Home
Donate Sign up for e-network
CENTER for BIOLOGICAL DIVERSITY Because life is good
ABOUT ACTION PROGRAMS SPECIES NEWSROOM PUBLICATIONS SUPPORT

Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

NATURAL HISTORY

SEA OTTER } Enhydra lutris
FAMILY: Mustelidae


DESCRIPTION: Sea otters use their rear flippers to move and their flat, muscular tails to steer. They have an exceptional sense of smell, hearing, and eyesight above water and below. Lacking blubber, otters have amazingly thick fur to assist in retaining heat. Males weigh 65 pounds on average and are around four feet in length; females are slightly smaller.

HABITAT: Sea otters inhabit coastal waters, usually less than half a mile from shore. Their typical haunts include precipitous rocky shores, barrier reefs, tidewater stones, and dense kelp forests.

RANGE: Sea otters can be found in California, Washington, Canada, Alaska, Russia, and Japan. At one time, otter populations inhabited a contiguous range from Japan around the Pacific coastline down to Baja California.

MIGRATION: Sea otters do not migrate long distances. Local migration may occur.

BREEDING: Female otters reach sexual maturity at three years of age, and males follow at five to six years. Delayed implantation produces varied gestation times, most often between six and seven months. On occasion, twins are born, yet because females provide all of the parental care and the mother otter can’t care for both twins, one is abandoned. Weighing up to five pounds, pups are born in the water with their eyes open. They start eating solid foods shortly after birth, but are dependent on their mothers for up to a year. Pups start diving within two months.

LIFE CYCLE: Male sea otters live between 10 and 15 years, while females live slightly longer, from 15 to 20 years.

FEEDING: Underneath each of the sea otter’s powerful front paws is a pouch to store food collected during foraging dives. Otters carry large stones between their forepaws on these dives, used to dislodge prey and to break open shells. Their diet includes clams, crabs, sea urchins, starfish, abalone, and 40 different marine invertebrates. They also eat octopuses, squid, and fish. Sea otters have a high metabolism rate and eat 25 percent of their body weight every day — an adult will consume 5,000 to 6,000 pounds of food annually. Otters eat while floating on their backs, using their chests as dining tables.

THREATS: Wastes containing heavy metals, pesticides, and PCBs continually pour into coastal waters, threatening sea otter populations. Oil spills are a huge threat to the species because the petroleum coats the fur that is so vital for keeping otters warm. Fishing nets, which otters become caught in, are another major cause of death.

POPULATION TREND: Sea otters once numbered several hundred thousand, yet their populations plummeted due to the surging fur trade of the 18th and 19th centuries. Southern sea otters rebounded until the 1970s, when populations again began to dwindle. The northern population in southwest Alaska has shrunk by 95 percent in the last 30 years, with only 6,000 individuals remaining.

Photo © Don Getty