North American River Otter

Scientific Name: Lontra canadensis

OtterDescription: These playful mammals are well adapted for semi-aquatic living. They have thick, protective fur to help them keep warm while swimming in cold waters. They have short legs, webbed feet for faster swimming, and a long, narrow body and flattened head for streamlined movement in the water. A long, strong tail helps propels them through the water. They can stay underwater for as much as eight minutes. They have long whiskers which they use to detect prey in dark or cloudy water and clawed feet for grasping onto slippery prey. They are very flexible and can make sharp, sudden turns that help them catch fish. Their fur is dark brown over much of the body, and lighter brown on the belly and face. On land they can run at speeds of up to 15 miles per hour—they can slide even faster. Their playful snow and mud sliding, tail chasing, water play and snow burrowing activities also serve other purposes—they help strengthen social bonds and let young otters practice hunting techniques.

Size: 3-4 feet long including their tail and between 11 to 30 pounds. The tail makes up about 1/3 of their total length. Males are generally larger than females.

Diet: A variety of aquatic wildlife, such as fish, crayfish, crabs, frogs, birds’ eggs, birds and other reptiles such as turtles. They have also been known to eat aquatic plants and to prey on other small mammals, such as muskrats or rabbits. They have a very high metabolism so they need to eat frequently.

Predation: Bobcats, alligators, coyotes, raptors and other large predators will sometimes prey on North American river otters.

Typical Lifespan: They live 8-9 years in the wild but have lived up to 21 years in captivity.

Habitat: They can thrive in any water habitat, such as ponds, marshes, lakes, rivers, estuaries and marshes—in cold, warm or even high elevation areas—as long as the habitat provides adequate food. River otter dens are along the water in abandoned burrows or empty hollows. The dens have entrances underwater so they can be easily accessed from the water.

Range: They occur in much of Canada and the United States, except for portions of the Southwest, and in Mexico in the Rio Grande and Colorado River delta areas.

Life History and Reproduction: River otters breed in late winter or early spring. They generally give birth to between one to three pups. The young are blind and helpless when born. They first learn to swim after about two months. River otters generally live alone or in small social groups.

Communication: River otters communicate with whistles, yelps, growls and screams, as well as touch and body posture. They also scent mark using scent glands near the base of their tails that produce a strong, musky odor.

Fun Fact: Although you won’t see it, northern river otters can close their nostrils to keep water out during long dives.

Conservation Status: North American river otters were hunted and trapped extensively for their fur in the 19th and 20th centuries, and are still hunted in some places. They were extirpated from portions of their range, but conservation and re-introduction efforts are helping populations to recover. However habitat destruction and water pollution still puts these animals at great risk, especially because they are so specialized.

Additional Resources:

Conservation: An Otterly Amazing Comeback, National Wildlife Magazine
Otter Spotter Citizen Science Project--a citizen science project to gather information about river otters in the San Francisco Bay area

Places to View River Otters in the Wild:


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