National Geographic : 1988 Jun
CE AGE THROWBACKS show ing their classic defense pos ture, a herd of musk-oxen press tightly together in a line. They may also form a semicircle or a full circle to protect them selves from wolves, their chief predators. No one really knows how many of these burly beasts inhabit Ellesmere, since the expense of working this far north precludes an in-depth survey. In 1965 John Tener of the Canadian Wildlife Service estimated a population of 4,000, nearly half the total for all Arctic islands. By way of comparison, explorers in the region around the turn of the century killed more than a thousand musk-oxen for food. In 1986 I counted 183 on about 600 square miles of good range, or one animal for every 3.28 square miles. This underscores how musk oxen and other land mammals survive here, by living in rela tively low densities and covering a lot of ground. The first musk oxen I ever saw on Ellesmere disappeared the next day, even though it was April and I could see over the snow-covered ground for miles. It was clear from studying their tracks, however, how the shaggy creatures earn their daily supply of sedges and arctic wil low. They frequent windblown plains in winter and lower, wetter areas in summer, paw out the vegetation, munch it down, shuffle around a bit, and paw for more. Though Peary caribou eat some of the same foods, they feed on higher ground and avoid competition with musk-oxen. John Tener once judged that even those portions of Ellesmere suitable for musk-oxen may yield only a fraction of the for age produced on territory far ther south. It is hard to believe that such a large herd animal can survive in any numbers on so spare a diet. Bulls may weigh 600 pounds, females 400, and calves in summer about 100. If there is something about a musk-ox that makes it seem not all of one piece, that may be because it is related to both the genus Ovis (sheep) and the genus Bos (cattle), but belongs to nei ther and has its own classifica tion--Ovibos. Its nearest living relative is the takin, a goatlike creature of the Himalayas. The breeding season begins in June when bulls start to fight for possession of one or more cows; the impact of their head-on crashes has been heard half a mile away. Mating generally occurs in August, and calves are born from mid-April to mid June. Most cows bear their first calf when they reach the age of four. From then on they gener ally breed each year, except when winters are unusually severe. Wolf predation on musk-ox calves plays a significant role in the fluctuation of the herd's population. Our wolf pack led us on one incredible hunt during which they killed three of a herd's calves within a few min utes! But musk-oxen are by no means defenseless. Jim found a wolf skull with the tip of a musk-ox horn embedded under the jaw.