These large otters live in the so-called "kelp forests" - dense areas of seaweed - and rarely come ashore, floating on their backs when not swimming. Sea otters live in groups known as rafts, and are well-adapted to their marine existence.
Sea otters live in the cold coastal waters around the northern Pacific Rim. They do not need to come on to land to survive, but often do. Sea otters do not have thick blubber under their skins for insulation. Instead, they rely on a layer of air trapped by their soft fur to insulate them against the cold. Their fur is very thick, with an undercoat that traps air close to the body, aiding their buoyancy as well as keeping them warm. Sea otter spends a lot of time and effort on grooming its dense, glossy fur because the fur's insulating and waterproof qualities are lessened if it becomes unkempt. Pollution, such as oil in the water, can reduce the fur's ability to trap air, and otters may die of hypothermia as a result.
Sea otters can swim very well, diving down in search of food. The otters spend a minute or two at a time underwater, collecting food such as shellfish and urchins. They then float on their backs to feed. They smash the hard shells against stones to get at the soft meat inside, using their chests as tables. Females carry their young on their chest when resting, and leave them floating on the surface while they are diving underwater.
Sea otters are active during the day. At night they wrap themselves in kelp before going to sleep to prevent themselves from floating away. They sometimes put their forepaws over their eyes while sleeping.
Sea otter' fur comprises 100,000 hairs per 1 sq cm (0.15 sq in), making it the densest fur of any mammal. This keeps the animal warm in the cold ocean.
Sea otters live alone and only tolerate each other when mating. A male will defend his territory, but fights are unusual, since most disputes are settled by splashing and vocal contests. Breeding occurs all year round. Pups are carried on the female’s chest for about two months, when they begin to feed themselves. They are independent by the time they are six months old.
Distribution: Inshore areas on both sides of the Bering Sea, and around the Aleutian Islands between Russia and Alaska, extending down as far as California in the USA.
Habitat: Temperate coastal waters up to 20 m (60 ft) deep and less than 1.6 km (1 mile) from shore.
Weight: 14 - 45 kg (31 - 99 lb); males are heavier.
Length: 68 - 163 cm (27 - 64 in).
Maturity: 2-5 years.
Gestation Period: Up to 270 days, as embryonic development may not begin straight after fertilization.
Breeding: 1, occasionall 2; weaning takes 6 - 12 months.
Food: Molluscs, clams, sea urchins obtained from the sea bed, and fish.
Lifespan: 10 - 20 years in the wild; up to 28 in captivity.
The legs are very short. The front legs are used for holding food, like a pair of hands.
These sensory hairs are prominent around the mouth and above the eyes.
Sea otters are dark brown overall, with paler fur on the head.
The ears are very small and set low down on the sides of the head.
Sea otters anchor themselves in among beds of kelp so they will not drift off in the current when sleeping.