Oregon mammals

Mountain Beaver in Oregon

Aplodontia rufa

Native to Oregon S4 Apparently Secure in Oregon

Not listed as nonindigenous in Oregon by USGS NAS; native to its Oregon range.

IUCN Red List status

NE – Not Evaluated

Not yet assessed against IUCN Red List criteria.

Photo: Huck · CC0Live mountain beaver sitting alert on damp grassy ground in daylightPhoto: AJ Beavan · CC0Live mountain beaver foraging among green foliage in profilePhoto: John Brew · CC BY 4.0Live mountain beaver among buttercup leaves with its head raisedPhoto: M · CC BY 4.0Live mountain beaver at the mouth of its burrow beneath a rotting log

Mountain Beaver in Oregon, by the numbers

Occasional in Oregon 69th most recorded of 178 mammals logged in Oregon

495 occurrence records

136 with iNaturalist photos

Jul 3, 2026 Last seen in Oregon

Records from 2000–2026.

495 total records count every Oregon occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 483 records with a full observation date.

When to look for the Mountain Beaver in Oregon

Most sightings fall in July to August.

483 Oregon occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly Oregon records (table)

Month	Records
January	33
February	26
March	23
April	30
May	31
June	44
July	86
August	82
September	18
October	20
November	45
December	45

Monthly mountain beaver occurrence records (iNaturalist and GBIF) in Oregon, 2000–2026.

Seasonality

Year-round in Oregon, with recorded sightings peaking in July–August.

Occurrence map

Where Mountain Beaver has been recorded in Oregon

300 records mapped · zoom and drag to explore

300 Oregon records mapped

Notable places to look

Park, forest, or monument	iNaturalist records
Siuslaw National Forest	40
Mt. Hood National Forest	4
Rock Creek Wilderness	4
Oregon Caves National Monument and Preserve	3
Cascade Range	2
Grassy Knob Wilderness	2
Mount Hood Wilderness	2
Columbia River Gorge National Scenic Area	1

Protected places with the most mountain beaver sightings, from the USGS Protected Areas Database plus named mountain ranges, good spots to look, not a full breakdown, so they don't sum to the total.

Where it's recorded in Oregon

County	Records
Lane County	76
Lincoln County	69
Benton County	47
Tillamook County	43
Clackamas County	40
Coos County	39
Douglas County	36
Clatsop County	29
Columbia County	23
Curry County	18
Multnomah County	11
Washington County	11
10 other counties	53

The complete county distribution, spread across 22 Oregon counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Mountain-beaver records form a distinctly western Oregon pattern, running through the moist Cascades from Mount Hood and the Columbia River Gorge into Willamette National Forest. Unlike several alpine mammals in the ranking, this species is documented as a year-round resident, with local timing likely shifting with elevation and forest conditions. The footprint represents reported encounters with an inconspicuous burrower, not its abundance across those forests.

Occurrence data from iNaturalist and GBIF.

Full species profile Mountain Beaver Aplodontia rufa Size 38.3 cm15.1 in Weight 500–900 g1.1–2 lb Lifespan Up to 10 yr View the full profile

More mammals in Oregon in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
NatureServe ExplorerCC-BYthe state conservation rank
IUCN Red Listattributed factthe global conservation status
USGS NASpublic domainnative / introduced status
Natural Earthpublic domainthe relief basemap
USFSpublic domainnational-forest boundaries
USGS Protected Areas Databasepublic domainthe named parks, forests, and refuges behind "notable places to look"