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Although its scientific name literally means "musky sheep-ox," the muskox more closely resembles cattle and is more closely related to sheep and goats than other oxen. The common name is quite appropriate, however, as rutting bulls do emit a strong musky odor that can be smelled up to 100 yards away.
A muskox bull can stand 4.5 feet at the shoulder, which has a slight hump, be 8 feet long, and weigh over 800 pounds; cows are slightly smaller. Both sexes have pale yellow horns that are joined at the base and then grow sideways, downwards, and backwards until the tips are level with the bases, but those of males are much heavier than females' and the base is much more pronounced. The muskox has short, sturdy legs and broad hooves.
The muskox's dense woolly undercoat is impervious to dampness and cold. That coat is coverered by a shaggy dark-brown mantle of long guard hairs that often brushes the ground. Those two coats allow muskox to survive in the arctic tundra, where winter temperatures can average -70º F and winter storms can last for several day. The back is marked by a lighter colored patch of brown or cream where the guard hairs are shorter. Older adult muskoxen sometimes develop a large mane of fur that sits on the shoulders.
Distribution and Habitat
The muskox is native to the arctic tundra of Alaska, Canada, and Greenland, and has been introduced into Russia, Svalbard, Norway, and Siberia. Some herds have also found their own way from Norway into Sweden.
Contrary to many species, the musk ox migrates from sheltered, moist lowlands in the summer to higher, barren plateaus in winter. The primary reason for this is food, as the exposed plateaus do not accumulate snow due to the high winds, making food easier to find. The distance traveled between summer and winter areas generally does not exceed 48 miles.
Habits and Behaviors
Muskoxen live in herds as small as 5 animals during the summer, and may join with other small groups to form herds as large as 60 individuals in the winter. These larger groups help provide protection from both the elements and predators. Most herds average between 10 and 20 animals.
Social hierarchy in the herd is based upon dominance. Dominance among males is typically determined during the breeding season, and sometimes throughout the year through headbutting and chasing, as well as grunting and bellows. Among females, dominance is determined by age and size, with the larger, older females typically exerting dominance over younger, smaller, females through pushing, shoving, and chasing. Calves are generally lowest in the hierarchy, although they determine dominance amongst themselves through chasing, mounting, and play. Generally, the higher the dominance status of the muskox, the better its food supply and breeding rights.
Although capable of running as fast as 25 miles per hour, muskoxen do not run from danger. They prefer instead to "face down" intruders and predators by forming a tight circle of bulls around the cows and calves and lunging en masse at the intruder. Such displays tend to dissuade all but the most persistent predators.
Calves, when communicating with cows or each other, bleat, the pitch of which lowers with maturity. Adults have deeper voices that sound closer to roars and rumbles that can be heard long distances. Adults also grunt and snort at each other, at calves, and at other animals. Pushing and shoving, as well as chasing and stomping, are used to communicate dominance.
During the rut, bulls fight for possession of the herds by ramming each other head-on with such force that the impacts can be heard over a mile away. The bulls' heavy horns and "base plates" prevent injury during the battle, which will continue until one of the males backs down. Males that compete for dominance are typically between the ages of 6 and 8 years old, as older bulls are usually not strong enough, and younger males are typically not large enough, to compete. Defeated males tend to stay away from the main herd during the remainder of the breeding season, but often rejoin once the rut is over. Dominant bulls can become so protective of their cows that they will even chase away birds that get too close.
Mating takes place in August and September and a single calf is born the following April or May. The precocious calf has a thick woolly coat and can follow its mother at an hour old and begins nibbling on plants at about a week. It will continue to nurse for up to a year, however, and will stay close to its mother until at least 18 months of age. Cows mature at 1-4 years, depending on body condition. They only calve every other year, unless the calf is lost in its early months. Bulls mature at 3-4 years. Musk ox can live 20 years or more.
Muskoxen are generalized grazers. In the summer months, the diet includes grasses, leafy plants, sedges, mosses, shrubs, herbs, and generally any vegetation available. In the winter months, the diet changes to willow, dwarf birch stems, roots, mosses, lichen, and any vegetation they can locate under or above the snow.
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This page was last updated on August 31, 2018.