Types of Beavers in Oregon
Oregon is home to one species of beaver, the American Beaver, a large, semi-aquatic rodent found throughout the state in rivers, streams, ponds, and wetlands. These are the only beavers you will encounter in Oregon, whether you are looking along the Columbia River Gorge, the Cascade foothills, or coastal areas. The American Beaver is widespread and common enough to spot year-round, though activity peaks from March through May when water levels rise and they rebuild dams after winter.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself.
- 1
- species recorded
- April, May, March
- peak months
Real sighting data, source iNaturalist
2,592 verified observations on iNaturalist of beaver have been recorded in Oregon, most often in April, May, March.
When beaver are recorded in Oregon
Oregon is home to one species of beaver, the American Beaver, a large, semi-aquatic rodent found throughout the state in rivers, streams, ponds, and wetlands. These are the only beavers you will encounter in Oregon, whether you are looking along the Columbia River Gorge, the Cascade foothills, or coastal areas. The American Beaver is widespread and common enough to spot year-round, though activity peaks from March through May when water levels rise and they rebuild dams after winter.
Is there more than one species of beaver in Oregon?
No. The American Beaver is the only beaver species in Oregon and throughout the Pacific Northwest. This single species is found in suitable freshwater habitats across the entire state. You will never encounter a different beaver species in Oregon waters.
How to identify an American Beaver
American Beavers are large rodents, weighing 35 to 66 pounds on average, with stocky builds and dense, reddish-brown to dark brown fur. Their most distinctive features are their flat, scaly tail (used for swimming and fat storage), small rounded ears, and large orange front teeth visible even at a distance. Adults are much larger than muskrats or otters, which might otherwise be confused with beavers in water. Their hind feet are webbed, and their front feet have sharp claws for cutting wood.
What size are beavers in Oregon?
American Beavers in Oregon average 35 to 66 pounds, with females typically smaller than males. Full-grown adults can reach 3 to 4 feet in body length, not counting the tail. Their tail adds another 10 to 20 inches. These measurements make them the largest living rodent in North America and easily the largest rodent in Oregon.
Color and fur of Oregon beavers
American Beavers display reddish-brown to dark brown fur year-round. Some individuals appear nearly black, while younger beavers or those recently emerged from burrows may appear lighter. The color variation is natural and not a sign of a different species or subspecies. All American Beavers share the same dense, waterproof coat that insulates them in cold water.
What are beaver teeth like?
Both upper and lower front teeth are large, prominent orange incisors that continue growing throughout life. These teeth are self-sharpening and capable of felling trees ranging from saplings to 6 inches in diameter. The teeth are visible from a distance, especially when a beaver sits upright on land. Enamel on the front of the teeth gives them their distinctive orange-yellow hue.
How can you tell male and female beavers apart?
Visual distinction between male and female American Beavers is difficult in the field. Females are generally smaller than males, but the difference is subtle without a direct comparison. The most reliable way to identify sex is through direct observation of behavior (females with kits) or capture, which is not practical for wildlife watching.
Why don't beavers live in Oregon's ocean areas?
American Beavers are strictly freshwater animals. They lack the physiological adaptations (salt gland, salt-tolerant kidneys) that marine mammals possess, so saltwater would dehydrate them. They are found in rivers, streams, lakes, and wetlands throughout Oregon's interior and coast ranges, but never in tidal zones or open ocean. Coastal sightings are limited to freshwater tributaries and wetlands near the shore.
What other animals might be mistaken for beavers in Oregon?
Muskrats and nutria are much smaller (2 to 4 pounds) and have thin tails. River otters are sleek and slender, lack the large front teeth, and have long, tapered tails. Groundhogs and porcupines are terrestrial and do not spend significant time in water. Any large, flat-tailed rodent in an Oregon waterway is almost certainly an American Beaver.
When can you see beavers most easily in Oregon?
Beavers are most active during dawn and dusk, but activity and visibility peak from March through May, when water levels are highest from spring snowmelt and rainfall. This is also when they are rebuilding and repairing dams that may have been damaged by winter. Summer and fall offer occasional sightings along rivers and streams where trees show fresh beaver damage.
Do beavers in Oregon live alone or in families?
American Beavers live in family groups called colonies, typically consisting of a breeding pair and their offspring from the current and previous year. Colonies usually number 5 to 8 individuals but can be larger in resource-rich areas. Each colony maintains a territory and dam system, defending it against other beaver families. Young beavers leave the colony around age two to find new territory and mates.
Conservation status, source NatureServe
Conservation rank for beaver (American Beaver, Castor canadensis), as assessed by NatureServe Explorer.
| Scope | NatureServe rank | Meaning |
|---|---|---|
| In Oregon | S5 | Secure |
| Global (rangewide) | G5 | Secure |
NatureServe ranks run from 1 (critically imperiled) to 5 (secure). See our data methodology for how this is sourced.
Frequently asked questions
Is there more than one species of beaver in Oregon?+
No. The American Beaver is the only beaver species in Oregon and throughout the Pacific Northwest. This single species is found in suitable freshwater habitats across the entire state. You will never encounter a different beaver species in Oregon waters.
What size are beavers in Oregon?+
American Beavers in Oregon average 35 to 66 pounds, with females typically smaller than males. Full-grown adults can reach 3 to 4 feet in body length, not counting the tail. Their tail adds another 10 to 20 inches. These measurements make them the largest living rodent in North America and easily the largest rodent in Oregon.
What are beaver teeth like?+
Both upper and lower front teeth are large, prominent orange incisors that continue growing throughout life. These teeth are self-sharpening and capable of felling trees ranging from saplings to 6 inches in diameter. The teeth are visible from a distance, especially when a beaver sits upright on land. Enamel on the front of the teeth gives them their distinctive orange-yellow hue.
How can you tell male and female beavers apart?+
Visual distinction between male and female American Beavers is difficult in the field. Females are generally smaller than males, but the difference is subtle without a direct comparison. The most reliable way to identify sex is through direct observation of behavior (females with kits) or capture, which is not practical for wildlife watching.
Why don't beavers live in Oregon's ocean areas?+
American Beavers are strictly freshwater animals. They lack the physiological adaptations (salt gland, salt-tolerant kidneys) that marine mammals possess, so saltwater would dehydrate them. They are found in rivers, streams, lakes, and wetlands throughout Oregon's interior and coast ranges, but never in tidal zones or open ocean. Coastal sightings are limited to freshwater tributaries and wetlands near the shore.
What other animals might be mistaken for beavers in Oregon?+
Muskrats and nutria are much smaller (2 to 4 pounds) and have thin tails. River otters are sleek and slender, lack the large front teeth, and have long, tapered tails. Groundhogs and porcupines are terrestrial and do not spend significant time in water. Any large, flat-tailed rodent in an Oregon waterway is almost certainly an American Beaver.
When can you see beavers most easily in Oregon?+
Beavers are most active during dawn and dusk, but activity and visibility peak from March through May, when water levels are highest from spring snowmelt and rainfall. This is also when they are rebuilding and repairing dams that may have been damaged by winter. Summer and fall offer occasional sightings along rivers and streams where trees show fresh beaver damage.
Do beavers in Oregon live alone or in families?+
American Beavers live in family groups called colonies, typically consisting of a breeding pair and their offspring from the current and previous year. Colonies usually number 5 to 8 individuals but can be larger in resource-rich areas. Each colony maintains a territory and dam system, defending it against other beaver families. Young beavers leave the colony around age two to find new territory and mates.
Keep exploring
More wildlife in Oregon