Muskox bulls reach weights of about 380 kg (835 lb.) and stand up to 1.5 m (5 ft.) at the shoulder. Cows are about 60% of the weight of bulls and stand about 1.2 m (4 ft.) at the shoulder.

Adult males have massive horn bases, which are used in head-on clashes during fights over herd leadership. The sharp horn tips of the adults are used primarily in defence against wolves and polar bears, their only predatory enemies besides humans.

Muskoxen are renowned for their underfur of extremely fine and long hair. This thick undercoat is covered by long guard hairs and protects the muskox during long, cold winters. Humans prize it because it can be spun into very warm and lightweight fabrics.

This shaggy, wild relative of sheep and goats lives in herds on the tundra in the Canadian Arctic. It inhabits eastern Greenland and the Arctic islands of Canada and has been successfully introduced into northern Quebec, western Greenland, northern Europe and Russia, and reintroduced into its former range in Alaska. Near extinction in the early 1900s, thanks to protection from hunting and re-introductions the populations are increasing.

Learn about prehistoric populations.