Willow ptarmigan by the fact that it is not generally found above the tree line while the rock ptarmigan prefers more elevated, barren habitat. The summer plumage is browner and in the winter, the male willow ptarmigan lacks the rock ptarmigan's black stripe between the eyes and bill. The white-tailed ptarmigan ("Lagopus leucura") in North America is smaller, has a white tail and finely-barred greyer plumage and lives permanently above the tree line. The distinctive British Isles subspecies "L. l. scoticus" (red grouse) was once considered a separate true British species but is now classified as a sub-species. This moorland bird is
Arctic hare new fur, from brown or grey in the summer to white in the winter, like some other Arctic animals including ermine and ptarmigan, enabling it to remain camouflaged as their environments change. However, the Arctic hares in the far north of Canada, where summer is very short, remain white all year round. The Arctic hare is one of the largest living lagomorphs. On average, this species measures from long, not counting a tail length of . The body mass of this species is typically between , though large individuals can weigh up to . The Arctic hare is a herbivore,