suggest that

100 :\lammaL~ at the Sea

that specimen was not an adult. The dorsal body is slate gray and the ventral body is white. The posterior end of the vomer is wide and the angles at the end are sharper than the right angle which is fonned on the end of the vomer of Tllrsiops gilli. However, the differences between this characteristic of the two species is minor and cannot easily be used to distinguish them. The condylobasal length is at least 10 per cent less in Tursiops nUllanu than in Tllrsiops gilli. Ogawa (1936) described a wrinkle on the eyelid of Tursiops nrwanu that is absent in Tursiops gilli. The posterior end of the ma.xillary which forms the orbital fossa is almost straight, and the bone that constihltes the upper part of the orbital fossa is not thick. The mandibular condyle is relatively small, reaching less than one-half of the height of the mandible at the coronoid processes. The length of squamosal fossa along the body ax.is relative to the condylobasal length is less than that of other species. The dental formula is }tH. DISTRIBUTION: Tursiops nrwanu are distributed in the Pacinc Ocean, particularly in the tropical seas near P~lllama. It is not yet known whether they are found in the western Paci£c. Ogawa (1936) stated, "Tursiops gilli found near Japan should be considered the same species as Tursiops nuuanll, since they closely resemble each other."

Tursiops aduncas - -----------~~~-----~

Figure 1-,58. Tllrsiops aclllll clls, n.lmco hy Ehrenberv in 18T3.

\f I\PIIOLOGY: The rostmm of this species is rather long and slender, but the condyIobasallength is rather short. The vertebral formula is C7 + T13 + L 15 + Ca27 = 62. The palatine has a sharp forward projection which extends beyond the line connecting the last tooth on each side.

DISl11IDUTION: This species has h('cl1 collectcd from Allstralian waters, tIle Indian Ocean, and tlw South Chilla Sea.

Tursiops pan:imanlls

Tursiops parr.;imanllS was named hy Heinhardt in 1888.

\fORPIiOLOCY: Like Tursiops ad,meas, this species has a vcrtebral formula of C7 + T13 + L 1.5 + Ca27 = 0:2, but has a different phalangeal formula, I: 2, II: 6, II: 8, IV: 3, and \': t It h~lS more hones in thc third finger. One

General biVlogy

young specimen was collected from the Adriatic Sea. Liitken (1888 ) discussed the possibility that this species may be the same as Tursiops aduncas.

Tursiops gep/zyrcus Tursiops gcp/zyreus was named by Lahille in 1908.

MORPHOLOGY: This species has fewer vertebrae and a slightly longer rostrum than Tllrsiops trrmcatlls. It was collected from the vicinity of

Argentina.

Tursiops abusalam

Tursiops abllsalll1n was named by Ruppell in 1842.

~fORPHOLOGY: ~fany scientists think that Tursiops abfl.wlam, Tursiops catalania (Gray, 1S62), and Sotlllia gad1l11lu (Owen, 1866) are the same species as Tursiops adrmcas, but further studies on the taxonomy of the genus TIlrsiops are necessary. The vertebral formula is C7 + TU + L16 + Ca26 = 61, and the dental formula is }~ .

DISnuDuTlOX: Tllrsiops llbflSllll1111 is found in the Red Sea.

Sousa

The distinguishing cll\1racteristics of members of the genus SOllsa are the following: 27e.

1. Dorsal fin triangular ;md leans backward. :) Adults lcss than 2 .. ~ m long. 3. Rostrum length of skull more than 2.3 timcs its breadth. 4. Createst breadth of ~kul1 less than olle-half of condyloj,asaJ length. ;). \[;mdibular symphY'Iis JIlore than olle-fifth of manclihular length.

Snu,a I'l/lll/hca

Figure 1-.')9. SOl/sa plrwil). II , !.. I\ uwn as the plllJllb<:olls (lolpliin, Il.ll11cd hy l.llvicr in ltl:!9.

lUi Mammals of the Sea

OTHER CO:\n,lO~ ~.Ul£: Lead-colored dolphin.

~IORPHOLOGY: This species resembles Tursiops giTli in appearance, but the body color is quite pale. The dorsal surface is lead color or light gray, and the abdominal skin is almost white. The maximum girth of the body is about the middle where the dorsal fin is located. The flippers are wide at the base and pointed at the tip.

The beak is long, and the distance from the tip of the snout to the eye is almost one-sixth of the body length, which may reach 1.-1 111. The dental

formula is -H-:H-. DISTRIBUTIO:-';: The plumbeous dolphin is found in the lndian Ocean, near Ceylon, ~ladras , the ~blabar coast of India, and the Strait of ~1abcca. They are belie\'ed to be more pelagic than any other species of the genus Sousa.

