Sea Otter

by JoAnne Bratten

The sea otter, Enhydra lutris, is a member of the family Mustelidae. Making its home along the Pacific coastline, the sea otter lives primarily in southeast Alaska, California, and some scattered spots along the coasts of British Columbia and Washington. The coastal zone, where the water depth is 100 feet or less, is the sea otter's primary habitat.

Able to dive to 150 feet and remain submerged for up to five minutes, the sea otter is an efficient hunter. It forages primarily in kelp beds, where the fish and invertebrates are plentiful. The strong, flexible plants also make excellent anchor lines while it eats and sleeps, and they provide refuge during storms.

The sea otter consumes 20-25 percent of its body weight in fish and invertebrates daily. Along with hunting, grooming is an essential part of the sea otter's daily routine. Its coat is the thickest among furred animals, with 1,062,000 hairs per square inch. Air trapped in the underfur, which the owner replaces through vigorous drying and blowing, acts as an insulating layer. The coat can only maintain its leakproof barrier if the hairs remain absolutely clean, which explains the sea otter's fastidious nature.

Female sea otters can give birth to one pup annually, but typically average five to six pups in a lifetime. The maternal care provided by sea otters is legendary. A mother will typically carry her pup on her chest for the first few weeks of life, and will supply all of its needs until it is weaned at five to eight months of age, when it begins to live independently.

The sea otter has few predators at sea except the great white shark, which often attacks and kills, but for reasons unknown to biologists, does not eat its sea otter prey. The bald eagle and coyote have also been known to prey on young sea otter pups left briefly alone at sea or on shore. Not surprisingly, humans have been the sea otter's most devastating predator. Before commercial hunting began in the 1800's, there were between 150,000 and 300,000 sea otters living along the pacific coastline. By 1911, when the Fur Seal Agreement was adopted, after 170 years of hunting, only a couple of thousand sea otters remained. Today, the sea otter population has been restored to an estimated 150,000 individuals.