While Erdrich may not give us a physical description of the Windigo in her introduction, from her descriptions within the poem we can tell that the Windigo resembles some sort of furry beast, like a wolf, or maybe even a Sasquatch-type creature—or maybe a furry beast that makes Sasquatch look like a baby Ewok. This bestial imagery, however, recurs throughout the poem, even in descriptions of the landscape and setting.
Line 6: Here Erdrich uses the word "hackles," a term most often used to describe the upright hair on the back of a distressed or agitated dog or wolf. So when Erdrich writes about the "hackles of dry brush," setting the scene for the entry of the Windigo, we know there is cause for alarm.
Line 15: This is the first reference in the poem to the Windigo's actual physical description. Fur… like a wolf? Like a Sasquatch? Like werewolf Michael Jackson in the "Thriller" video?
Line 16: The word "bristling" again invokes the look of an agitated canine, an imposing beast with fur thick and imposing as armor.