RELATED SPECLES: SOllsa chinensis (Chinese white dolphin).

SOllsa chinensis

Sousa chinemis, known as the Chinese white dolphin, was named by Osheck in 176.5.

~IOHPIIOLOC.Y: The hody of this species is generally in)ry. hut the H_'utral skin is slightly pinki::ih. The dorsal fin, Hippers, and Llil illlkes are brownish gray mingled with a little cherry pink. The eyes are bbck. On a specimen whose condylobasal length was 42. CH1, the rostmm W~lS 2.7 em long and 1.5 cm wide at the base, and the skull measured V5 em at the maximum width. The symphysis of the mandihle is rdatiH_:ly Jon:; ahollt one-fifth of the length of the mandihle). Although there arc reportedly thirty-two teeth on each , ide of hoth jaws, one specimcn ('unlincd was ~ ~:g ~ . The \'ertehral fomml:! is C7 + T12 + L10 + Ca:22 =.51 .lnd the phalangeal formula is I: 1 II : 7. Ill: 5, 1\: 3, and V: :2.

OISTIIIBUTIO:\,: The Chincse white dolphill is distrihllted in the South China Sea, mostly from the .-\lI1oy Day to the Canton Ri\-er.

SOllsa borncensis

SOllsa homrcT1sis. knDwn as the Borncan white dolphin. was named by Lydccker in 190 1.

~ ;IOI\PUOLOC.Y: The dorsa I fin is very low and is not c()nC~l\'e on the posterior edge. The base of the dorsal fin extends to\vard the Lti1 flukes and forms a keel. The ('ntire hody is a heautiful glossy white with many gray spots.

DlsnuBuTIO:\,: The I30rncan white dolphin is distributed from the Gulf of Siam to tbe northwestern coast of Borneo.

General Biology 103

Sousa lentiginosa

Sousa lentiginosa, known as the freckled (or speckled) dolphin, was named by Owen in 1866.

OTHER CO~IMON NA~IE: Bolla gadim.

MORPHOLOCY: The dorsal skin of this species is bluish steel gray, and the ventral skin is pale. Many spots of yellow ochre or la\ender color are scattered over the body, and there are vertical stripes on the side. Adults reach a length of about 2.5 m and a weight of around 150 kg. The dorsal fin is relatively small, but its base is long and extends posterior to almost half the distance between the tip of the dorsal fin and the fluke. The flippers are round at the anterior edge and curve backwards at the end. There are about thirty teeth on each side of each jaw.

DISTIUnUTIo:-.l: This species is known from the coast of sOllth India and Ceylon.

Sousa tewr-i

Sousa teus.::;, known as the 'Vest African many-toothed dolphin, was nallled by Klikcnthal in 1892.

\fOHI'I[OLOr.Y: This species reaches a length of 2 .. 1 m and a weight of around l ·tO kg. The blllbber is \·ery thick. The blowhole sticks out in a hlbc-Iike form, making a small hUlllp.

DISTIIIlIUTlO:-.l: These dolphins arc distributed off SeneO'al to the Cameroons of the west coast of Africa.

Steno

The g('IlIlS Stnl(J was named hv Crav in IS·16. Some of the ch,lracteristics ,", . , "

of its memhers arc as follows: 2Gh.

1. Forehead rises from the heak in a gradllal ctln·e. 2Sa.

2. Dorsal fin is triangular and hends backward slightly . . 1. Adllits more than 1.8 hilt less than 2.S m long . . 1. Rostnml length of skull more than three times its breadth. S. Crcat<'st hreadth of skull less than one-half of condylohasal length. 6. \fandihular .c;ymphysis about onc-fourth of mandihlliar length.

~-----------l~04~------------------~~(~a=m~~~~~~~th~e~Sea

Stena bredanensis

,-- -.::::::=- ------ ---

-- --- - ---fi~ re 1-60. StCl10 brcJllTlCnsis, klluwn .is the rough-toothed dolphin, named L~· Les­son in 18~8.

:\JORPIIOLOGY: The maximum b dy length is 2 .. 5 m. The rebtin.'ly tall dorsal fin is located at the middle of the body and leans bac~·ward. The flippers are fairly long (about one-st..'n~nth of the booy length) allli the tail flukes are large, reaching a "idth equal to one-fourth of booy length, :\Jost of the booy is charcoal <Tray or black, but there are irregular white patches on the IInderside. In addition, there :1fe white, pate cherry pink, or iH)ry spots on various parts f the skin. These spots are presllmahly scars left by parasitic protozoa or b;lctl'ria.

