Cabrillo Marine Aquarium

Southern Sea Otter

Enhydra lutris nereis


Fun Facts

    Sea otters do not have blubber to keep warm, instead they have very dense fur (up to one million hairs per square inch).

    To maintain its body temperature, the sea otter eats 25% to 35% of its body weight in single day.



  An adult sea otter typically weighs between 30 to 100 lbs, making them the largest members of the weasel family (Family Mustelidea) but the smallest of the marine mammals. A 50 pound otter eats about 11 to 16 pounds of food every 24 hours. In California, the sea otter prefers to eat abalone and red sea urchins because of their high caloric values. As its preferred prey becomes harder to find, the sea otter will eat other food including kelp crabs, clams, turban snails, mussels, scallops, and sea stars.

Unlike whales and seals which rely on thick layers of blubber to keep warm, sea otters depend on its thick fur. The sea otter’s fur is very dense, containing up to one million hairs per square inch. Sea otters must keep their fur clean and therefore spend large amounts of time grooming.

Between 1741 and 1911, sea otters were hunted extensively for their fur resulting in the population declining from150,000–300,000 to 1,000–2,000 individuals. Once common along the entire California coastline, sea otters are now typically only found along central California.

To learn more about sea otters visit the Kelp Forest Room at the Aquarium, download the sea otter fact sheet or stop in at the CMA Library to see our sea otter book collection.