In the wild, up to 16 years; up to 23 years in captivity

Sexual maturity is reached at 2-3 years of age.

In the wild, they eat mainly aquatic organisms such as amphibians, fish, crayfish, and other invertebrates.  Birds and small terrestrial mammals are eaten on occasion.  In the Zoo, they are fed carnivore diet, dog chow, rats and fish.

River otters are usually found alone or in pairs, but they often socialize in larger groups.  This species is often referred to as "playful" and "enjoying life to the fullest."  Behavior such as mud/snow sliding, burrowing and constant play activity with other otters is commonplace.  Many "play" activities actually serve a purpose.  Some are used to strengthen social bonds, to practice hunting techniques, and to scent mark.  River otters get their boundless energy from their very high metabolism, which also requires them to eat a great deal during the day.

River otters have very large home ranges and are constantly on the move within this range.  Despite the sizable area, river otters are territorial but generally practice mutual avoidance.  In their travels on land, river otters cover as much as 55 miles each year.

They can be either diurnal or nocturnal, but are generally more active at night.

River otters communicate through a wide range of activities. They vocalize with whistles, growls, chuckles, and screams. They also scent mark using paired scent glands near the base of their tails or by urinating/defecating on vegetation within their home range. These glands produce a very strong, musky odor.

Males and females come together to breed in March-April.  One to five young are born after a gestation period of 8 to 12 months following delayed implantation of the fertilized egg in the uterus.  The female makes her holt, or den, in an abandoned beaver lodge or a burrow on the band of a stream or lake where she gives birth.  The male is driven away from the den shortly after the birth of the kits, or young, but is later allowed back to help care for them.  Young are quite helpless for about 2 months.  Weaned after 3-4 months, they remain with their parents until sometime after their first year.

Prey is captured with the mouth after a short chase underwater.  Aquatic animals like minnows, trout, catfish, sculpins, and perch are taken this way.  In addition, otters will eat frogs, insects, and small mammals like shrews, muskrats, and young beavers.  An ingenious predator, otters sometime break holes in beaver dams, waiting for the water to run out before feeding on all the fish frogs now stranded.

Many adaptations for an aquatic lifestyle - small rounded head with ears and nostrils that can be sealed to keep out water; long, slender body with a tapered tail; four webbed feet for swimming and claws for digging.  The otter's long whiskers are used to detect organisms in the substrate. Their fur has 2 layers - outer guard hairs and a dense layer of underfur that keeps water from soaking through to the skin.  They have powerful jaws and sharp teeth.  Their eyes are especially adapted for seeing well above and below the water.

Otters can remain underwater for 6-8 minutes.  They have been reported reaching swimming speeds of approximately 7 mph.  Maximum dives of up to 60 feet have also been observed.

The name “otter” is known to be from the Sanskrit udra or udan, which means, “water.”  Pliny the Elder named the otter Enhydris, meaning, “having to do with water.”

The otter is the only other mammal, apart from primates, that has learned how to use a tool.  Otters use stones to break open mussels, clams and other shell-enclosed prey.

On land, the river otter has been clocked at speeds of up to 18 mph.

To the Pawnee Indians the supreme animal power is the otter.  Symbolic of wisdom, the otter is believed to be the wisest of all animals.  The Winnebago Indians also believed in the wisdom of the otter, and their medicine men relied upon its guidance.  Pouches made from otter skin were used by the medicine men to hold their medicines and charms.  Some tribes believed that the otter symbolized feminine energy and the power of water.

In true “Bre’r Rabbit and the Tar Baby” style, stories are told of how Otter would be caught and would beg not to be thrown into the water.  His pursuers would laugh and do just that, and then Otter would laugh last as he swam away gracefully.  It was believed that Otter helped dead souls across the lake to the spirit world.

It was once believed that if an otter possessed you, or if you ate otter meat or even a fish killed by an otter, you would lose your memory.  If this happened, a tight band was sometimes tied around the person’s head to keep the otter from coming into the brain.

A dried otter heart was thought to be a cure for cholera.

As a group, otters have suffered greatly due to habitat destruction, the use of pesticides, and excessive trapping.  The river otter is becoming increasingly rare in the United States and Canada.  At one time considered to be on the brink of extinction due to trapping and pollution, they have made a comeback due to state wildlife department protection efforts.