(species Alopex lagopus), northern fox of the family Canidae, found throughout the Arctic, usually on tundra or mountains near the sea. In adaptation to the climate, it has short, rounded ears, a short muzzle, and fur-covered soles. Its length is about 50–60 cm (20–24 inches), exclusive of the 30-centimetre tail; and its weight is about 3–8 kg (6.6–17 pounds). coloration depends on whether the animal is of the “white” or the “blue” colour phase. Individuals of the white phase are grayish brown in summer and white in winter (see photograph-->), while those of the blue phase (blue foxes of the fur trade) are grayish in summer and gray-blue in winter.