Lifespan: 8-21 years
Wild Diet: fish, frogs, invertebrates and small mammals
Zoo Diet: Mainly trout, variety of seafood and bones 1-2 times per week
Predators: Bobcats, coyotes, birds of prey, alligators, and other large predators
IUCN Status: Least Concern
Habitat/Range: Inland waterways, estuaries and marine coves in North America
Characteristics: Built for swimming, river otters have a streamlined body, short legs with webbed feet, dense fur that keeps otters warm, a tapered tail, small ears and nostrils that can close underwater. River otters typically weigh 11-30 lbs. and are 35-51 in. long.
Behavior: Otters are playful animals, exhibiting behaviors such as mud/snow sliding, burrowing through the snow, and water play. Many "play" activities actually serve a purpose. Some are used to strengthen social bonds, to practice hunting techniques and to scent mark. 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. Male and female otters are generally solitary, except when adult females care for their young.
Reproduction: Males and females come together to breed in late winter or early spring. Gestation lasts about 60 days, with births occurring from November to May, but mainly March and April. Females give birth to one to six young per litter in a den near the water. They are born with fur, but are otherwise helpless. They are weaned at about 3 months old. They begin to leave their home range at from 6 months to a year old. Sexual maturity is reached at 2 to 3 years of age.
Conservation: River otters, once distributed throughout major Colorado waterways, were extirpated from the state during the 1900s through a combination of trapping, water pollution and farming activity. In 1906 the last documented sighting was in the Yampa River, in northeastern Garfield County, Colorado. In the 1970's, the Colorado Division of Wildlife (DOW) began restoring populations in their historic range.
River otters rely on the health of our waterways for shelter and food. Though reduced stream flows, habitat destruction and pollution still challenge their recovery, surveys and sightings suggest that river otter populations are surviving.
The Colorado Wildlife Commission down listed river otters from endangered to threatened on the state's protected species list in September 2003, marking the success of the Division of Wildlife's efforts to bring river otters back to Colorado. Many other states have successfully reintroduced river otter back to their local waterways as well, making river otter recovery a success throughout most of North America. Currently, the IUCN considers river otters to be widely distributed and stable throughout their range. Their continued success in the wild will depend on the water qualities and availability of habitat.