Sea Otter

Overview

The sea otter (Enhydra lutris) is a marine mammal native to the nearshore coastal waters of the northern and eastern North Pacific Ocean. As the smallest marine mammal and the heaviest member of the weasel family, it relies on the densest fur in the animal kingdom for insulation rather than blubber. These animals are considered a keystone species, playing a vital role in maintaining the health of kelp forest ecosystems by controlling populations of sea urchins and other invertebrates.

Distribution & habitat

Sea otters typically inhabit nearshore environments, often in waters less than 54 meters deep. Their range spans the coasts of Russia, Japan, Alaska, British Columbia, Washington, and California, with specific subspecies adapted to these regional waters.

Appearance

Adult sea otters generally weigh between 14 and 45 kg and measure 40 to 65 inches in length, with males typically being larger than females. Their dark brown fur is exceptionally thick, containing up to one million hairs per square inch, which traps air to provide warmth in cold ocean temperatures.

Biology & behavior

Lacking blubber, sea otters must consume 25% to 30% of their body weight daily to maintain their high metabolic rate. They are known for their intelligence and use of tools, such as rocks, to dislodge prey and open shells. While they can walk on land, they are fully capable of living their entire lives in the ocean.

Feeding

They are primarily carnivorous, foraging on the seafloor for marine invertebrates including sea urchins, clams, crabs, mussels, abalone, and sea stars. They often use loose skin under their forearms to store food and tools while diving.

Reproduction

Sea otters are polygynous and can reproduce year-round. Mating is aquatic and often involves aggressive behavior. Females typically give birth to a single pup after a gestation period of approximately six months, which includes a phase of delayed implantation.