A large marine mammal (family Odobenidae) with a very heavy body, large, stiff whiskers, and upper canine teeth enlarged into long tusks used by males for fighting and asserting dominance and by both sexes for keeping holes in the ice open and hauling themselves out of the water. Walruses occur in the Arctic and sub-Arctic, in shallow water and on ice shelves, and feed mainly on bivalve molluscs.