MUSKOX (Ovibos moschatus)

RANGE: Canada, Greenland and Alaska.

The muskox, which is closely related to sheep and goats, was a contemporary of the mammoth during the ice ages and is one of the few large mammals capable of living year-round in the severe Arctic environment. Its thick outer coat of coarse hair reaches almost to the ground and protects it from snow and rain, and the soft, brownish, wool-like underhair is prized for its warmth. Muskoxen graze in moist lowlands and river valleys during summer and move to upland slopes and plateaus in winter, where high winds prevent the accumulation of deep snow and make foraging easier. When the herd is threatened by wolves or bears, adult muskoxen face outward to form a tight circle around the calves, which is an effective defense against predators but not human hunters. Due to overhunting in the 1800s and 1900s, muskoxen were exterminated in Alaska, northern Europe and Siberia and remained only in Greenland and Canada. Regulated hunting and reintroductions of muskoxen into their former range have helped them recover in some areas. However, climate change and increased human activity in the Arctic pose new threats.

Muskoxen are not well adapted to breaking through snow or ice to reach moss and lichen forage food. As a result of climate change, increasingly frequent extreme winter weather events, including deep snow and freezing rain events that form ice crusts, are creating conditions that hinder muskoxen from reaching their food. Dramatic population crashes resulting from dense snow and freezing rain have hit herds in northern Greenland and Canada. For example, on Banks Island in the Canadian High Arctic, freezing rain—rain that percolated through snow cover and later froze—formed a thick ice layer that prevented muskoxen from reaching their forage plants. As a result, an estimated 20,000 animals starved to death in 2003. On Bathurst Island in the Canadian High Arctic, dense snow cover during three consecutive winters resulted in an 80-percent decline in the muskoxen population. Scientists predict that freezing rain events will increase in frequency and area in many parts of the Arctic, [1] raising concern for the muskox’s future.

Muskoxen also face increasing risks from parasites and predators as temperatures warm. Warmer temperatures speed up the larval development of a harmful lungworm parasite of the muskox, and increase the likelihood of infection since the slug that harbors the lungworm stays active longer on the muskox’s forage plants. [2] The muskoxen may also face higher predation risk by grizzly bears as bears move northward into the muskox’s tundra home.