A sea otter floating on its back

Sea otter

Sea otters are one of the largest otter species. Rarely coming ashore, sea otters spend most of their time in the kelp forests off the west coast of America, Alaska and Russia. To keep warm they have the densest fur of all mammals but no insulating body fat. When resting or sleeping sea otters float on their backs wrapped in kelp and often holding paws with another individual so they don't drift apart. Stones are used as tools for dislodging and cracking open molluscs.

Did you know?
Sea otters play an important role in protecting kelp forests from grazing sea urchins.

Scientific name: Enhydra lutris

Rank: Species

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The Sea otter can be found in a number of locations including: North America, Russia. Find out more about these places and what else lives there.


The following habitats are found across the Sea otter distribution range. Find out more about these environments, what it takes to live there and what else inhabits them.


Discover what these behaviours are and how different plants and animals use them.

Additional data source: Animal Diversity Web

Conservation Status


  1. EX - Extinct
  2. EW
  3. CR - Threatened
  4. EN - Threatened
  5. VU - Threatened
  6. NT
  7. LC - Least concern

Population trend: Stable

Year assessed: 2008

Classified by: IUCN 3.1

Sea otters up close

a otters are the smallest marine mammals and also one of the most endearing to humans. Their thick fur makes them look like plush toys, but was almost their downfall during the mid 1700s and 1800s when fur hunting sent their populations spiralling downwards. Their numbers are recovering, but even though the fur hunters have gone, they now live under the constant threat of oil spills.


Unusually for a carnivore, sea otters have large, rounded back teeth. The reason for this is their diet: shellfish. Their teeth are ideal for crushing sea urchins, abalones and mussels.

Sea otters swim down underwater, kicking their strong, webbed back feet to stay near the sea bottom. They then use their whiskers to feel about on the sea bed and dig up buried shell fish with their front paws.

Each dive lasts only 30-60 seconds, so they may need to make several repeat visits before they manage to return to the surface with prey. Once they do, however, they have an intriguing technique for opening the shell.


Sea otters are the only fully marine species of otter, and there are three distinct subspecies that spend their entire lives in the seas around California, Alaska or Russia. They are found in coastal waters where the sea is shallow enough for them to dive for prey. Sea otters are also often found in kelp forests because food is abundant and they use the kelp as protection from predators.

Social behaviour

While sea otters are not social animals, they are often seen in large groups called 'rafts'. In Alaskan waters these rafts can number several hundred animals, whereas in California rafts tend to be much smaller.

Congregating in this way may offer sea otters some protection against attack from sharks or killer whales, through safety in numbers. Male and females live apart for most of the year on different areas of the coast, meeting only for mating and separating immediately afterwards.

Interesting feature

Sea otters are one of only a few mammals known to use tools. They use stones to help them get abalones and mussels free from rocks and then to open them.

BBC News about Sea otter

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