Marine Mammal Notes

Mammal Characteristics  Endotherms – warm blooded. Body temperature regulated internally.  Hair – to retain body heat  Viviparous – live bearing animals. Embryos develop within the mother’s body.  Placenta – membrane that connects baby to mother.  Mammary glands – feed young with milk with milk  Lungs  4 Chambered heart

Pinniped Characteristics  Examples: Seals, sea-lions and walruses  Pinni – “winged”  Ped – “footed”  Thought to have evolved from cats, dogs and bears.  Most live in cold regions  Predators that feed mostly on fish and squid  Paddle shaped flippers for swimming but they need to rest and breed on land.

Pinniped Characteristics, cont’d  Animals are big – less surface area to volume.  Males are bulls, females are cows, babies are pups  Blubber – a thick layer of fat under their skin *used as a food reserve *provides buoyancy *warmth

Sea lions 5 species  Characteristics  Dog-like faces and they “bark”  Use front (anterior) flippers to swim  Rear flippers can be rotated forward so they can walk on land.  Graceful, agile swimmers  Related to fur seals  California Sea Lions – do tricks at Sea World – smart

Seals 19 species  Characteristics  Cat-like faces  Rear flippers (posterior) cannot be moved forward so they have a hard time moving on land  Better swimmers than sea lions – they can dive deeper for a longer period of time.  Examples: Harbor seals and Elephant seals  Elephant seal males can get up to 20 feet and weight 4 tons.

Comparing Seals and Sea lions Seals  cannot rotate rear flippers  Short neck  Swim with rear flippers Sea lions  Can rotate rear flippers  Long neck  Swim with front flippers

Walrus  Characteristics  Tusks are used for defense and to pull themselves up on the ice. If one breaks with more than half remaining, they can regrow.  Tusks are canine teeth.  They live in the Arctic.  Their blubber can weigh up to 900 lbs.  They have inflatable air pouches in their throat  They eat shrimp, snails crabs, clams and mussels  To swim they use their front and rear flippers.

 Whiskers: Act as feelers to suck up bottom invertebrates and clams. Full grown species have approx. 300 stubby whiskers.