Mountain Beaver
Aplodontia rufa
Aplodontia rufa are stout-bodied, tailless rodents, often described as resembling a large, short-eared guinea pig. They have a stocky build, small eyes, and short, rounde…

How to identify
Aplodontia rufa are stout-bodied, tailless rodents, often described as resembling a large, short-eared guinea pig. They have a stocky build, small eyes, and short, rounded ears. Their fur is coarse and ranges in color from reddish-brown to dark brown or grayish. They have distinctive, flattened skulls and unique teeth adapted for grinding tough vegetation.
Range
Aplodontia rufa, commonly known as the mountain beaver, is endemic to western North America. Their distribution extends along the Pacific coast from southwestern British Columbia in Canada, through Washington, Oregon, and into northern California in the United States. Isolated populations also occur in the Sierra Nevada Mountains.
Habitat
Aplodontia rufa are typically found in moist, coniferous forests and brushy areas with dense undergrowth in mountainous regions. They are semi-fossorial, creating extensive burrow systems with multiple entrances, nesting chambers, and food storage areas. They prefer areas with readily available vegetation and loose, damp soil suitable for digging. They are often associated with the presence of streams or other water sources.
Similar species
Within their range, Aplodontia rufa are quite distinct. Their tailless, stout body and specific habitat preferences help differentiate them from other rodents. Beavers are much larger, have a broad, flat tail, and are strongly associated with aquatic environments. Muskrats are also semi-aquatic and have a long, flattened tail.
Name and etymology
Genus
Aplodontia
Greek for simple (haploos) tooth (odous)
Origin
Sources
- Palmer, Index Generum Mammalium (1904) ↗
Palmer, T. S. 1904. Index Generum Mammalium: a list of the genera and families of mammals. North American Fauna 23. Government Printing Office, Washington. https://doi.org/10.5962/bhl.title.39809
Species epithet
rufa
Latin for reddish or red-haired
Origin
Sources
- Wikipedia: Aplodontia rufa ↗
“Aplodontia rufa.” Wikipedia. https://en.wikipedia.org/wiki/Mountain_beaver
Explore more names in the etymology index.
At a glance
Range
Aplodontia rufa, commonly known as the mountain beaver, is endemic to western North America. Their distribution extends along…
Habitat
Aplodontia rufa are typically found in moist, coniferous forests and brushy areas with dense undergrowth in mountainous regio…
Guide
Mammals of North America
Range map

Approximate range. © Mapbox © OpenStreetMap
