Pacific Walrus

From USFWS National Wildlife Refuge System:

There are two subspecies of walrus: The Pacific and the Atlantic. This photo from Togiak National Wildlife Refuge, AK, shows a Pacific walrus. During the icy winter, walrus herds huddle together, resting on ice. If it gets too cold, they go into the water, often warmer than the air. A walrus uses its tusks to chip the edges of a breathing hole in the ice. They also use their tusks to help haul out of the water. Walruses spend a third of their time on land or pack ice and the other two thirds in the ocean. Both males and females have tusks; the male has longer tusks that are wider in proportion to their body than those of the female. 
About Togiak Refuge: http://www.fws.gov/refuge/Togiak/