Every year, when the first wave of Arctic air drops into the Heartland, I am inclined to consider those mammals that are able to thrive in such brutal conditions. Of those that survived the Pleistocene and still inhabit the Arctic, the muskox always comes to mind. Best known for their shaggy coats and defensive behavior, muskoxen are closely related to mountain goats and mountain sheep (as is evident from the permanent horns of both genders).
Having evolved in northern Asia, the muskox, like the woolly mammoth, crossed into North America during the Pleistocene when the Bering land bridge connected the two Continents. While they died out in Asia and Alaska, these hardy animals survived across Arctic Canada and Greenland despite harsh conditions and determined predators (including wolves, bears and humans). During the latter half of the 20th Century, muskox herds were successfully re-established in Russia and Alaska and others were transplanted to Scandinavia; most of these herds have been domesticated for their meat, milk and qiviut, among the finest wools on our planet.
Like American elk, muskox males gather harems during their breeding season, which occurs in August and September. Depending upon food availability (grasses, herbs, mosses, willows), females generally breed by age three and do so every 2-3 years; a single calf is born in late spring. While muskoxen are known to live up to 20 years in the wild, most succumb to predators, injuries or starvation at a much younger age. When threatened, muskoxen form a defensive circle with the bulls and cows facing outward and the young in the center.
