Lagopus term is of feminine gender, and the specific epithet has to agree with that, the feminine "muta" and "leucura" are correct. The English name "ptarmigan" comes from the Scottish Gaelic name for the bird, , whose origin is unknown. The p- was added due to a mistaken belief in a Greek origin, as if the word were related to the Greek word ("pterón"), 'wing'. The three species are all sedentary specialists of cold regions. Willow ptarmigan is a circumpolar boreal forest species, white-tailed ptarmigan is a North American alpine bird, and rock ptarmigan breeds in both Arctic and mountain habitats
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,