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 a quarter of their 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.

Sea Otter

• Sea otters have a flap of fur under each arm they use to store food while foraging.
• 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.

Sea Otter

Care at the Zoo

The sea otter habitat at the Zoo provides deep water to dive, coves, cutouts in the rock structure for animals that may want to be separate from the group, a large surface area for swimming, and ample space for the otters to rest on land. In addition to the public viewing area, the otters have three reserve pools behind the scenes. The salt water in which they swim is maintained at a cool 55–60 degrees F.

Keepers at the Minnesota Zoo strive to provide various forms of enrichment for the sea otters to keep them mentally active and physically healthy. Enrichment includes:

Training - We reinforce desirable behavior with rewards and ignore undesirable behavior. The training builds a positive relationship between the otters and the trainer. It provides positive activities for the otters, gives keepers a way to provide health care without stress, and offers zoo guests an opportunity to learn more about these active and interesting animals.

Toys - help keep the sea otters mentally stimulated as they interact with them by carrying them, diving with them, chewing on them, banging them against rocks as they do their shellfish — even sleeping with them!

Ice - Ice is a favorite treat for sea otters. Keepers provide ice in many different forms. The otters eat it, lie on it, dive with it, or just play with it.

Food - The otters eat shrimp, clam, squid, and fish such as pollock and capelin. Trainers feed the otters during training sessions. The otters also receive a variety of whole shellfish such as clams, mussels, and crabs. They must use their foraging skills and break open the shellfish by banging shellfish together, banging them against rocks, or crunching through the shells with their powerful jaws and large molars. Sometimes keepers place food in toys or freeze it into ice. This is a great way to incorporate two of the otters' favorite things—food and fun!

Meet the Animals

“Capers”

Capers was just two weeks old when he was found as an orphan pup in Kachemak Bay, Alaska, in May 2006. He was taken to the Alaska SeaLife Center in Seward and then transferred to the Shedd Aquarium in Chicago. He came to the Minnesota Zoo in December 2006.

How to Recognize Him:
Capers has light fur around his face and very long whiskers

Distinguishing Characteristics:
Capers loves ice and can often be observed on land eating various ice forms that his trainers have left for enrichment.

“Jasper”

Jasper was found as a lone pup in Kachemak Bay, Alaska, in July 2007. He was initially cared for by the Alaska SeaLife Center. He moved to the Minnesota Zoo in August 2007.

How to Recognize Him:
Jasper is the smallest and darkest of our sea otters.

Distinguishing Characteristics:
Jasper is very playful and curious about the guests that visit his exhibit. He is often seen interacting with people outside his habitat.

“Rocky”

Rocky was found in July 2007 near Craig, Alaska. He too was an orphaned pup cared for at the Alaska SeaLife Center before coming to Minnesota.

How to Recognize Him:
Rocky has a white face, broad head and face. He is the largest of our sea otters.

Distinguishing Characteristics:
Rocky shows the most interest in the enrichment items that his trainers provide for the sea otters. He frequently can be seen interacting with these objects or just carrying them around. Both Jasper and Rocky were transferred to the Minnesota Zoo in August 2007.

 

Things you can do

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Sea Otter

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.

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.

 

Conservation Notes

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.

In 2006, there were thought to be 64,000–77,300 sea otters off the coast of Alaska, Canada, and Washington; about 15,000 in Russia (Kamchatka peninsula and Kuril Islands); and about 2,750 off the coast of California. There are thought to be fewer than 12 Russian sea otters off the coast of Japan.

Sea Otter

Range and Habitat
Sea otters live in shallow coastal waters and in and around the kelp forests of the ocean. They were once found from Mexico to Alaska on the eastern side of the Pacific Ocean and to the coast of Japan in the western Pacific. Today sea otters can be found off the coast of California, Alaska, Canada and Russia. The largest population of sea otters is in Alaska. A small group lives off the coast of Washington and British Columbia, where they were reintroduced in the 1960s.

Description
The sea otter is the smallest marine mammal in the Northern Hemisphere. It is a members of the weasel family, related to mink, fisher, and river otters. The otter has a long, tubular body with a broad head and whiskered snout; blunt, rounded teeth; webbed hind feet; and front paws with short toes used to grab and handle food. The male weighs 70–90 pounds. The much smaller female weighs only 40–60 pounds. Some males can grow to be 6 feet long and weigh up to 100 pounds. The otter’s undercoat is brown or black, and the guard hair may be silver, dark brown, or black. Older sea otters tend to have silvery hair.

Habits and Adaptations
Sea otters live, mate, sleep, groom, hunt, rest, play, and give birth in the ocean. They spend most of their life floating on their backs in the water.

The sea otters are the only marine mammal that does not have blubber to keep it warm. Its fur is critical for keeping them from freezing in the frigid waters of the northern oceans. The fur has two layers, an undercoat and longer outer guard hairs. Otters carefully groom their fur, rolling in the water and rubbing themselves in a way that traps a layer of insulating air bubbles between their warm skin and the ocean water. Their loosely jointed skeleton allows them to groom every inch of their body.

Sea otters can dive 100 feet deep or more when searching for food. They usually dive for 1–2 minutes, but can stay underwater for up to 5 minutes. Sea otters use hearing, smell, touch, and sight to hunt for food and avoid danger. They tuck food items they find into a flap of skin under their forearm. Then they pull them out and eat them after return to the surface. They are able to quench their thirst with seawater because their large, complex kidneys are able to handle the salt.

Eat and Be Eaten
Sea otters eat about a quarter of their body weight each day. They eat a wide variety of invertebrates, including clams, snails, worms, sea stars, sea urchins, crabs, squid, octopuses, and abalone. Alaskan sea otters also eat fish. In the wild, sea otters play an important role in keeping sea urchin populations in balance with the rest of the ecosystem. At the zoo the otters are fed shrimp, squid, clam meat, whole clams, crabs, mussels, krill, pollock, and capelin. Animals that eat sea otters include orcas, sharks, and Stellar sea lions. Bald eagles have been known to prey on sea otter pups.

Life History
Sea otters can mate any time during the year. Males become sexually mature around 4–5 years of age and females mature around 2–5 years of age. Gestation is about 6 months and females usually give birth to a single pup. The female is able to prevent the fertilized egg from developing for several weeks or months. This process, called “delayed implantation,” may allow the pup to be born when food is most abundant.

Baby sea otters pups weigh 3–5 pounds at birth. They have light fur and guard hairs that keep them afloat. The pups are born with a full set of teeth and their eyes open. A sea otter mother carries her pup on her stomach and spends much of her day caring for it. Sea otter pups are dependent on their mother for about one year. A baby otter emits a high-pitched sound when it is distressed or can’t find its mother.

Sea otters segregate by sex. Groups of female and their pups stay in the center of the range. Breeding males stay close to the female groups and younger males are found on the outskirts of the range. Younger males are the first to move into to a new area.

Male sea otters live about 10–15 years and females live about 15–20 years. Sea otters in zoos and aquariums tend to live longer than sea otters in the wild.