mountain beaver

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A stout burrowing rodent (Aplodontia rufa) of the Pacific coast of North America, having small eyes and ears and feeding on vegetation such as ferns and tree seedlings.

from The Century Dictionary.

• noun The sewellel, Haplodon rufus. See sewellel, and cut under Haplodon.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun bulky nocturnal burrowing rodent of uplands of the Pacific coast of North America; the most primitive living rodent