What is "mountain beaver"

Sewellel \Se*wel"lel\, n. [Of American Indian origin.] (Zo["o]l.) A peculiar gregarious burrowing rodent ( Haplodon rufus), native of the coast region of the Northwestern United States. It somewhat resembles a muskrat or marmot, but has only a rudimentary tail. Its head is broad, its eyes are small and its fur is brownish above, gray beneath. It constitutes the family Haplodontid[ae]. Called also boomer, showt'l, and mountain beaver.

n. A rodent found on the west coast of North America, taxonomic name ''Aplodontia rufa''. It is not part of the beaver family.

n. bulky nocturnal burrowing rodent of uplands of the Pacific coast of North America; the most primitive living rodent [syn: sewellel, Aplodontia rufa]

The mountain beaver (Aplodontia rufa) is a North American rodent. It has several common names, including: aplodontia, mountain boomer, ground bear, and giant mole. The name sewellel beaver comes from sewellel or suwellel, the Chinookan term for a cloak made from its pelts. This species is the only living member of its genus, Aplodontia, and family, Aplodontiidae. It should not be confused with true North American and Eurasian beavers, to which it is not closely related.