Marine Mammals Intro and Evolution

Characteristics

• feed from the sea

• adapted to spend lots of time in the sea

• mammals (mammary glands, live birth, have hair)

Carnivores

Animalia, Chordata Mammalia

Herbivores

order Sirenia

Dolphin anatomy

melon, rostrum, blowhole, dorsal and pectoral fins, flukes, caudal peduncle

pinniped anatomy

fore flipper, hind flipper, tail

vibrissae

highly sensitive specialized whiskers (on sirenians)

sexual dimorphism

different M v F characteristics

• closer opening to anus = F

Polar Bear

• evolved from brown bears (Canada) in ABC Islands

• ice sheets separated populations and they evolved differently

• now making hybrids with grizzly bears

Pinnipeds

• from land animal

• can come on land to mate, give birth, and protect neonates

• closely related to ursidae (bears)

Puijila darwani

• webbed feet

• walking on land

• canada

• freshwater

pinniped evolution

Enaliaretos

• CA

• adapted to sea

• sexually dimorphic

pinniped evolution

Sea Otter

• in N pacific

• ancestors from Russia (then Alaska)

Sirenians

closely related to elephants

• herbivores

• migratory teeth