Sea otter

Seaotterrocks

Enhydra lutris skull - MUSE

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sea otter with sea urchin

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Sea otter cleaning

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Sea otters holding hands, cropped

Sea otter (Enhydra lutris) is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between 14 and 45 kg (31 and 99 lb), making them the heaviest members of the weasel family, but among the smallest marine mammals. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. Although they can walk on land, sea otters are capable of living exclusively in the ocean.

Description

The sea otter has a small round face, short limbs, and a large, muscular tail. Its fur is a rich brown, often with lighter silver or gold shades on the head and neck. Remarkably adapted for aquatic life, their rear flippers are webbed and large, helping them to steer and dive with ease. Their front paws are smaller, with dexterous fingers used for foraging and eating.

Sea otters are known for their unique behavior of using stones to break open shellfish on their stomachs, a trait which places them in a small group of animals that use tools. They feed mostly on marine invertebrates including sea urchins, various mollusks and crustaceans, and some species of fish.

Habitat and Distribution

Sea otters inhabit shallow coastal waters off the northern Pacific. Their range spans from the Aleutian Islands of Alaska south to California, and as far west as Russia and the northern coast of Japan. They prefer areas with kelp forest canopies, which provide cover from predators and abundant food sources.

Conservation Status

Historically, sea otters were hunted extensively for their fur, leading to a drastic reduction in their numbers. By the early 20th century, they were considered nearly extinct. Conservation efforts, including legal protection and reintroduction programs, have helped their populations to recover in some areas, but they are still classified as an endangered species by the International Union for Conservation of Nature (IUCN). Threats to their survival include oil spills, predation by orcas, and conflicts with fisheries.

Role in Ecosystem

Sea otters play a crucial role in their ecosystem by controlling the population of sea urchins, which can overgraze kelp forests if left unchecked. By maintaining healthy kelp forests, sea otters contribute to the biodiversity and productivity of their habitats. Kelp forests also act as carbon sinks, thus playing a part in climate regulation.

Reproduction and Lifespan

Sea otters are polygynous, and females typically give birth to one pup per year after a gestation period of about six to eight months. Pups are born in the water and are dependent on their mothers for the first six months of their life. Sea otters can live up to 23 years in the wild, although survival rates are significantly lower.

Cultural Significance

Sea otters have been of cultural significance to several indigenous peoples of the North Pacific coast, who hunted them for their pelts and used their bones and teeth for tools and ornaments. Today, they are often considered a charismatic species, playing an important role in the ecotourism industry of their range countries.