The Sea Otter is the largest member of family Mustelidae, and the smallest marine mammal. Sea Otters are more aquatic even than seals and sea lions, because they mate and give birth in the water. They are tool users, using rocks to pound open hard-shelled prey, such as abalone. Once hunted almost to extinction for their fur, but now protected, they have made a comeback. This has stirred controversy where their predation on abalone, crabs, clams, and sea urchins affects shellfisheries. Ecologists are beginning to understand the larger, long-term role they play in shaping the marine environment, by eating creatures such as sea urchins. Sea urchins feed on and if unchecked, can destroy kelp. Vast underwater kelp forests are at the base of the coastal food web and also provide shelter for countless organisms.

Adaptation: In the sea otter (Enhydra lutris), adaptations to crushing marine invertebrates mark the skull through its powerful chewing muscles, which leave muscles scars in the form of raised ridges of bone and a rough surface texture. Note also the large, flat cheek teeth.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account
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