gray fox

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

• noun Any of several foxes having grizzled fur on the back and sides, especially Urocyon cinereoargenteus of southern North America, Central America, and northern South America, which has a black stripe down the tail and, unlike the red fox, climbs trees.

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

• noun dark grey American fox; from Central America through southern United States