The American beaver is the biggest rodent in North America, often weighing more than 55 pounds, and it is Oregon’s state animal, chosen by the Legislature in 1969 for the Beaver State. Prized for its fur, it was trapped out of much of its original range by early settlers, but management and protection have brought it back to waterways across Oregon.
The Oregon Blue Book calls the beaver nature’s engineer. Beavers cut trees for food and for building dams and lodges, and that work shapes how water moves through a stream and helps control erosion. They do best on small streams with a steady flow that wind through fairly flat ground, bordered by trees such as cottonwood, aspen, willow, alder and maple.
Beavers are built for the water, with webbed hind feet, a broad, flat tail, valves that close the ears and nose during a dive, and membranes that cover the eyes underwater. They live in family colonies made up of a mated pair, last year’s young and the newest kits, and pairs usually stay together for years. Beavers do most of their work in the evening and at night and do not hibernate, though in winter much of their activity happens under the ice. On Mt. Hood, look for gnawed stumps, dams and lodges along slow streams and ponds.
How to identify it
A very large, heavy-bodied rodent, dark brown above and lighter below, with a broad, flat, scaly and nearly hairless tail, large webbed hind feet, and small eyes and ears. It swims with its hind feet and tail, holding its front feet tucked under its chin. On land it moves with a clumsy waddle.
Look-alikes
River otters have a long, cylindrical body and a thick tail that tapers toward the tip rather than a flat paddle. Nutria, an invasive rodent in western Oregon, has a round, nearly hairless tail like a rat's and a muzzle frosted with white hairs.
Habitat
Streams, rivers, ponds and wetlands bordered by trees such as cottonwood, aspen, willow, alder and maple, especially small, slow streams with a steady flow through fairly flat ground.
Sightings in the forest
72 research-grade sightings in Mt. Hood National Forest on iNaturalist, most recently on October 23, 2026. See them on iNaturalist →