Species MammalsMountain Beaver

Mountain Beaver

Aplodontia rufa

UncommonMammal
Illustration of Mountain Beaver (Aplodontia rufa)

The Mountain Beaver is neither a true beaver nor a mountain dweller but is in fact the world's most primitive living rodent—the sole surviving member of a once-diverse family with a fossil record stretching back 40 million years. It burrows in moist forests along the Pacific Coast and must drink water frequently, unable to concentrate its urine effectively. Mountain beavers are important ecosystem engineers in Pacific Coast forests, creating habitat features used by many other species.

Habitat
Moist Pacific Coast conifer forests with dense fern understory
Diet
Ferns, forbs, bark, and needles of conifers
How common
Uncommon

Best time to see a Mountain Beaver

The best time to see a Mountain Beaver is April–August, when about 65% of U.S. sightings happen, based on 375 research-grade iNaturalist observations.

J
F
M
A
M
J
J
A
S
O
N
D

Not certain it is a Mountain Beaver? What animal is this? walks through what to check first and the lookalikes that catch people out.

Recent Mountain Beaver sightings near you

Live, research-grade observations from iNaturalist. Allow location to center the map on you.

Spot a Mountain Beaver? Identify it instantly.

Point Huck at any plant, bird, or animal for an instant ID, its rarity, and a live map of where it is being seen near you.

Get Huck

Get an alert when a Mountain Beaver is spotted

Pick a park, state, or city and we’ll email you when one turns up there. One check a day, only when there’s something new.

Free. Unsubscribe from any email. See our Privacy Policy.

Love mammals? Get Huck field notes

Spotting tips, new species, and the best of what people are finding in the wild - straight to your inbox.

By subscribing you agree to receive Huck emails. No spam, unsubscribe anytime. See our Privacy Policy.

More mammals

Mountain Coati
Mountain Coati
Nasuella olivacea
Mountain Cottontail
Mountain Cottontail
Sylvilagus nuttallii
Mountain Goat
Mountain Goat
Oreamnos americanus
Mountain Lion
Mountain Lion
Puma concolor
Mule Deer
Mule Deer
Odocoileus hemionus
Musk Ox
Musk Ox
Ovibos moschatus
Muskrat
Muskrat
Ondatra zibethicus
Naked-footed Deer Mouse
Naked-footed Deer Mouse
Peromyscus nudipes