Sea otter

(Enhydra lutris)

Habitat and Distribution: Found in rocky coastal areas in shallow waters off Alaska, the Aleutian Islands, the Commander Islands, the northwestern coast of Vancouver Island, Washington, and California.

Size: 4-5 feet long including the tail; 50-100 pounds. Males are larger than females.

Wild Diet: Fish, sea urchins, crabs, clams, mussels, snails, squid, octopus, and abalone.

Predators: Sharks, killer whales, eagles, coyotes, and humans

Reproduction: Females usually give birth to one pup every other year after a gestation period of about 6 months. Newborn pups weigh 3-5 pounds and receive 6-9 months of maternal care. While a mother is foraging, she may wrap her pup in kelp at the water’s surface to keep it from drifting away.

Behavior: Sea otters are social animals. They may live in groups of 20-100 called “rafts." These groups are sexually segregated; females avoid males except to mate and young males form bachelor groups. Adult male otters maintain territories. Females may come and go through these territories, but the territory holder aggressively excludes male outsiders. Sea otters communicate with a variety of vocalizations including squeals, screams, coos, grunts, snarls, and growls. They spend most of their day resting, searching for food, or grooming their fur to keep it waterproof.


IUCN Status: Endangered

Sea otters have historically been hunted for their dense, waterproof fur. They came close to extinction at the turn of the 20th century but are now protected by the International Fur Seal Treaty, the US Marine Mammal Protection Act, and the Endangered Species Act. In 1989, the Exxon Valdez oil spill killed about 5,000 individuals. Sea otters are also threatened by parasites and infectious diseases, thought to reach the ocean via storm drain runoff. Both the Northern and Southern subspecies (Enhydra lutris kenyoni and Enhydra lutris nereis) are classified as "threatened" by the Endangered Species Act.

Nellie Stacks Cups

Watch the video!

Nellie is a well-trained sea otter at Point Defiance Zoo & Aquarium in Tacoma, Washington. Watch her practice a special cup stacking enrichment and demonstrate trained behaviors with her pal, Abra.

Did you know?

  • A sea otter can open shells by holding a flat rock on its chest and beating the shells against the rock until the shells break open. Or it may take the opposite approach: holding a shell on its chest and beating it with the rock.
  • Sea otters protect the kelp forest by preying on sea urchins that would otherwise overgraze the kelp.
  • They need to eat about 25-30% of their body weight every day.
  • The sea otter is the largest member of the weasel family (Mustelidae) and the only one that lives almost entirely in water.
  • They have the densest fur of any mammal, with up to 1 million hairs per square inch.