North American River Otters


In the Zoo

Scientific Information

Scientific Name: Lontra canadensis
Class: Mammalia
Order: Carnivora
Family: mustelidae
Genus: Lontra




Length: 2.9- 4.25 feet 2.9- 4.25 feet
Weight: 11-30 pounds 11-30 pounds
Maturity: 2-3 years 2-3 years

Lifestyle and Lifespan

Diet: Carnivorous
Activity Timeframe: Cathemeral
Interactivity: Solitary
Sexual Dimorphism: Yes
Gestation: 2 months
Lifespan in the Wild: 8-9 years
Lifespan in Captivity: 21 years

Geographic Range



Status in the Wild:
Threats: Pollution


North American River Otters have long, slender, and sleek bodies. Head is small and round, with small eyes and ears; prominent whiskers. Legs short, but powerful; all four feet webbed. Tail long and slightly tapered toward the tip with musk-producing glands underneath. The short dense fur is dark brown. Chin and stomach are reddish yellow, tinged with gray. Females are usually a third smaller than males.

Species Specifics

Unlike sea otters, river otters are smaller, swim on their bellies, sleep in underground dens, and eat their food on a log or rock, not on their bellies.

Physical Characteristics

American River Otters are almost impervious to cold because of an outer coat of coarse guard hairs, plus a dense, thick undercoat that helps to "water-proof" the animal. They have no blubber; it's the fur that keeps them warm. Perianal scent glands are used for identification, defense, marking territory, and trail marking. Small ears and nostrils can be tightly closed when in water; they are excellent swimmers and divers. During a dive, their pulse slows to a tenth of the normal rate of 170 beats a minute, thereby conserving oxygen







Ecological Web

North American River Otters are important predators of fish and aquatic invertebrates.

Activity and Behavior

Activity Pattern


Social Behavior

American River Otters live alone or in family groups, typically females and their young. They are known as playful animals, exhibiting behaviors such as mud or snow sliding, burrowing through the snow, and waterplay. Many "play" activities actually serve a purpose. Some are used to strengthen social bonds, to practice hunting techniques, and to scent mark. North American river otters get their boundless energy from their very high metabolism, which also requires them to eat a great deal during the day.They are excellent swimmers and divers, able to stay underwater for up to 8 minutes. They are also fast on land, capable of running at up to 29 km/hr. These otters normally hunt at night, but can be seen at all times of day. North American River Otters communicate using a variety of techniques. They vocalize with whistles, growls, chucles, and screams. They also use paired scent glands near the base of their tails for scent marking. They also urinate or defecate on vegetation within their home range to mark territory. They also use touch and posture as a means of communication.

Reproductive Behavior

The female mates in the spring shortly after giving birth to two to four young (or she might skip a year). The new litter of young will not begin to develop until late in the fall. This process, known as delayed implantation, enables the fertilized eggs to mark time within her, receiving only sparse ration to stay alive for several months. Then, within her body, a signal awakens the tiny embryos which resume their growth. The otter pups start their life in a burrow in a river bank, usually an abandoned muskrat den. Born blind and helpless, they are nursed by the female for a month. Venturing out of the den, they rough-house and play in the shallow water, where their mother teaches them to swim and hunt.


2-4 offspring, open eyes at 1 month, weaned at 3 months, independent at 6-12 months





Originally this species is thought to have ranged from 250-700°N latitude and from 530 to 1660°W longitude. Habitat loss and pollution caused reductions in range area and the species is now absent or rare in Arizona, Hawaii, Indiana, Iowa, Kansas, Kentucky, Nebraska, New Mexico, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, and West Virginia. Reintroductions have expanded the distribution of this species in recent years, especially in the Midwestern United States.

Current Threats


Our Role

How You Can Help

Fascinating Facts


Otter droppings are called spraints.


Serfass, T., Evans, S.S. & Polechla, P. 2015. Lontra canadensis. The IUCN Red List of Threatened Species 2015: e.T12302A21936349. Downloaded on 03 October 2016.

Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2016. The Animal Diversity Web (online). Accessed at

"North American River Otter - Brandywine Zoo - Wilmington, Delaware 302.571.7747." North American River Otter - Brandywine Zoo - Wilmington, Delaware 302.571.7747. Delaware Zoological Society, n.d. Web. 17 Oct. 2016.

"River Otters Versus Sea Otters: What's the Difference ..." Otters Up Close. Aquarium of the Bay, n.d. Web. 24 Oct. 2016.

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