Southern Sea Otter

Enhydra lutris nereis

Southern Sea Otter

Enhydra lutris nereis

Other Common Names
California sea otter

Otter Habitat

Other Common Names

California sea otter

At the Aquarium

Otter Habitat

Appearance

Sea otters are among the smallest marine mammals. Male southern sea otters average 64 pounds while females average 46 pounds. Males and females look similar, but females tend to be lighter in color and are slightly smaller. This species has a round head with a short muzzle and blunt nose. They have tiny round ears that close up and fold back when their head is submerged.

Unlike other marine mammals, sea otters lack blubber. They rely on their dense fur coat and elevated metabolism to stay warm. Their fur is dark brown, reddish brown or black. With age their head and neck become more blond or white.

They use their sensitive whiskers and front paws to locate prey. Southern sea otters use the loose patch of skin under their armpits to store their prey while diving. Their broad and flat tail and webbed, paddle-shaped rear feet make them agile swimmers.

Habitat

Marine coastal areas including rocky and sandy areas along exposed outer coasts; protected areas like bays and estuaries.

Diet

Marine invertebrates including sea urchins, crabs, clams and snails

Life History

Sea otters are social animals and tend to rest in groups. They use complex communication consisting of head jerks and calls. They spend most of their life at sea, but close to shore.

For the most part, males and females are separated throughout the year except for when it is time to mate. Mating occurs throughout the year. Females are pregnant for 6 to 7 months before giving birth. In California, most births occur between December and February. Female southern sea otters typically give birth to one pup.

A pup is completely dependent on its mother at birth and is unable to swim until it is 2 months old. The pair tends to be in constant physical contact with the pup protected on the belly of its resting mother. The pup is weaned off milk and begins to consume solid food when it is about six months old. The female-pup bond lasts for about 1 year; during this time the young sea otter learns what, where, and how to eat.

Females begin to have pups once they reach 3 to 5 years of age while males reach maturity at 4 to 6 years of age. In nature, female southern sea otters live for 15 to 20 years while males tend to live 10 to 15 years.

IUCN Status

Endangered

Ecosystem & Cultural Importance

Southern sea otters are keystone species and efficient predators, playing a fundamental role in the natural food web. They keep coastal ecosystems, like kelp forests and seagrass beds, in balance.

Southern sea otters, like all sea otters along the North Pacific rim, were hunted to near extinction during the fur trade of the 1700s and 1800s. They are now protected under the Endangered Species Act, Marine Mammal Protection Act and California state law. With federal protections the southern sea otter population has grown slowly.

Found along California’s central coast from San Mateo County to Santa Barbara

Sea otters were historically present along the Oregon coast, but due to the fur trade there is no current population living in Oregon.

Occasionally individual sea otters will be observed off the coast of Oregon, most of which are northern sea otters who come down from Washington’s coast.

There are efforts being made to reintroduce sea otters to the Oregon coast.

An average adult sea otter must eat 20 to 30 percent of its body mass in food each day.

To keep themselves from drifting while they rest, southern sea otters will often wrap themselves up in kelp or seagrass.

Sea otters use tools (typically a rock) to break open hard-shelled prey.

With an estimated 600,000 to 1,000,000 hairs per square inch, sea otters have the densest fur of any mammal. Clean fur is critical for their body temperature regulation so southern sea otters spend many hours a day grooming themselves.

Did you know? I’m adoptable!
Learn More

Citations & Other Resources

U.S. Fish and Wildlife Service. N.d. Southern Sea Otter. https://www.fws.gov/species/southern-sea-otter-enhydra-lutris-nereis

Doroff, A., A. Burdin, and S. Larson. 2021. Enhydra lutris (errata version published in 2022). The IUCN Red List of Threatened Species 2021.

Allen, S. G., J. Mortenson, and S. Webb. 2011. Field guide to marine mammals of the Pacific Coast : Baja, California, Oregon, Washington, British Columbia. University of California Press.

Back to All Animals

Southern Sea Otter

Southern Sea Otter

Other Common Names

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

Contact Us

Subscribe to E-Newsletter

About Oregon Coast Aquarium