Thc skull is ,·ery distinct in'. The rostrum is afmost t,vo-thiros as I()n~

as the condylohasal kngth and U\ l'r :3.1 times as long as it is wide. This hi!o!h ratio results, at least in p.!rt. from thc small sizc of thc intcn al between the premaxillary processes. The Ilundihlllar symphysis is ahout one-quarter of the mandible's len·..:,th. The pterygoid is fixeo to the sku ll. In each jaw, there are twellty to tWt'lIty-s('\"cn fairly large teeth at thc crown of , ... ·hich there arc many \Trtic;t\ fine wrinkles. The \'ertchral forlllu b is C7 + T13 + L 15-16 + Ca.1~:H - G6. Four or fivc pairs of ribs arc two headed and five pairs of ribs are j,)incd to the sternum. Thc flipper has fi\·c fingers, thc bones of which art' I: :3, II: 8-9, IIi£: 6-7, IV: 6, and ": ~.

DISTHIlICTIOX: Hough-toothed dll phins arc dis'trihlltcd in the teIlllwrate seas of the Atlantic, Indian, and \"orth Pacific Oceans. Specimens havc also heen recorded near the H;\waii.lIl Island's, Ja\·a, and the Bay of Bi'l·ay.

C c plllllnrh ynch Wi

The genlls CCIJhlliorhYTIcllIIs W.l.:'i Ilamclt hy Cray 1I1 18·16. Somc of its characteristics arc the following:

General Biology 105

28b. 1. Dorsal £in small and neither pointed nor bent backward. 2. _-\dults less than 1.8 m. 3. Characteristic body color patterns. 4. Inhabit high latitudes of the southern hemisphere.

Cephalorhynchus commersoni

Fi~'tlre I-oLe cplUllorhrplc1l11s COI/Wll'TI ni. l-nown as Commc:rson's dolphin, n.IIllL..J

by L.1et:pcdc in IS04.

OTlIEl1 Co~nlO~ N,nlEs: Piehald poq (li , e. Le Jacobite.

~I nPIIOLO{;Y: This speci('s reaches ;l ICIl':.!th of ahout l.6 m. The rostrum is fairly sharply pointed at the tip. allll its bOllndary with the forehead is indi!)tinct. The dorsal fin is located ~Iightly posterior to the middle of the b dr ;11)(..1 is not pointed at the tip. The hase of thc fin is long. The flippers are rollnd at the end and sOlllewh;lt I.)\ ' ;d in overall shape. Thc Ilotch at the IX sterior edge of the tail fiu kes is not :-.0 distinctivc as in thc other species of Cc..·p!w[orh'jTlc!IIlS.

ThL' pattern of colors is very chaL.lcteristic of this g<"0I1S. Thc heatl and the region from the dorsal fin to tht' flllkes are hoth black and the area between is white. On the underside. thC", skin is black in front of thc flippers, and therc is an oval patch in the throat region. Except for hlack patches :UOlllld the anlls and genital opcnin':.!. thc ahdominal skin is all whit('. The lower surfaces of thc tail flukes and the caudal pedunclc arc black. There are twenty-ninc to thirty small pointed teeth on each side of each jaw.

DISTHIDvTlO~: This species is fOlllld in the Strait of :\lagcllan, Tierra del Fuego, and the Falkland Islallds, off the southern tip of South America.

106 Mammab of the Sea

FOOD: Commerson's dolphin appears to feed on a wide variety of food items, including squids, euphausiids, and fishes. Judging from the appear­ance of the'mouth and teeth, hO\ve,"er, it is unlikely that they feed on large 'animals.

fu:L-\TED SPECIES: Cephalorhynchus headsidei (Headside's dolphin).

CephalorhYllchus headsidei

--~-' - . - -

Figure 1-6:2. Ccplralorlrljllc1l!1s /aCat:;,I;dl.'i, kllown as I1eaviside.·s dolphill , lIamed b\' Cray in 18:28.

~IORPIIOLOCY: Heaviside's (lolphin reaches a length of 1.2 to 1.3 m. The oorsal body is hlack, and the , 'entral skin from the thorax to the anus is white. Except for the absence of white spots above the eyes, the black and white color patterns on the side of the hooy resemble those of the killer whale. \Vhen the animal is vieweo laterally, the rostmm appears indistinct. The hody reaches its maximllm girth midway between the flippers and the dorsal fin. The triangular dorsal fin is located slightly posterior to the center of the hody, is sharp at the f'lId, and docs not hend backward. The keels behind the dorsal fin and the anllS are indistinct. The flippers are small, triangular, narrow, sharp at the eno, and curve on the front edge. The tail flukes are ~mall'. narrow. ano curve backward. Both jaws han' twenty-five to thirty small sharp teeth on each side, ano the lower ja\v extenos beyond the upper.

DISTIUBUTIOX: This spccies is known from cold seas in the southern hcmi­sphere off the Cape of Good Ilopl' of SOllth Africa.

