a mammal adapted to live in the marine environment and dependent on the ocean for food.

Mammals that live permanently, or spend part of their day in the water. Because they evolved from land-dwelling mammals, they have special structural adaptations to allow them to live in water (though they breathe air).

Any mammal that (1) is morphologically adapted to the marine environment (including sea otters and members of the orders Sirenia,, Pinnipedia, and Cetacea), or (2) primarily inhabits the marine environment (such as the polar bear); and, for the purpose of this act, includes any part of any such marine mammal, including its raw, dressed, or dyed fur or skin.

Molluscs