Smithsonian National Museum of Natural History, North American Mammals

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  Rodentia · Aplodontidae · Aplodontia rufa

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Aplodontia rufa


Order: Rodentia
Family: Aplodontidae

Click to see adaptations.   
Image of Aplodontia rufa
Click to enlarge. (143 kb)

Conservation Status: Least Concern.

Some scientists think the Sewellel is the world's most primitive living rodent, similar in appearance and behavior to animals that lived 60 million years ago. They have small eyes and ears and luxurious whiskers, and are, like many other burrowing rodents, armed with good senses of smell and touch. They rely much less on sight and hearing. They eat plants, including bark, and are able to feed on species such as rhododendron and stinging nettle, which are toxic or noxious to many other mammals. Sewellels are found in coniferous forest at all elevations. Although their geographic distribution is limited, they are common within their range. They are not closely related to water-dwelling beavers (genus Castor), although both are rodents.

Also known as:
Mountain Beaver, Boomer

Average: 354 mm
Range: 238-470 mm

Average: 1,065 g
Range: 806-1,325 g


Rafinesque, C.S., 1817.  Descriptions of seven new genera of North American quadrupeds, p. 45.  American Monthly Magazine and Critical Review, 2(1):44-46.


Mammal Species of the World (opens in a new window).

Mammalian Species, American Society of Mammalogists' species account *
* PDF reader available here (opens in a new window).

Distribution of Aplodontia rufa

Image of Aplodontia rufa
Click to enlarge. (70kb)

Image of Aplodontia rufa
Click to enlarge. (181kb)

Skull of Aplodontia rufa
Click to enlarge. (17kb)