Northern fox ( Alopex lagopus ) found throughout the Arctic, usually on tundra or mountains near the sea.
Its short, rounded ears and short muzzle reduce its body area exposed to heat loss, and it has fur-covered soles. It is 20–24 in. (50–60 cm) long (excluding the 12-in., or 30-cm, tail) and weighs 7–17 lbs (3–8 kg). It has two colour phases. Individuals in the white phase are grayish brown in summer and white in winter; those in the blue phase (blue foxes of the fur trade) are grayish in summer and gray-blue in winter. The Arctic fox dwells in burrows and feeds on any available animal or vegetable material.