Instead, sea otters have the densest fur of any animal. The coat maintains its insulating properties only so long as the fur is kept scrupulously clean. A sea otter spends many hours each day grooming. A soiled sea otter can die of exposure to the cold water within just a few days. Sea otters eat a variety of invertebrates, including mussels, clams, abalones, snails, crabs, sea urchins, sea stars, squid, and octopus.
Otters eat many animals that graze on kelps and therefore protect the kelp from being overgrazed.
Food is gathered with the forepaws and carried to the surface where the otter floats on its back and consumes the prey. They seldom come ashore and can be seen in the kelp where they rest. When sleeping, the otter may wrap itself in kelp fronds so it won't float away. Several otters may raft together in the kelp. They are not sound sleepers and are easily disturbed by any sort of noise or activity.