Sea Otter
Enhydra lutris
The largest member of the weasel family, the sea otter is also the 2nd smallest marine mammal. Sea otters have the thickest 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.
Length California sea otters: 4 feet; northern sea otters: slightly
larger
Weight 45 lbs (females); 65 lbs (males). Northern sea otters can reach
up to 100 pounds.
Lifespan 10-15 years (males); 15-20 years (females)
Diet
Sea 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 1000-2000 in the early 1900s. As of 2006, the three-year running average is approximately 2,750 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.
Sea otters spend much of their lives in the water and can dive up to 330 feet when foraging for food. They sometimes rest in coastal kelp forests, often draping the kelp over their bodies to keep from drifting away.
Reproduction
Mating Season throughout the year
Gestation 6-8
months
Litter Size Generally one pup, but sea otters can give birth to
twins.
Threats
Oil spills, habitat loss and degradation, food limitation, disease, fishing gear entrapment and conflict with shellfish fisheries. Learn more.
Legal Status/Protection
*CITES, Appendix I, **Endangered Species Act, ***Marine Mammal Protection Act
*Convention on International Trade in Endangered Species of Wild Fauna and Flora, an international treaty with 172 member countries. Appendix I listed species cannot be traded commercially. Appendix II listed species can be traded commercially only if it does not harm their survival.
** The Endangered Species Act requires the US federal government to identify
species threatened with extinction, identify habitat they need to survive, and
help protect both. In doing so, the Act works to ensure the basic health
of our natural ecosystems and protect the legacy of conservation we leave to our
children and grandchildren.
California, or southern, sea otters are listed as
"threatened" under the federal Endangered Species Act (ESA) and "fully
protected" under California state law. The Southwest stock of northern sea
otters in Alaska is listed as "threatened" under the ESA. In Canada, the sea
otter population in British Columbia is classified as "threatened" by the
Committee on the Status of Endangered Wildlife in Canada (COSEWIC).
*** The Marine Mammal Protection Act prohibits, with certain exceptions, the
killing or harassment of marine mammals in U.S. waters and by U.S. citizens on
the high seas. It also prohibits the importation of marine mammals and marine
mammal products into the U.S.
All of the sea otters in the U.S. are protected
under the U.S. Marine Mammal Protection Act.
How You Can Help
- Help sea otters and other wildlife by adopting a sea otter today at our Wildlife Adoption Center.
- Take Action for Wildlife at our Wildlife Action Center.
For additional information
Visit Defenders' Imperiled Species: Sea Otter pages for more information about what Defenders is doing to help.















