The Marine otter is the smallest of the otters of the New World otters. This charismatic marine species displays charm and dexterity. It lives along South America’s Pacific coast. It is one of just two species of the family of weasels that spends its time in the ocean, though unlike the sea otter, it does not spend its entire life in the ocean, but lives on land, feeding along the rocky shores, only making short trips into the sea to hunt. Although both these animals live in a marine environment, marine otters are related more closely to the three American river otter species than the sea otter, which indicates that within the weasel family, the coastal/marine lifestyle has evolved twice.
The Marine otter lives along the Pacific Ocean’s coast, from northern Peru to the Isla de Los Estados, Argentina and Cape Horn, Chile. Rarely found in freshwater, this species prefers exposed coastal areas, and tolerates rough conditions and enjoys regions which offer a variety of fish, crustaceans, and mollusks.
When not breeding, these otters mostly live a solitary life. Groups are rarely more than two or three in number. Activity is usually diurnal, with peaks of activity occurring during early mornings, mid-afternoon, and evenings. This species is much more agile in water than on land. They have, however, proved to be wonderful rock climbers. Often these animals float on their back, staying in position with their tail. In this position they can ingest prey even in high waves. These otters often leave the water to go onto the rocky shore where they can feed, sun themselves, groom, and play. Most interactions between these animals are friendly, however, when adults and pairs fight over resources, like captured prey, they may show intense aggression. Such competitions often involve fighting, biting, and high-pitched squeaks, resulting in bleeding wounds.
Marine otters are most likely monogamous, which means that one male mates with one female exclusively. Mating typically takes place during December or January. The gestation period is 60 to 65 days, and births are usually from January to March. Birthing takes place either in a den or on the shore between vegetation and rocky outcroppings. Litters have two to four young, usually two. The young stay with their parents for about ten months. Adults carry their young in their mouths or rest them on their bellies while swimming on their backs. Both adults bring prey to the den for their young to eat. Age at sexual maturity is 3-4 years in females and is probably 7-8 years in males.
This species suffers many threats from different sources. It has been hunted for its pelt over many centuries, used mainly for footwear. Continuing population decline across the range has been the result. More recently, this mammal has suffered habitat loss due to a growing tourism industry, which has meant coastal construction and water sports activities. Water pollution from oil spills and mining of heavy metals, over-fishing of its prey species, drowning in fishing nets and crab traps, and persecution by fishermen, are further threats.
According to the IUCN Red List, the total Marine otter population size is around 800 to 2,000 individuals. Currently this species is classified as Endangered (EN) and its numbers today are decreasing.