North American River Otter

North American River Otter

[ Lutra canadensis ]

Quick Facts

BODY LENGTH: 3 to 4 feet (with tail)
WEIGHT: 6 to 30 pounds
WILD DIET: fish, frogs, crayfish, aquatic insects, clams, and turtles
ZOO DIET: carnivore diet, dog food, fish, crayfish, fruits and vegetables, eggs, clams
DISTRIBUTION: Alaska, most of Canada, and parts of the continental United States south to Florida
HABITAT: rivers, wetlands along rivers, streams, swamps, ponds, and lakes


In the Water and On the Land

The play’s the thing
There’s nothing like otters at play--they slide down riverbanks, slink under logs, and swim through streams. Whether they play alone or with other otters, otters play with a purpose. In young otters, play develops hunting skills. And for otters of all ages, playing strengthens family ties--the family that plays together, stays together!

The wetter the better
Otters stick close to streams, rivers, ponds, lakes, and wetlands. Otters are well adapted to water. Their body is long and streamlined, ending in a strong tail used to propel themselves in the water. They have webbed back feet that help with steering. With their flexible spines, otters can make sharp, sudden turns around any obstacle in the water. They use their aquatic skills to catch swimming fish, their main prey.

Land ho!
But otters are versatile animals, and they spend quite a bit of time on land, usually along the shore or moving between bodies of water. Even though they are so comfortable in the water, getting around on land is no problem for otters. They often use a combination running and sliding style on land. On mud or snow they can slide 18 miles per hour! Otters scent mark the ground, rocks, and trees near their water homes to keep out intruders.

How’s the water? Ask an otter
If you see a river otter in the wild, you know the water nearby must be pretty clean. River otters are a good measure of water cleanliness. One of the reasons there are fewer of them around nowadays is that water quality in North America got steadily worse for most of the last century. Otters are top predators, which means they are at the top of the food chain. They eat small animals that eat really small animals that eat plants, and so on.

If there are any toxic chemicals in the water, these pollutants make their way up the food chain to the otters, increasing in concentration as they go. There, the chemicals stay in the otters’ fat layer, sometimes for years. That makes otters unhealthy and unable to reproduce enough young to keep the population going.

Otters in Illinois
And that includes populations in Illinois, too. At one time otters were a common sight in Illinois, but they all but disappeared as the state’s water quality declined. A decade or more ago, you could still see otters along the Mississippi River once in awhile, and also in southern Illinois. But sightings were rare. But in recent years water quality improved in Illinois, and scientists decided that otters may be able to live in Illinois again. Between 1994 and 1997, a total 346 otters were reintroduced to some of Illinois’ wild places.

Success with a capital "S"
The reintroduction of river otters to Illinois has been a real success. The original 346 otters reintroduced to Illinois in the mid 90s, along with the few that were already here, have increased to the population by thousands! That might seem like a lot of otters, but it’s a far cry from the number that swam Illinois’ waterways in the past. With clean water and laws to protect the otters, populations should continue to grow.

North American river otters at Brookfield Zoo
You can see river otters in The Swamp, an exhibit that explores the benefits of wetlands to people and animals.

Get Involved

Conservation Fund of the Chicago Zoological Society