The marine otter is a charismatic marine mammal that lives along the Pacific coast of South America. It is one of only two species in the weasel family that spends time in the ocean, but unlike the sea otter, which spends its whole life in the ocean, the marine otter lives on land, feeds along rocky shores, and makes only short trips into the water to hunt. Though they both live in the marine environment, marine otters are more closely related to the three species of American river otters than to the sea otter, indicating that the coastal/marine lifestyle evolved twice in the weasel family.
Marine otters are foraging predators that eat a wide variety of prey. While they prefer invertebrates, including crabs, clams, and other hard-shelled groups, they are also known to eat some fishes, juvenile birds, and even other mammals. They also scavenge for garbage, bringing them into close contact with people. Unlike many species of weasels, scientists believe the marine otter to be monogamous. Mating, birth, and nursing take place onshore, in protected dens. Adult marine otteres are quite small. They only reach about 13 pounds (6 kg) vs. 100 pounds (45 kg) in sea otters.
Unlike most marine mammals that rely on a thick layer of blubber to insulate them from cold ocean waters, marine otters rely on their extremely thick fur. Unfortunately, their fur also nearly led to this species’ demise. Excessive hunting reduced the numbers of marine otters significantly and now the species is endangered (highly vulnerable to extinction). The geographic range is also constricted compared to pre-hunting times, and it may still disappear from some places, as poaching continues to be a problem. Though the marine otter has complete or partial legal protection throughout its range, it continues to show decreasing populations. Without continuing conservation measures and legal protection, this charismatic species could be at risk of being lost forever.