The muskox (Ovibos moschatus) is an Arctic mammal of the Bovidae family, noted for its thick coat and for the strong odor emitted by males, from which its name derives. This musky odor is used to attract females during mating season.
Muskoxen are social and live in herds, usually of around 10–20 animals, but sometimes over 70. Winter herds consist of adults of both sexes as well as young animals. During the mating season, which peaks in mid-August, males compete for dominance, and one dominant bull drives other adult males out of the group. Non-breeding males will often form male only herds of 3-10 or wander the tundra alone. During this period all males are extremely aggressive. Bulls will even charge birds if they are close by.
Females are sexually mature at two years of age, and males reach sexual maturity after five years. The gestation period is eight or nine months. Almost all pregnancies yield single calves. The young nurse for a year, but may start to eat grasses as soon as a week after birth.
Muskoxen have a distinctive defensive behavior: when the herd is threatened, the bulls and cows will face outward to form a stationary ring around the calves. This is an effective defense against predators such as wolves, but makes them an easy target for human hunters.
The muskox, or its ancestor, is believed to have migrated to North America between 200,000 and 90,000 years ago. It is agreed however that the muskox was alive in the Pleistocene period making it a contemporary of the Mammoth. It is thought that the muskox was able to survive the last ice age (Wisconsin glaciation) by finding ice free areas away from prehistoric peoples. The muskox gradually moved across North America and arrived in Greenland during the late Holocene.
Muskoxen are native to the Arctic areas of Canada, Greenland, and Alaska. The Alaska population was wiped out in the late 19th or early 20th century, but muskoxen have since been reintroduced to Alaska. The United States Fish and Wildlife Service introduced muskox onto the Nunivak Island in 1935 as a means for sustenance living. The species has also been reintroduced from Banks Island to northern Europe, including Sweden, Estonia, the Dovre region of Norway, and Russia and from Ellesmere Island to Eastern Canada. In the province of Quebec, muskoxen were close to extinction at one point, but have recovered after being protected from hunting. The world population is estimated at between 80,000 and 125,000, with an estimated 68,788 living on Banks Island.
During the summer, muskoxen live in wet areas, such as river valleys, moving to higher elevations in the winter to avoid deep snow. They graze on grasses, reeds, sedges, and other ground plants, digging through snow in the winter to reach their food.