North American river otters are rare throughout most of their former range. They are still found in Alaska and most of Canada, in the Pacific Northwest, the Great Lakes states and along the Atlantic Coast and Gulf of Mexico. Now that rivers and streams have been cleaned up, several states, including Colorado, are reintroducing otters to their former habitat.
River otters live in estuaries, fresh water lakes, streams, rivers and coastal areas. As long as there is unpolluted water and an adequate supply of food nearby, they can be found in prairie, tundra and high mountain ecosystems.
- River otters are three to four feet (0.9-1.2 m) long from nose to tail.
- Weight is 15-30 pounds (7-14 kg); males are larger than females.
- Dense short brown fur with silver or grayish fur on their bellies, throat and cheeks.
- They have long streamlined bodies, thick tapered tails and short legs.
- Their feet have claws and are completely webbed.
What Does It Eat?
In the wild: Fish, crayfish, eels, turtles, snails, water insects, amphibians, birds, eggs, small mammals and occasionally aquatic plants.
At the zoo: Commercially prepared meat, fish and dog chow. They get live prey for behavioral enrichment.
What Eats It?
Otters are sometimes subject to predation by bobcats, wolves, coyotes, birds of prey, alligators and other large predators.
Otters are solitary except for mating pairs and females with young. They are slightly territorial and practice mutual avoidance rather than fighting over territory.
Otters are mature at about two years. Mating occurs in late winter or early spring. Although gestation only lasts two months, the young may be born up to a year after mating since otters exhibit delayed implantation. Litters of one to six kits are usually born in the spring when the weather is warmer and food is plentiful. The young are born blind and helpless but fully furred with short whiskers and developed claws. They weigh about four ounces (112 gm) at birth and are about the size of a chipmunk. Their eyes open at about one month and they are weaned at about three months. The young begin venturing out of the den at about three months, when they start learning how to swim and how to catch prey from their mother. By six months they are full grown and proficient at hunting and swimming. They may stay with their mother until they are eight to 12 months old or until a new litter arrives. River otters live up to 15 years in the wild and up to 25 years in captivity.