Cephalorhync1l1ls hectori

General Biology

-~~ . -=== s . ~ -. ,~,,~.

Figure 1-63. C eplwlorhynchus ll(:ctori, known as Hector's dolphin.

107

MORPIIOLOCY: This species reaches a length of approximately 1.8 m. The beak is a little more prominent than that of Ceplzalorhljl1chus heat:isidei. The small dorsal fin is located about the middle of the body and is low in profile. The dorsal keel is very low. The posterior and anterior edges of tht.' flippers are almost parallel and the tips are rounded. The width of the relatively small tail flukes is tess than one-fifth of the body length. The color pattern resembles that of Ceplllllorhljrlcllfls hcat"isidci except that 'in this species, the black portion near the flipper is \\ider and the white portion just above it extends to the lower jaw. There are thirty to thirty-two teeth on each side of each jaw.

DISTIllBUTIO::'i: Hector's dolphin is found only in the waters off ~ew Zealand.

Ccphlllorhljuclllls albifrolls

--=:-- - ---- "----

Figmc 1-6·1. C',,!lfl[orllYllchus alhi/ruTu, known as thc white-headed dolphin.

~[()npIIOLOC;Y: The body of the white-headed dolphin is less than 1.3 m long and reaches its maximum girth about one-third back from the tip of the snout. The head is quite slender, and there are thirty-one to thirty-two

108 Jlamnwls of the Sea

teeth on each side of each jaw. The dorsal fin, which is located at the mid­point of the body length, is low and rounded on the end. The tlippers are narrow and curve backward. The posterior edge of the tail flukes, which also curve backward, is considerably concave and marked by a deep notch. In front of the blowhole, the head is white. The white coloration extends behind the eyes. The skin around the blowhole, on the dorsal fin and tail flukes, and around the genital opening and anus are black, and the rest of the body is gray. There are two gray stripes on each side, one running from the base of the flipper forward towards the rostrunl and another nmning forward from the caudal peduncle. Although this species is reportedly common in New Zealand waters, only a few specimens have been seen.

Cephalorhynchus eutropia

Cephalorhyncus eutropia, 1.-nown as the white-bellied dolphin, was named by Gray in 1849.

MORPHOLOGY: The adult body length is about 1.-1 m. The dorsal fin is rounded and the flippers are small. There is a marked curvature in the posterior edge on the tail flukes. The body is generally gray with white spots at the throat, behind the flippers, and on the abdomen.

DJSTIUm;TIO~: The white-bellied dol:phin is a \'ery rare species which has been caught only off southern South America.

SOlatia

The genus Sotalia was named by Grav III lSG6. Some of its principal characteristics are the following: "Be - .

1. Dorsal fin triangular, curves bachvard only slightly. 2. Adults less than 1.85 m long. 3. Hostrum length of skull about 2 . .3 times its breadth . .. 1. Inhabit mainly large rivers in South America and their estuaries.

General Biology 109

Sotalia fludatilis

Figure 1-65. Sotalia fludatilis, knO\\."Tl as the Bulfeo negro, named by Cervais and DeVille in 1853.

OTHER Co~nlON N.-\...\[ES: Buffeo negro, pirayaguara, tucuxi, and Amazon dolphin.

\IOHPHOLOGY: This is the smallest of the cetaceans, averaging 1.1 m and reaching a maximum length of 1.2 m. The body is typically dolphin shaped. The dorsal body is brO\vnish charcoal gray, while the ventral skin from the throat to the anus is cream yellow to ivory. The light ventral coloration projects from the anus to\vard the front of the dorsal fin in two bands. The <..Iorsal fin and flippers are proportionately balanced to the small body. The tail flukes are not \vide (tip to tip) but are quite broad. All the fins are the same color as the dorsal skin.

In one specimen \vhose condylobasal length was 38 cm, the rostrum comprised two-fifths of the skull length and was two-fifths as wiele as it was long. There were thirty teeth on the upper jaw and thirty-one rather sna~gled teeth in a disordered rowan the lower jaw. The vertebral formula is C7 + T12 + Lll + Ca:26 = 56. The first five pairs of rihs are two­headed and joined to the sternum. There arc five fingers, the bones of which arc I: I, II: 8, III; .3, IV: <1, and V: 2.

DISTIULHjTIO:-.f: This species is found :2.000 krn and fmther upstream in the Amazon River and is often found with I Hill geoffrensL,).

Sotafia paUida

Sotalia pallida, known as huffeo blanco, was named by Gervais in 18.5.5.

\IOflPHOLOGY: This species reportedly reaches a length of 1.7 m. Thev resemble buffeo negro in general appearance but have a thicker and short~r