Marine Mammals Review

Marine Mammals ReviewChapter 6The basicsMarine Tetrapods4 limbsBreathe air with lungsTerrestrial ancestor species

Reptiles, birds, mammals + 1 species of frog in Asia

Identifying Marine MammalsPart 1 of testYou will be identifying BY ENGLISH, COMMON NAME, not latin species name.Beluga Whale

Blue Whale

Dolphin

Humpback whale

Manatee

Orca (Killer Whale)

Sea Otter

Sea Lion

Seal

Walrus

Part 2: How do mammals live in the ocean?FYIFossil and DNA evidence shows that the ancestors of ocean mammals were LAND mammals.Traits of ALL Marine MammalsViviparous (internal nourishment and development of fetus)Body hair (on many but not all)Mammary glandsSpecialized teeth (type of teeth corresponds to type of food)External opening of reproductive system DIFFERENT from external opening of digestive system

PinnipedsFin footed mammalsCarnivores Walrus, seal species, sea lion species

Only one species of walrusSeals swim w/ rear flipper for powerSea lions swim w/ front flippers for powerManatees + Dugongs

Paddle like tailsNo pelvic limbsHerbivoresShallow tropical oceansCetaceans (whales)No pelvic limbs (do have remnants of pelvic bones in skeleton!)No body hairDorsal blowholes for breathingSwim w/ horizontal tails for powerBaleen- adaptation for filter feeding in some whales Toothed whales- carnivores

Breathing Hypoxia- state of small amounts of oxygen in the bodyMust reach surface of water to breathe.Amount of time spent underwater between breaths varies based on speciesRapid exhale-inhale pattern at surface then hold breath while underwater called APNEUSTIC BREATHING PATTERNLungs collapse from water pressure in deep dives- marine mammals can handle this!

Dont memorize, but be impressed!ANIMALMAX KNOWN DIVING DEPTH (m)MAX KNOWN DURATION OF TIME UNDER WATER (min)Human676Dolphin53512Sperm whale3000138Manatee6006Sea otter232.3Elephant sealMale 1530, Female 1273Male 89, Female 120@ ~100 meters under water the lungs collapse completely HOW???Oxygen forced out of lungs as they collapsestore oxygen in red blood cellsHave more red blood cells than humans

CommunicationSound! They sing to each other.Humpback Whale "songsFor reproduction and huntingBehavior- watch each others movements and move in appropriate response.Dolphins play and hunt in groupsOrca's use sound and visuals to hunt together

ReproductionSexual reproductionLive birthBabies must be able to swim with mom immediatelyMilk often has very high fat content to help babies grow fastTime the mothers spend with baby varies greatlymother and calf gray whale Baja Mexico

FYI Newborn gray whale ~16ft long, compared to mother ~49ft long!Part 3: Mammals in the North and South PolesChapter 12This weekFriday Starting Thursday, ending Friday we are watching the Blue Planet episode about the North and south Pole ecosystemsNorth and South Poles are VERY different!

NORTH: Arctic MammalsPolar bears, harp seals, hooded seals, ringed seals, walruses, gray whales, killer whales, beluga whales, narwhals

Adaptation: Milk FatMilk produced can be up to 60% fat so the baby gains weight quickly.Cows milk 3-5% fatNeeded because newborns do not have enough fat and fur to stay warm on their own.

Hooded Seals:Baby weaned after 4 days!Adults need to maintain large amounts of blubber/fat in order to survive in the cold water/air.Adaptation: Migrating animalsCold water contains more small organisms to feed on than warm water Gray Whales migrate 18,000km per year:Summer near Bering Sea (lots of food)~September leave and start swimming southJanuary-March near Baja, Mexico (calves born there)~April leave and start swimming north again

Time on Land v. in waterCommon for sea mammals to give birth OUT of waterWHY???What common traits do you see in the seal pups below? (cute doesnt count!)EXCEPTION: Cetaceans

Mating Areas on landEXAMPLES: Walrus leksLek- arrangement where males pick a spot and show off, females get to decide which male with mate with

FYI walrus gestation= 15 months! Baby spends about 1 year living off milk from mom.

walrus on russian coastWhy are polar bears considered sea mammals?Ursus maritimusHunt on sea iceWill swim long distances for the next meal

Polar bearsPolar bear video (on DVD)https://maps.google.com/maps?q=churchill+canada&ie=UTF-8&hq=&hnear=0x526fd949c8f9f537:0xd10c44d8423762dd,Churchill,+MB,+Canada&gl=us&ei=bOomU-uMIIfF0QGCi4GgCA&ved=0CKkBELYD

YES, polar bears have black skin. WHY is that useful?Polar bear fur is not actually white, but nearly see-though. (like a dusty window)How Baleen Whales EatSkimmingEngulfmentGray whales have short baleen therefore a different way of feeding

Toothed Whales in Arctic

All carnivores

Living in groups called pods And the strange animal award goes toTHE NARWHALEat fish and squid in deep arctic waters1 tusk on males(left incisor tooth)Can sense salinity, temperature, and pressure of water!

Adaptations for HuntingEcholocation (like sonar that submarines use)Works for schools of fish, not good for mammals or individual fish

Vision and Brute forceWorks for individuals or small groups of hunters going after other sea mammalsOrca hunting video shown last week

SOUTH: Antarctic MammalsWeddell, crabeater, leopard, elephant sealsHumpback, orca, minke, fin whales

For the most part animals in the antarctic require similar adaptations as those in the arcticNeed to survive cold air/waterNeed to eat enoughNeed to avoid predatorsAdaptation: teethTeeth are designed for the animals specific prey speciesSmall or large teeth or baleen

I hope the penguin moved after this picture was taken!Surprising uses of teethWeddell seal uses teeth to scrape open an air hole in ice. Teeth become smaller and duller over timeAnimal becomes less proficient at finding preyWeddell seals tend to have shorter lives than other species.

How humans changed Antarctic EcosystemsCold water = many fishOverfishing and whaling in last 100 yearsFewer larger mammals and more smaller mammals

Example: ~30000 blue whales feeding in 1929, ~2000 blue whales feeding 2010

Remember the moral of Happy Feet!The Antarctic Food chainDepends on krillTop predator is IN the water: Leopard Sealleopard seal hunting

Toothed whales All are migrating animalsHere Killer Whales mainly eat sealsSperm whales are most widely distributed whales on earth

Think Moby Dick.Final Thought QuestionWhy are the arctic and antarctic ecosystems vital to the entire world even though they have fewer types of organisms than other areas?