The sea otter (Enhydra lutris) is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although it can walk on land, the sea otter lives mostly in the ocean.Sea otters, whose numbers were once estimated at 150,000-300,000, were hunted extensively for their fur between 1741 and 1911, and the world population fell to 1,000-2,000 individuals in a fraction of their historic range.
Ten Facts about Sea Otter
- The sea otter is the largest member of the Mustelidae, or weasel family, and the only one which lives almost entirely in the water.
- Sea otters can live up to 25 years of age, although the average lifespan is 10 to 12 years.
- Although the sea otter is the smallest marine mammal, the average adult can be as large as 5 feet in length and weigh up to 70 lbs. The average length of an adult female is 4 feet and average weight is 60 lbs. At birth, sea otters weigh approximately 5 lbs and are 10 inches in length.
- Sea otter fur ranges from brown to almost black with guard hairs that may be silver, light brown, or black. As a sea otter ages, their hands and necks will lighten until almost white.
- Sea otter fur is the finest of any mammal, consisting of 850,000 to 1 million hairs per square inch.
- Sea otters are social animals who may float together in groups of less than 10 to more than 100, called rafts.
- Sea otters mainly eat benthic invertebrates such as clams, mussels, urchins, crabs, and fish. They must dive to capture their food, sometimes up to 250 feet. Adult sea otters can eat 25 to 30 percent of their body weight per day in order to stay warm.
- A sea otter becomes sexually mature at 3 to 6 years.
- A female's pregnancy usually lasts 5 to 8 months and can have one pup per year. In Alaska, most pups are born during May and remain dependent on their mothers for 5 to 12 months.
- Predators include humans, sharks, bears, eagles (on pups), and killer whales.
