Site hosted by Build your free website today!

North American River Otter

Almost hunted to extinction

Order: Carnivora

Family: Mustelidae

Genus & Species: Lontra canadensis


North American river otters are the largest members of the family Mustelidae. Their body is long and slender with a thick tail that tapers to a point. The feet are fully webbed and are very strong, the five toes ending in sharp claws. The neck is long and the legs are short. The head is flat and the face is whiskered, with small ears and no hair on the diamond-shaped nose. The fully grown are generally 3-4 ft long and weigh 11-23 lbs. They stand 10 inches at the shoulder and the males are larger than the females. The tail is 12-18 inches long.

North American river otters have a thick, velvety fur that is usually black, reddish or grey-brown on the back and light or grey-brown on the belly. The throat and cheeks are yellow-grey. Darker, coarse guard hairs cover the back and make the fur water resistant. North American river otters are well suited for life in the water, with a nose and ears that can close while swimming. The eyes are near the top of the head and have a third clear eyelid called a nictitating membrane that protects the eye underwater. Oily fur and a layer of fat keep their bodies warm in cold waters. The sensitive whiskers and acute sense of smell help them to locate food in the water. Sight and hearing is not as acute.

North American river otters communicate with a wide variety of chirps, chatters and chuckles. When frightened they can emit a loud scream heard 1.5 miles across water. Their mouths contain 36 teeth. They have lived for up to 25 years in captivity and 15 years in the wild. They are extremely playful and will toboggan down icy hills on their bellies.


North American river otters are found in both Canada and America. They are found on the west coast from Alaska south to California and Utah. On the east coast they are found from Newfoundland to Florida. They are found throughout Canada except for the extreme north.

North American river otters are nocturnal but can be seen during the day. They are found in lakes, ponds, marshes, wooded rivers, and streams with backwater areas. They live in dens abandoned by beavers or muskrats and will sometimes kill the occupants of a den to live there.


North American river otters are carnivorous in nature and feed on slow moving fish such as catfish. They also eat crayfish, clams, frogs, reptiles, birds, insects, and small mammals. They catch their prey underwater with their mouths and eat them immediately. They have a rapid metabolism; meals don't last long and they must hunt frequently.


North American river otters are at the top of the food chain and therefore have few predators. However, their thick pelts are valuable and they were almost hunted to extinction in the early 1900's. Conservation efforts have greatly increased their numbers. Today accidental trappings in beaver traps constitute for the most otter fatalities. Mercury, DDT, dieldrin, polychlorinated biphenyls and other toxic chemicals also affect their numbers.

At Yellowstone River coyotes have been known to steal fish that North American river otters have captured.


North American river otters reach sexual maturity at 2 years of age. They mate from March to April in most places. 1-5 young are born 10-12 months later with a gestation period of only 60 days. For the months prior to the 60 days the fertilized egg floats in the uterus, and implants in the uterine wall after 9 months. The female gives birth in a den near the water, and the male is driven away shortly thereafter. The young are 11 inches in length at birth and are helpless for 2 months. They open their eyes after 22-35 days and are weaned at 18 weeks. Females may mate again as soon as 20 days after the young are born.


The North American river otter is one of 13 species of otter found worldwide. There were 19 recognized subspecies, but these have been grouped into only 7.


6. Lontra_canadensis.ftl