Basic Facts about Sea Otters

The heaviest member of the weasel family, the sea otter is also the second smallest marine mammal. Sea otters have the densest fur in the animal kingdom, ranging from 250,000 to a million hairs per square inch, which insulates them and maintains warmth. Unlike other marine mammals, the sea otter does not have a layer of blubber (fat) to help keep it warm.

© Marc Mantione

Diet

Sea otters mainly eat urchins, abalone, mussels, clams, crabs, snails and about 40 other marine species. Sea otters eat approximately 25% of their weight in food each day!

Population

Historically, sea otters numbered between several hundred thousand to more than a million. But due to the fur trade, worldwide numbers plummeted down to a total of 1,000-2,000 in the early 1900s. As of 2009, the three-year running average is approximately 2,800 southern sea otters off the coast of California. There are between 64,600 and 77,300 northern sea otters residing in Alaska, Canada and Washington. There are approximately 15,000 in Russia and less than a dozen in Japan.

Range

The sea otter’s historic range stretched from Japan, along the coast of Siberia and the Aleutian Chain and down the Alaska, British Columbia, Washington, Oregon and California coast to Baja California. Currently sea otters can be found in California, Washington, Alaska, Canada, Russia, and Japan.

Behavior

Sea otters live in shallow coastal waters off the northern Pacific. They are the only mammals other than primates, birds and a few other animals known to use tools. They use small rocks or other objects to pry shellfish from rocks and to hammer them open.

Reproduction

Mating Season: Throughout the year.
Gestation: 6-8 months
Litter Size: Generally one pup, but sea otters can give birth to twins.