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 fox regulation. Also, the Arctic fox has a beneficial mechanism in their nose for evaporative cooling like dogs, which keeps the brain cool during the summer and exercise. The thermal conductivity of Arctic fox fur in the summer and winter is the same; however, the thermal conductance of the Arctic fox in the winter is lower than the summer since fur thickness increases by 140%. In the summer, the thermal conductance of the Arctic foxes body is 114% higher than the winter, but their body core temperature is constant year-round. One way that Arctic foxes regulate their body temperature is by