FEEDING TYPE: Carnivore
STATISTICS: Weight: 18-24 lbs; Length: 26-42 in. Tail: 12-18 in.
Otters have a long, streamlined body with a broad head, short legs, and webbed toes. The face has a bulbous nose, small eyes, and vibrissae (whiskers near mouth). The small ears and nostrils can be closed when the animal is in water. Otters have sleek, dark brown fur that is short and dense, with a heavy, soft, oily underfur overlain by glossy, smooth guard hairs. The fur underneath is lighter brown than that on top.
Alaska, Canada, and continental United States
Otters can inhabit all types of inland waterways, as well as estuaries and marine coves. They may also be found in burrows, rock, or driftwood piles while seeking shelter, but usually are no farther than 300 feet from the water. Most otters have at least one permanent burrow beside the water.
The otter’s body is designed for a semi-aquatic lifestyle; they swim by moving the hind legs and tail. Eyes and ears are located near the top of the head so it can see and hear while submerged. The ears and nose close automatically when diving and the otter can stay submerged up to eight minutes. It uses anal scent glands to mark territories, which may cover up to 100 miles. Otters are primarily crepuscular (active at dawn and dusk) but may be seen in undisturbed areas during the day.
Dens are constructed under tree roots, thickets and abandoned burrows, usually close to some body of water. Leaves and grasses are gathered to make a nest.
Breeding occurs in winter to early spring. Gestation has been recorded to last from 245 to 380 days. Females use delayed implantation, where the embryo is not implanted into the uterus until the following January, when development of the embryo begins.
Several males will follow a female and fight each other for a chance to breed. Copulation may occur in water or on land. The male is excluded from the family after the young are born for at least six months.
One to four kits are usually born, weighing about eight ounces at birth and with eyes and ears closed. Eyes open at about 35 days, but the kits will not leave the den until about 60 days. At four months the young quit nursing and will separate from the mother at about one year. Otters reach sexual maturity at two years. Males do not seem to be able to successfully obtain a mate until nearly five years of age.
Prey to man and larger mammals
Predator to small aquatic mammals
Once widely hunted for their beautiful and durable fur, otters are now protected in Kansas. Habitat destruction and water pollution are now the biggest threats. The last river otter known to have been collected in Kansas was near Manhattan in 1904.
Otters can still be hunted today in many places, and in recent years, more than 50,000 otters have been taken in North America. Louisiana alone traps more than 10,000 otters per year. Legal otter harvests are supposed to remove animals above what the habitat will generally support.
Pesticides can be harmful to otters. Since otters are on the top of the food chain, many of the animals they eat have chemicals concentrated in their bodies, which can be harmful by the time the otter eats the prey.
- River otters capture their prey with their mouths, not their hands.
- With the possible exception of the Old World badger, river otters are the most playful of the Mustelidae. Some species engage in the year-round activity of sliding down mud and snow banks, and individuals of all ages participate. They are excellent swimmers and divers, swimming at an average speed of seven miles per hour. Unlike muskrats or beavers, the otter barely makes a ripple when swimming or a splash when diving. Otters can also run up to 18 mph and can run and slide, gliding 25 feet on ice.
- Otters can be very vocal. They use chirps, chuckles, grunts, whistles and screams. They use the nose for communication by smelling areas where other otters have marked territories, and although they do not appear to be overly territorial, they do like to let other otters know where their living space is.
- WILDLIFE FACT-FILE, 1996 ed. Group 1: Mammals. "River Otter."
- Novak, Ronald M. Walker’s Mammals of the World. Volume II Baltimore, Maryland. The Johns Hopkins University Press. 1991
- Chanin, Paul. The Natural History of Otters. Kent, Great Britain. Christopher Helm Publications. 1985
Published: September 2009