Lagamorpha and Rodentia

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Order Lagamorpha

• Two Families– Ochotonidae– Leporidae

• Characteristics– Diastema– 4 upper incisors (this

is how you tell Lagamorphs from Rodents)

Order Lagomorpha, Family Ochotonidae—pikas

1) jugal projects posteriorly almost to meatus 2) no supraorbital process

Family Ochotonidae

• Activity: – Diurnal– Active year round.

• Diet:– Grasses, sedges, thistles,

and fireweed.– Will eat some food on the

spot and store the rest in a pile called a “haystack”.

• Highly territorial – Use vocalizations in

territorial displays.

Ochotona collaris (Collared pika)

• Range: – Alaska – Northwestern Canada– Southwestern Canada– Western U.S.

Ochotona princeps (American pika)

• Range:– Lower BC– Eastern Alberta– Parts of Western

Canada

Order Lagomorpha, Family Leporidae—rabbits and hares

1) jugal projects posteriorly, but not to meatus 2) supraorbital processes

snowshoe hare—Lepus americanus white-tailed jackrabbit—Lepus townsendii

1) no interparietal 2) postorbital processes broad and winglike

Lepus spp. (hares and jackrabbits)

• Activity: – Nocturnal-crepuscular.– Active year round

• Some have white winter pelage

• Generally do NOT use burrows.

• Males fight for females during long breeding season

• Northern species exhibit cyclic fluctuations in population density.

Photo: Flickr

Lepus americanus (Snowshoe hare)

• Range:– Throughout Canada– Alaska– Extreme Northern U.S.

and much of Western and Eastern U.S.

Lepus townsendii (White-tailed jackrabbit)

Photo: Smithsonian Museum of Natural History

Photo: Flickr

eastern cottontail—Sylvilagus floridanus mountain cottontail—Sylvilagus nuttalli

1) distinct interparietal on adults 2) postorbital processes thinner than Lepus

Sylvilagus spp. (cottontails)

• Activity: – Nocturnal-crepuscular.– Active year round

• Pelage does not turn white in winter.

• Some use burrows.• Coprophagous• Range:

– Southern Canada though South America

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Sylvilagus nuttalli (Mountain cottontail)

Sylvilagus floridanus (Eastern cottontail)

Order Rodentia, Family Aplodontidae—mountain beaver Aplodontia rufa—mountain beaver

1) cranium is triangular and flattened dorso-ventrally 2) auditory bullae are flask-shaped 3) cheek teeth with prominent outer projections

Aplodontia rufa (Mountain beaver)

• Activity:– Active day or night

• Diet:– variety of plant

material• Range:

– Southwest BC to Northern California

• Stores food in burrow.– Territorial defense of

burrow Photo: Washington Dept of Fish and Wildlife

Order Rodentia, Family Dipodidae—jumping mice

1) incisors grooved 2) massive infraorbital foramen 3) 4th upper premolar small and peg-like

Dipodidae (jumping mice)• Activity:

– Primarily nocturnal• Profound hibernators

– Usually dormant early fall to mid-spring

– Double weight in fat prior to hibernation, no food storage

• Diet:– primarily seeds, but also

eats fungus, nuts, berries, and insects.

• Normally move slowly but jump when startled– Long tail and large feet aids

jumping• Range:

– most of BC, Canada, and Eastern U.S.

Photo: Animal Diversity Web

Zapus trinotatus—Pacific jumping mouse

1) crescent-shaped fold on upper premolar

Zapus hudsonius—meadow jumping mouse

1) no fold on upper premolar

Zapus hudsonius

Order Rodentia, Family Castoridae—beavers Castor canadensis—American beaver

1) jugal is conspicuously broad 2) long bony tube surrounding external auditory

meatus 3) incisors massive

Castoridae (beavers)

• Activity:– Diurnal and Nocturnal– Active year round.– Semiaquatic

• Paddle-like tail, webbed feet• Form family groups, slightly

colonial.• Monogamous• One of the largest rodents• Diet:

– bark, cambium, twigs, and leaves. Eats aquatic plants in summer.

• Range: – Nearly all of North America

Order Rodentia, Family Erethizontidae—American porcupines Erethizon dorsatum—North American porcupine

1) massive infraorbital foramen 2) incisors massive 3) auditory bullae larger than Castor canadensis

Erethizontidae (New World porcupines)

• Activity: – Largely nocturnal

• Covered with barbed quills. Feet modified for aboreal life

• Diet: – Fall/Winter: evergreen

needles, cambium, inner bark of trees.

– Spring/Summer: buds, twigs, leaves, flowers, berries, and nuts.

– Bacteria in digestive tract capable of breaking down cellulose.

• Range: – North America and Northern

Mexico

Order Rodentia, Family Geomyidae—pocket gophers Thomomys talpoides—northern pocket gopher

1) postorbital processes inconspicuous 2) upper and lower cheek teeth form “8”s 3) nasals do not project anteriorly to incisors

Geomyidae (Pocket gophers)• Activity:

– Almost entirely fossorial

• Live in burrow system• Diet:

– Underground roots, rhizomes, and bulbs.

– Water obtained from food– Food stored underground

for winter.

• Range: – Southern Canada to

PanamaPhoto: Flickr

Thomomys talpoidesGeomys bursarius

Order Rodentia, Family Heteromyidae—heteromyids Perognathus parvus—Great Basin pocket mouse

1) grooved upper incisors 2) inflated auditory bullae almost touch anteriorly 3) delicately built zygomatic arch

Heteromyidae (pocket mice, kangaroo rats, and mice)

• Activity:• Nocturnal• Live in and store food

in burrows.• Do not require

drinking water.• Range:

– Southern Canada though Western and Central U.S. into Mexico

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