Walrus colony. The walrus (Odobenus rosmarus) is a large flippered marine mammal with   prominent tusks, whiskers, and bulkiness. Adult males in the Pacific can weigh more than 3,700 lb and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic bivalve mollusks to eat.