Otter, Marine

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Otter, marine

Lontra (lutra) felina

phylum: Chordata

class: Mammalia

order: Carnivora

family: Mustelidae

status: Endangered, IUCN Endangered, ESA

range: Argentina, Chile, Peru

Description and biology

Otters are members of the weasel family. The marine otter, sometimes called the sea cat, has a long body, a flat head, small ears, and a broad, whiskered muzzle. Its short legs and webbed feet help make it an agile swimmer. Thick, glossy dark brown hair covers its body. An average marine otter has a head and body length of 22 to 31 inches (59 to 79 centimeters) and a tail length of 12 to 14 inches (30 to 36 inches). It weighs 7 to 31 pounds (3 to 14 kilograms).

Marine otters feed mainly on crustaceans (such as crabs and shrimp) and mollusk (such as snails, clams, and oysters). While swimming on their backs, they often lay their prey on their chests and use rocks to smash open the hard shells. The otter's main predator is the orca (killer whale).

The otters are primarily solitary animals, but groups of three or more have been observed in the wild. Male and female marine otters mate at any time during the year, although primarily during the summer. After a gestation (pregnancy) period that lasts between 60 and 120 days, female marine otters usually give birth to a litter of two pups.

Habitat and current distribution

The marine otter ranges along the Pacific coastline of Peru and Chile south to the Strait of Magellan, a narrow channel separating South America from Tierra del Fuego and other islands south of the continent. The otters are found primarily in the southern region of their range. One scientific study estimated that the total marine otter population numbers less than 1,000.

Marine otters prefer to inhabit exposed rocky coastal areas and secluded bays and inlets near estuaries (regions where a river empties into an ocean). While searching for freshwater shrimp, marine otters have been known to swim 2,000 feet (610 meters) up a river from the ocean.

History and conservation measures

Marine otters were once plentiful throughout their entire range. However, because the animals have been long hunted for their fur, they are now endangered or on the verge of extinction in many areas. Water pollution also may be responsible for the destruction of sections of their habitat.

International treaties have banned the sale of marine otter pelts, but no other current conservation measures are underway.


The preservation of otters is important for all species, including humans. Otters are found on all continents except Australia, live both in water and on land, and are near the top of the food chain. For this reason, they are an important indicator species (plants or animals that, by their presence or chemical composition, give some distinctive indication of the health or quality of the environment). A drop in the number of otters could indicate that the areas they inhabit (watermeadows, rivers, estuaries, lakes, coastal zones) or the food they eat (fish, crustaceans, mollusks, frogs) may be in poor condition.

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Otter, Marine

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