A group of seals rests on floating ice in front of Muir Glacier in Glacier Bay, Alaska. Most species of seals have thick skin and a thick layer of blubber—which can be 5-6 inches (11-13 centimeters) thick— beneath the skin. This layer of blubber acts as insulation, and it also provides seals with energy stores for when they are not foraging.
(Photograph shot on assignment for, but not published in, "A Place Apart," January 1984, National Geographic magazine)
