A semi-aquatic mustelid that recovered dramatically from near-extinction in the eastern US through reintroduction programs. Playful, social, and a top freshwater predator — and an indicator of clean water.

Also called: River Otter, North American River Otter

Native status: Native; widespread (recovered from past depletion)

§ Quick facts

SizeBody 60–110 cm (24–43 in); tail 30–50 cm
Weight5–14 kg (11–31 lb); males larger
LifespanWild 8–9 years; captive 21
OrderCarnivora
FamilyMustelidae

§ Encyclopedia

The North American river otter, also known as the northern river otter and river otter, is a semiaquatic mammal that is endemic to the North American continent throughout most of Canada and along the coasts of the United States and its inland waterways. An adult North American river otter can weigh between 5 and 14 kilograms (11–31 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur.

Source: Wikipedia — North American river otter Licensed under CC BY-SA 4.0

§ Identification

Field marks. Long sleek dark brown body with paler throat and belly; thick muscular tail tapering to a point; webbed feet; small ears.

Similar species. Sea Otter (lives in marine waters, floats belly-up, much larger). American Mink (much smaller). Beaver (large flat tail).

Voice. Whistles, chirps, growls, hisses; pups whine.

§ Diet & behavior

Diet. Fish (primary), crayfish, frogs, salamanders, aquatic insects, occasional waterfowl and small mammals.

Behavior. Highly social — family groups of mother + offspring; adult males sometimes form bachelor pods. Among the most playful wild mammals — slides down mud or snow banks, juggles stones, plays chase. Extirpated from much of US Midwest by 1900 due to water pollution and trapping; successful reintroductions in 21 states have restored populations across most of historic range.

§ Range

Throughout most of Canada and the continental US

§ Habitat

Rivers, lakes, marshes, coastal estuaries with abundant fish

§ Threats

Pollution and pesticide bioaccumulation, vehicle strikes, fishing-line entanglement.

§ Conservation status

According to the IUCN Red List, the northern river otter is currently classified as Least Concern.

§ What helps

Support clean water rules. Don't leave fishing line in water. Maintain natural shoreline.

Support our work More ways to help

§ Further reading

§ Sources cited

  • River Otter Alliance
  • National Park Service
  • USFWS
  • IUCN Red List 2021