North American River Otter

About North American River Otters

The North American river otter is a member of the weasel family. It is very well adapted to life in water. Otters have short powerful legs, webbed feet, a streamlined body that is about 2.5 feet long and a tail that is flattened and well-muscled. This tail is important for swimming and makes up about half of the otter's body length.

On average otters weigh about 20 pounds. The dorsal side of the otter's fur is dark brown and the ventral side is light yellow. This is a color adaptation that is known as counter-shading. If a predator is above the otter, when it looks down, the otter blends in with the dark bottom. If a predator is below the otter, when it looks up, the otter blends in with the bright light from above.
Otters also have coarse guard hairs and a thicker undercoat, which helps to waterproof them and keep them warm.

Otters are well known for their playful behavior, especially when they are young. The playfulness of young otters helps them to strengthen social bonds and to practice hunting techniques.

River otters are usually found alone or in pairs but can communicate with others in various ways. They vocalize with whistles, growls, chuckles, and screams. They also communicate through scent markings using their paired scent glands near the base of their tail. These glands produce a strong, musky odor. Otters can also mark by urinating or defecating on vegetation.

Otters prefer the aquatic habitat, but they will also roam on land. When alarmed, however, they make a mad dash for the water. When in water, the otter's nostrils and ears can be closed. They can stay underwater for 6-8 minutes before they need to surface for another breath of air. Otters are usually nocturnal, but they may also be active at both dusk and dawn. They obtain most of their food from their aquatic environment. An otter will use their long whiskers to feel for prey in the aquatic substrate. Prey is captured in the mouth and eaten right away. River otters occupy a top trophic level in the food web and will eat anything that is plentiful in their environment. However, while they have few predators they are still sometimes hunted by alligators, bobcats, and birds of prey.

North American River Otter at the Akron Zoo

Our otters can be found in the Mike & Mary Stark Grizzly Ridge area. This habitat includes a fully enclosed slide for guests that goes through the otter pool.

Molly – female, born February 26, 2012
Stratton – male, rescued, estimated birthdate March 15, 2013

Classification

Order: Carnivora
Family: Mustelidae
Genus: Lontra
Species: canadensis

Fun Fact

Otters are well known for their playful behavior, which includes playing with other otters, mud and snow sliding and burrowing through the snow. Such actions are found most often in young otters and in animals in human care. This is likely because adult otters in their native habitat need to conserve energy for hunting.

Habitat

Otters are usually found no more than a few hundred meters from the water. Most species are entirely dependent on aquatic habitats for food. Otters inhabit rivers, streams, lakes, ponds, and various marshes.

Geographic Range

The North American river otter can be found throughout the United States and Canada.

Diet

River otters primarily eat fish. However, they are opportunistic and will also eat snakes, worms, birds, eggs, small mammals and frogs. Otters capture prey in their mouths and consume it right away.

Population Status

Currently, they are listed as a species of “least concern” on the IUCN Red List after a successful reintroduction effort in 1986.

Field Conservation

The history of otters is both a tragedy and a success. Throughout the mid-1800s, otter numbers began to decline due to unregulated hunting and trapping. Many Europeans hunted otters for their dense fur. The otters’ aquatic habitat was also degraded by pollution, dumping and runoff. By the early 1900s, river otters could no longer be found in any Ohio waterways.

In 1986, waterways were deemed clean enough to support otters, and the Ohio Division of Wildlife began a project to reintroduce the species back into the state. Over a seven-year period, 123 otters were released throughout the state and began making a successful comeback. In March 2002, the river otter was removed from the endangered species list and downgraded to a threatened species. Today, the North American river otter is listed as “least concern” on the IUCN Red List. In 2012, it was estimated that there are over 8,000 river otters in Ohio.

Protection of the otters' habitat not only benefits otters but all of the marine organisms in the area. Many people do not know that freshwater mussels, crayfish, amphibians, and freshwater fish are among the top four endangered groups of animals in the United States. Many people are not as passionate about saving these groups of animals as they are about saving otters, but when the otters' habitat is protected, these groups of animals also benefit.

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North American RiverOtter