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September 10, 2026Sources cited
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Science & Nature • Animal

Sea Otter

The sea otter (*Enhydra lutris*) is a marine mammal in the weasel family, native to coastal waters of the North Pacific.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated September 10, 2026|2 min read| Fact-checked

The sea otter (Enhydra lutris) is a marine mammal in the weasel family, native to coastal waters of the North Pacific. It is known for its dense fur, use of tools, and role as a keystone species in kelp forest ecosystems. Sea otters were heavily hunted for fur and remain a conservation concern in parts of their range.

Taxonomy and description

Sea otters are marine mammals in the family Mustelidae, with the scientific name Enhydra lutris. They are adapted to life in cold coastal waters and have webbed hind feet, a muscular tail, and exceptionally dense fur.

Distribution and habitat

Sea otters occur along the coasts of the North Pacific Ocean in North America and Asia. They typically live in shallow nearshore waters, often associated with rocky shores and kelp forests.

Behaviour and diet

Sea otters are known for floating on their backs, using tools to open hard-shelled prey, and wrapping themselves in kelp to avoid drifting. Their diet includes sea urchins, mollusks, crustaceans, octopuses, squid, and fish.

Conservation

Sea otters were hunted to near extinction during the fur trade. While populations have recovered in some areas, others remain vulnerable, and conservation status varies by region.

Key facts

  • Sea otters are the heaviest members of the weasel family and one of the smallest marine mammals.
  • They rely on extremely dense fur rather than blubber for insulation.
  • Sea otters live in shallow nearshore waters and often forage on the sea floor.
  • Their diet includes sea urchins, mollusks, crustaceans, octopuses, squid, and fish.
  • They are considered a keystone species because they help maintain kelp forest ecosystems.
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Canadian context

Sea otters occur in British Columbia, where they were reintroduced after being extirpated locally. They are a well-known species for Canadian marine conservation and coastal ecosystem management.

Frequently asked questions

What is the scientific name of the sea otter?
The scientific name is Enhydra lutris.
Where do sea otters live?
They live in shallow coastal waters of the North Pacific, including parts of Russia, Alaska, British Columbia, Washington, and California.
What do sea otters eat?
They mainly eat marine invertebrates such as sea urchins, mollusks, crustaceans, and also eat octopuses, squid, and fish.
Why are sea otters important to ecosystems?
They are a keystone species because they help control sea urchin populations and support kelp forest health.
How do sea otters stay warm?
They depend on very dense fur for insulation instead of blubber.
Are sea otters endangered?
Their status varies by region, but some populations are considered threatened or endangered.

References

  1. National Geographic Kidshttps://kids.nationalgeographic.com/animals/mammals/facts/sea-otter
    Supports: Scientific name, diet, lifespan, size, and historical overhunting
  2. Marine Mammal Research Unit, University of British Columbiahttps://mmru.ubc.ca/biology/sea-otter-biology/
    Supports: Subspecies, habitat, range, body size, population estimates, and Canadian conservation status
  3. U.S. National Park Servicehttps://www.nps.gov/places/sea-otter.htm
    Supports: Conservation context and endangered status discussion
  4. Defenders of Wildlifehttps://www.defenders.org/wildlife/sea-otter
    Supports: Keystone species status and North Pacific habitat
  5. The Marine Mammal Centerhttps://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/sea-otters
    Supports: Fur density, body size, and marine mammal characteristics
  6. Alaska Department of Fish and Gamehttps://www.adfg.alaska.gov/index.cfm?adfg=viewing.marinemammals&species=seaotter
    Supports: Habitat, size, and behaviour