A river otter is built for the water: a long, muscular body, short legs with fully webbed feet, a thick tail that tapers from a wide base, and dense underfur covered by stiff, glossy guard hairs. Its broad, blunt head carries small ears, long whiskers and nostrils that close underwater, and it can stay submerged for several minutes at a time.
Otters eat mostly aquatic animals, especially slow fish such as suckers, along with frogs, crayfish and other invertebrates, and now and then birds or small mammals. Their whiskers help them find prey in murky water. They usually hunt at night but can turn up at any hour, and they travel overland between rivers, lakes and ponds. A single otter’s range can stretch for miles along a waterway.
River otters are more social than most members of the weasel family. Mothers stay with their young for months, and otters of various ages are sometimes seen traveling together. They are famous for play, sliding down mud and snowbanks and tumbling in the water, behavior that also helps build bonds and practice hunting. Dens are usually in burrows dug by other animals, under logs or in banks, with an entrance below the water.
Otters disappear from polluted water, so seeing one is a good sign. Look for them on rivers, streams and quiet lakes around the mountain, especially on the west side of the Cascades.
How to identify it
Long, streamlined body about 3 to 4 feet long including a thick, tapering tail, weighing about 11 to 30 pounds. Brown to nearly black above, lighter below, with a paler throat. Small ears, a blunt, flattened head, long whiskers, short legs and webbed feet.
Look-alikes
American mink use the same waters and have a similar dark coat, but a mink is much smaller, with a pointed nose and a bushy tail about half the length of its head and body. An otter has a blunt head and a thick tail that tapers to a point.
Habitat
Rivers, streams, lakes, ponds and marshes with a steady food supply and easy access to the water. In Oregon they are found mostly west of the Cascades, with scattered records farther east.
Sightings in the forest
25 research-grade sightings in Mt. Hood National Forest on iNaturalist, most recently on September 28, 2026. See them on iNaturalist →