206 WILD NEIGHBORS CHAP, VIL 
Our common porcupine of the eastern United 
States and Canada (Erethizon dorsatus) once 
ranged over all the forested parts of the country 
north of Virginia and Kentucky; it seems to reach 
northward nearly or quite to the limit of forest- 
growth, having been reported from the Mackenzie 
valley. Along the Missouri River it mingles spar- 
ingly with a second, Western species, the yellow- 
haired (Evethizon epixanthus), which ranges across 
the Plains to the Rocky Mountains, and to all 
parts of the Pacific Coast southward as far as the 
Mexican border. Godman, Audubon, and the older 
writers, so far as they spoke of this latter animal 
at all, confused it with the Eastern form. 
