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Muskoxen or muskox (Ovibos moschatus) are a species of large mammal in the family Bovidae, which also includes cattle, buffalo, antelope, sheep, and goats. The muskox is anatomically intermediate between sheep and cattle, and there has been taxonomic debate over which of these two groups the muskox should be more closely aligned with. As a result, its genus, Ovibos, is a composite of the scientifically Latinized words for sheep (Ovis) and cattle (Bos).

Muskoxen are arctic and subarctic animals of the Northern Hemisphere, historically occurring in both North America and Eurasia. Muskox had been extirpated from Eurasia, but have recently been re-introduced into Siberia from North American stock. For millennia up to about 8,000-10,000 years ago during and soon after the most recent Pleistocene glaciation, muskox were a component of a relatively diverse fauna of large animals of the northern regions. During that time, muskox and caribou ranged throughout much of the northern United States, Canada, Germany, France, Britain, Poland, Scandinavia, Ukraine, Belarus, and northern Russia, as did woolly rhinoceros, mastodon, mammoths, and other now-extinct large mammals. The reasons for the apparently simultaneous extinction of most of the species of this diverse mammalian fauna are not known. One popular hypothesis is that these species were overhunted by predatory humans; however, other environmental factors, perhaps associated with climate change, may also have been important. In some respects, muskox and caribou can be considered relics of this extraordinary ice-age fauna.

Muskox are large animals, with the biggest bulls measuring up to 7.5 ft (2.5 m) in body length, standing as tall as 4.5 ft (1.5 m) at the shoulder, and weighing as Muskoxen, when threatened, form a defensive circle. JLM Visuals. Reproduced by permission.

much as about 1,400 lb (650 kg). Muskox have an extremely heavy pelage, consisting of coarse, dark brown, guard hairs, and an extremely soft and fine inner fleece that is virtually impenetrable to cold and moisture. Both sexes have horns that curve broadly downward and then up, but the bull's horns are especially massive, and meet at the forehead. The horns are keratinized, meaning they are anatomically derived from fused hairs, rather than from the skull bones, as in deer (family Cervidae). Muskox have a superficially clumsy appearance, but when pressed they are nimble and fleet runners, even on very uneven and wet terrain.

Muskox are herding animals, sometimes occurring in groups of as many as 100 individuals, but more often they are found in herds of 10-15 or fewer. Usually, these groups consist of mature bulls protecting their harem of mature cows, calves, and immature offspring of various ages. As the young males mature and become potential competitors for females, they are driven from the herd by the dominant bull. The young bulls then form their own small herds; and as they age and grow stronger, the younger males challenge the dominant bull, eventually taking over the harem. Once driven off, the older bull muskoxen lead a solitary, wandering life.

When confronted by predators, muskox herds usually form a tight defensive circle or line, with young calves protected in the center and mature animals on the periphery. This behavior provides a formidable barrier against natural predators such as wolves. However, humans armed with rifles can wipe out an entire herd because the ring often does not break up, and animals do not flee as their partners are killed.

During the summer, muskox primarily graze on grasses, sedges, and forbs (i.e., herbaceous dicotyledonous plants). During the winter, they mostly browse on woody shrubs; however, in the high-arctic portions of their range, where shrubs are uncommon and vegetation is generally sparse, muskox must make do with lichens and any other vegetation that can be obtained. Muskox paw through the surface snow to obtain food during winter. If the snow is icy, the animals feed on plants on exposed ridges and plateaus, where snow cover is thinner. Muskox do not undertake extensive migrations, though they do move locally between winter and summer ranges.

During the nineteenth century, the muskoxen of northern North America were heavily hunted for their hides and meat, and their populations declined drastically. More recently, however, measures to conserve the species have allowed their populations to increase, and muskox are now expanding their range to re-occupy previously used habitat. This species is now sustainably hunted for subsistence and sport. There is even a small hunt conducted by Canadian Inuit to ship meat to southern markets, where muskox is considered to be an exotic food.



Banfield, A.W.F. The Mammals of Canada. Toronto: University of Toronto Press, 1974.

Grzimek, B., ed. Grzimek's Encyclopaedia of Mammals. London: McGraw Hill, 1990.

Wilson, D.E., and D. Reeder. Mammal Species of the World. 2nd ed. Washington: Smithsonian Institution Press, 1993.

Bill Freedman

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