Temperate to sub-polar latitudes in the north Pacific Ocean
Rocky shores and kelp forests
Order Carnivora (carnivorans), Family Mustelidae (weasels and relatives)
The charismatic sea otter is one of the most well-known marine mammals today. The largest member of the weasel family, they can grow to be nearly 5 feet long and weigh almost 100 pounds. They spend nearly their entire life in the ocean in the temperate coastal waters on the Pacific Coast and have a close relationship with kelp forest habitats along the North American coast.
Sea otters feed almost exclusively on marine invertebrates such as sea urchins, clams, mussels, and crabs. Since shelled prey like this can be difficult to eat, sea otters have devised a special way to break open their meal. Otters will dive down to collect a rock which they then strike their prey with repeatedly until it opens. Their special taste for sea urchins means that sea otters serve an important ecosystem role in regulating sea urchin populations and preventing overgrazing on giant kelp. This in turn helps kelp forests flourish, making sea otters a “keystone species” in the ecosystems where they live.
Male sea otters reach sexual maturity at around five to six years old, while females mature at around four to five and typically give birth to a single pup every one to two years. Pups depend on their mother for about six months. As they grow, they develop an extremely thick fur coat- the densest of all animals. Since sea otters lack the thick layer of blubber that most marine mammals have to insulate them from cold ocean waters, sea otters depend on their thick fur to keep them warm. Unfortunately, this unique adaptation also made otter fur very attractive, almost driving the species to near extinction through the 18th and 19th century fur trade. Though sea otters have gained legal protection throughout much of their range, today oil spills pose the greatest human-made threats to these creatures, as oil causes a sea otter’s fur to lose its insulation ability, leading to hypothermia. This threat, combined with effects of climate change and habitat loss, contributes to the sea otter’s endangered status.
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