Sea otter Facts

About the sea otter

Adults weigh 14 to 45 kg, which makes them heavyweights among weasels but small for marine mammals. Unlike most marine mammals, sea otters rely on fur instead of fat for warmth. They can walk on land, yet they are able to spend their entire lives in the ocean. Near shore, they dive to the sea floor for sea urchins, mollusks, crustaceans and some fish.

Sea otters use rocks to knock prey loose and crack shells, making them one of the few tool-using mammals. By eating sea urchins, they protect kelp forests from damage, so they count as a keystone species. Hunting for fur between 1741 and 1911 cut a population of 150,000 to 300,000 down to as few as 1,000 to 2,000. A hunting ban and reintroductions helped them recover.

Did you know?

• Sea otters now occupy about two-thirds of their former range.
• The sea otter's recovery is seen as a major marine conservation success.
• Because sea otters eat seafood people also want, they sometimes clash with fisheries.