On a large animal, there an estimated 650,000 hairs per square inch. Natural oils in a sea otter's fur repel water and trap tiny air bubbles, providing a layer of warm air between the otter's skin and the harsh elements of its environment. They groom by rubbing fur with their forepaws. Their strong claws comb and rake the fur. Then they roll and whirl in the water to smooth their fur.
Sea otters sleep, rest, and usually swim on their backs.
California sea otters spend almost all of their time in the water. Alaska sea otters often sleep, groom, and nurse on land. Because they rely on their dense fur for insulation from the chilly ocean water, sea otters are particularly vulnerable to the detrimental effects of an oil spill. If a sea otter swims into an oil spill, the fur becomes soiled and loses its insulating qualities, allowing water to penetrate to the skin and causing hypothermia and ultimately, death. Busch Entertainment Corporation.