Sea otter in Morro Bay, courtesy of John Calambokidis
10 – 15 years
5 lbs (2.3 kg)
10 in (0.3 m)
ADULT FEMALE FACTS
60 lbs (27 kg)
4 ft (1.2 m)
ADULT MALE FACTS
70 lbs (32 kg)
5 ft (1.5 m)
Sea otters are the largest member of the weasel family, and the smallest marine mammal. They have paw-like front limbs with “pockets” that help them hold food while foraging, and they sometimes use rock “tools” to crush shelled prey.
Sea otters were heavily hunted for their thick, luxurious fur, and were nearly extinct in some areas along the Pacific Coast by the early 1900s. With protection, the populations are recovering. Today there are thriving populations along the central California coast and in Washington and British Columbia.
Look for sea otters near coastal kelp beds. You might see them resting on their backs, snacking on fish or shellfish. Look closely and you might see a baby resting on its mother’s stomach while she floats, or tucked into a kelp bed while she hunts.
Sea otters are swift swimmers. Watch for them diving and surfacing with their prey.
Sea otters are social animals and raft together in groups of a few dozen to hundreds of animals. Look for rafting groups!
Though sea otters spend most of their lives at sea, they occasionally haul out on shore. If you do see a sea otter on shore, watch from a distance and avoid disturbing its rest.
Watch sea otters year round on the central California coast, from Morro Bay to Monterey.
In Washington, look for otters along the Olympic Coast at sites like La Push, Rialto and Ruby Beach, and in the Strait of Juan de Fuca at Shipwreck Point and Snow Creek.
In British Columbia, watch for them at sites along the Pacific Coast like Uclulet and Tofino.
There are three subspecies of sea otters, two of which are found in the United States.
- The Southern, or California sea otter (Enhydra lutris nereis) is rare and declining at a disturbing rate.
- The Northern sea otter (Enhydra lutris kenyoni) is found in Washington, Alaska and Canada, and populations are growing on the Pacific Northwest coast. They prefer to live in rocky coastal areas and can be viewed in sites along The Whale Trail such as La Push and Neah Bay.
- The third subspecies, the Russian sea otter (Enhydra lutris lutris), is found in Russia and Japan.
Sea otters in Morro Bay, courtesy of City of Morro Bay
All sea otters lack insulating blubber, and rely on their thick fur and high metabolism to maintain body heat. Sea otter fur is the thickest in the world and can have up to one million hairs per square inch. This fur insulates the body by keeping a layer of warm air between the outer surface and skin.
Sea otters spend much of their day foraging for more than fifty kinds of marine invertebrate prey including mussels, clams, abalone, octopuses, crabs and sea urchins. They burn calories at three times the rate of humans and must consume 20-30% of their body weight daily.
Sea otters are monagamous and become sexually mature at 3-5 years old. Mating occurs year round. A female otter is pregnant for about eight months and usually gives birth to a single pup weighing 3-5 pounds. Female sea otters are generally excellent mothers while males don’t participate in rearing the pubs. The mother nurses the pup for 6-8 months and averages one new pup every 2 years.
Sea otters are normally seen swimming or resting on their backs, but when moving rapidly, will swim on their bellies.
- Sea otters rarely go onto shore in contrast to their smaller cousins, the river otters, who spend about half their time on land and can live in either fresh or salt water ecosystems.
- Surface eaters, sea otters use their powerful forepaws and jaw muscles to crush prey.
- They can dive up to 300 ft and remain underwater for up to five minutes to hunt for food. Mothers may leave their pups tucked between kelp fronds while they dive for food.
Sea otters are social animals, and gather in rafts (groups) ranging from a few dozen to over one hundred animals. Rafts are sexually segregated as females avoid male feeding areas.
Hundreds of thousands of sea otters once lived along most of the Northern Pacific coast before traders hunted them nearly to extinction for their thick, luxurious pelts. By 1911 fewer than 2,000 otters remained worldwide.
In the 1960s and 70s sea otters from Alaska were relocated to sites along the coasts of Washington and British Columbia. Today there are currently over 1,000 sea otters living on Washington’s outer coast and the western Strait of Juan de Fuca.
The otters are still facing conservation threats, however, and California sea otters are listed as threatened under the Endangered Species Act (ESA).
Oil spills are the most serious modern concern. When sea otters are exposed to oil it destroys the insulating properties of their fur and contaminates their food.
Commercial fishing gear including gill nets can ensnare otters and commercial over harvesting of invertebrates (e.g., abalone and sea urchins) may threaten their habitats.
Sea otters are also at increased risk of diseases and parasites contracted from animals on land. One way to help is to bag and dispose of cat litter instead of flushing.
Sea otters are also at risk from people who want to watch them! Kayakers and beach-goers can get too close and disturb resting or rafting otters, costing them energy. On the California coast, Sea Otter Savvy teaches people how to watch otters without disturbing them. Check it out!