River Otter Facts - Lontra canadensis - Defenders of Wildlife

The North American River Otter is the only river otter found north of Mexico. Its luscious pelt, which is waterproof and allows the river otter to regulate its temperature, was also a staple of the French fur trade in the 1700-1800s, has drawn hunters for hundreds of years. The color of its fur ranges from grey and white to brown and black.

Diet

River otters primarily eat fish. They are also known to eat whatever is easiest to find, like crustaceans, mollusks, insects, birds, oysters, shellfish, crabs, crayfish, frogs, rodents, turtles and aquatic invertebrates.

Population

The population is unknown because the river otter is one of the hardest mammals to census but is estimated to be over 100,000 based on harvest reports.

Range

River otters can be found in streams, lakes, reservoirs, wetlands and along marine coasts in all states and territories of the U.S. and Canada. River otters are being reintroduced in the Rocky Mountain region to counter the population decrease in the 1800s. See a river otter range map >>

Behavior

River otters live in all types of habitats. The only consistency with these habitats is accessible high quality water and an abundant food supply. A river otter will only settle in a location with sufficient coverage, usually vegetation or physical structures, such as rock piles.

River otters are very playful animals and can often be seen playing games. Social groups are typically made up of adult females and their pups. There are also groups of individual males. River otters are most active at night.

Mating season: December to April.
Gestation: 60-63 days following delayed implantation.
Litter Size: 2-3 pups.

Global Warming and Other Threats

River otters are fish eaters, and fish populations are at risk from global warming due to effects of sea-level rise. If fish populations start to decrease in number or begin moving elsewhere due to climate change, river otters would lose their major food source.

River otters are also threatened by habitat destruction. Historically, they were hunted for their pelts. Today, there is no major threat from commercial harvesting, but local populations can be affected by illegal hunting. The otter’s aquatic habitats are being influenced by human contact. Water is depleted, water quality is lowered, timber and other cover is being cleared, vegetation is becoming scarce and more. Most of the problems are caused by water pollution.

Reasons For Hope

River otters once thrived throughout much of the United States. Trapping caused the decline or extinction of many state populations. Fortunately, 21 states have actively worked to restore or reintroduce otters and they are doing well in most of these areas.

Legal Status/Protection

• CITES: River otters are listed in Appendix II. Appendix II species can be traded commercially only if it does not harm their survival..
• The US Forest Service has declared river otters a Sensitive Species. There are laws protecting river otters in Colorado, Kansas, Nebraska, South Dakota, and Wyoming. Trapping is allowed in some states.

How You Can Help

• Help river otters and other wildlife by adopting a river otter today at our Wildlife Adoption Center.
• Take Action for Wildlife at our Wildlife Action Center.

For additional information

• Visit Defenders' Imperiled Species: River Otter pages for more information about what Defenders is doing to help.
• US Forest Service Report: North American River Otter: A technical conservation assessment
• Alaska Department of Fish and Game River Otter Information
• The Nature Conservancy’s River Otter Page
• IUCN Otter Specialist Group North American River Otter Fact Sheet