Sea Otter

Enhydra lutris

Playful sea otters thrive in the frigid waters of the Pacific Ocean among some of the world’s richest fisheries. Their habitat includes kelp forests, beds of salt-water algae that provide rich habitat for other living things. Sea otters survive the cold and wet with dense fur and active lives fueled by large amounts of seafood. They are critical links that help to keep the ecosystem in balance.

What They Eat

Sea otters eat 25 to 30 percent of their body weight each day in seafood, including sea urchins, fish, clams, snails, worms, sea stars, crabs, squid, octopus, and abalone.

Where They Live

These marine mammals thrive in cold coastal waters and kelp forests from Russia’s Pacific Coast to Alaska and down to California. Sea otters may venture onto land but function best at sea.

What They Do

Sea otters move almost constantly and eat a lot. Watch for them to dive for food, use tools to open shells, clean their fur, and play.

How They’re Doing

Down to fewer than 2,000 by 1911 due to overhunting, sea otters are recovering in some—but not all—areas. Along Russia’s Pacific coast, populations are threatened by uncontrolled development. California and parts of Alaska have seen declines in recent years for reasons that are unclear. Orcas may have an influence on the decrease in the Alaskan population as the whale’s prey items decline.

seaOtter_webRangeMaps

Where in the World
Asia
North America
Habitat

Ocean

Conservation Status

conservationStatus_EN

Animal Facts

Weight: females 40–60 pounds, males 70–90 pounds
Length: 4½ feet

Taxonomic Category

Mammal, carnivore

Where at the Zoo

Russia's Grizzly Coast

  • Sea otters have a fold of skin under each arm they use to store food while foraging.
  • Sea otters have the thickest fur of any animal. They have 10 times as many hairs in one square inch as you have on your entire head! Their fur helps them stay warm in chilly water.
  • Sea otters are the only marine mammal that lack blubber for insulation.
  • Sea otters can stay under water for up to five minutes.
  • Sea otters are tool users. They set rocks on their chests and smash shellfish against them so they can get at the meal inside.
  • The sea otter’s fur is the thickest fur of any mammal, with 850,000–1,000,000 hairs per square inch.
Some 150,000–300,000 sea otters once ranged along 6,000 miles of northern Pacific coastline. Then, a century ago, hunting for furs drove sea otter numbers down to fewer than 2,000 worldwide. Thanks to a 1911 international treaty banning hunting, there are now about 100,000 in the wild. Still, sea otters are threatened by oil spills, habitat loss, food limitations, entrapment in fishing gear, and conflicts with the shell fishing industry. The historic population of sea otters was thought to be between 150,000–300,000 worldwide. In the 1700s, large-scale hunting for fur began to affect that number. By the early 1900s, the population worldwide had dropped to an estimated 1,000–2,000 due to fur trade. In 1911 sea otters were given protection under international treaty. In the early 1900s, people thought the southern sea otter was extinct. Then, in 1915, scientists discovered a group of 50 or so living in a remote cove in Big Sur, California. They kept it a secret until 1938 to protect them. The building of Highway 1 along the California coast made it impossible to keep the secret anymore. All of the California sea otters swimming in the ocean today are descended from the Big Sur group. Today sea otters are listed as threatened under the Endangered Species Act of 1972. They are listed as endangered by the IUCN. Threats include oil spills, habitat loss, food limitations, fishing gear entrapment, and conflicts with fisheries. Oil spills from ships have killed thousands of sea otters. The oil damages the sea otters’ fur and causes the otter to get cold and wet. When an otter attempts to groom its fur it ingests the oil, which can cause liver, kidney, and lung damage. The global population of sea otters was estimated at 106,822 in 2007. Of those, roughly 73,00 live near Alaska, and California is home to over 3,000. 
Things the Zoo's done/doing
The Minnesota Zoo has helped researchers study why some sea otter populations are falling. Understanding the cause is the first step to a solution.