Muskox

• 1. Introduction

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  In the Inuktitut language, the muskox is called umingmak, which means "the bearded one". Woods Cree speakers had two names for it. One was mâthi-môs, "ugly moose", and the other was mâthi-mostos, "ugly bison". Scientists know the animal as Ovibos moschatus, a hoofed Arctic mammal of the family Bovidae. Its English name comes from something a visitor would notice before anything else, the odor that males give off during the seasonal rut.

  This shaggy animal outlasted much of the Ice Age's giant fauna. Then, thousands of years later, people carried it back to places it had long since left. Who are its true relatives, and why does the name mislead? How does a body keep working in Arctic cold? What happened when governments, farmers and scientists began moving herds around? And what do the animals do when a predator approaches?

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• 2. Family Tree

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  Despite the ox in its name, the muskox is more closely related to sheep and goats than to cattle. Its genus, Ovibos, takes its name from Latin and means "sheep-ox". Only one other living member of its group matches it for size, the takin, which belongs to the genus Budorcas.

  For a time, the takin and the muskox were thought to be close kin. The takin lacks features that define the muskox, such as its specialized horn structure. Genetic analysis shows that the two lineages separated early in caprine evolution. The muskox's nearest living relatives are the gorals, genus Naemorhedus, which are common across central and east Asia. The resemblance to the takin is convergent evolution.

  The family line that led to the muskox began in the temperate forests of Asia. During the Pliocene, its early members left for the developing grasslands of Central Asia. From there they spread into Siberia and the rest of northern Eurasia. Adapting to cold tundra came late in the line's history.

  Euceratherium, the "shrub-ox", crossed to North America over an early Bering Land Bridge two million years ago. It was larger than a modern muskox but more lightly built, rather like a giant sheep with massive horns. It preferred hilly grasslands and prospered in the American southwest and Mexico. It lasted until the Pleistocene-Holocene extinction event.

  Soergelia had horns of intermediate shape and lived from Spain to Siberia in the early Pleistocene. It also crossed into North America, during the Irvingtonian, which runs from 1.8 million to 240,000 years ago. It was a lowland dweller and disappeared fairly early, displaced by the "giant muskox" Praeovibos, whose name means "before Ovibos".

  Praeovibos had low-set horns. It lived in Europe and the Mediterranean 1.5 million years ago, reached Alaska and the Yukon one million years ago, and vanished half a million years ago. It was highly adaptable, found with reindeer faunas of the cold tundra and with red deer faunas of temperate woodland. In eastern Siberia's Kolyma river area, 500,000 years ago, it lived beside wild horses, reindeer, woolly mammoths and stag-moose. Scientists still debate whether it was a direct ancestor of Ovibos or whether both descend from a shared ancestor.

  Two more relatives were named in 19th-century America, Bootherium and Symbos. They are now understood to be the male and female forms of one species, the "woodland muskox", Bootherium bombifrons. It lived in open woodland from Alaska to Texas and perhaps Mexico, and it was most common in the southern United States. Ovibos replaced it on the tundra-steppe immediately south of the Laurentian ice sheet.

  Modern Ovibos appeared in Germany almost one million years ago and stayed common there through the Pleistocene. By the Mindel glaciation, it had reached the British Isles. Both lands lay just south of the Scandinavian ice sheet and turned to tundra in cold periods. Muskoxen are rarely recorded in milder, wooded France and Green Spain, where they shared the land with red deer and aurochs. In Britain, they survived warm interglacial periods too.

  Today's muskoxen descend from animals that took a different route, across the land bridge that once joined Siberia to Alaska.

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• 3. Retreat to the North

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  Between 200,000 and 90,000 years ago, the ancestors of today's muskoxen are believed to have crossed from Siberia into North America. Alaska, then joined to Siberia, had held muskoxen between 250,000 and 150,000 years ago. By 34,000 years ago, the species was already living on Banks Island, its stronghold today. Whether other ice-free areas existed in the Canadian Arctic Archipelago at that time is disputed.

  During the Wisconsinan, modern muskoxen thrived on the tundra south of the Laurentide Ice Sheet, in what is now the Midwest, the Appalachians and Virginia. They were always less common than other Ice Age megafauna. Their numbers peaked 20,000 years ago, during the Würm II glaciation, and then declined. At their widest, fossils show them from the Ural Mountains to Greenland.

  The muskox, the bison and the pronghorn were among the few North American Pleistocene megafauna to live through the extinction event that ended the epoch. The muskox is thought to have endured the last glacial period in ice-free refugia, away from prehistoric peoples. Only the North American populations survived.

  Fossil DNA shows that Pleistocene muskoxen were also more genetically diverse than those alive now. Research links colder periods in Earth's history to greater diversity and warmer periods to greater uniformity.

  The last known European population died out in Sweden 9,000 years ago. In Asia, the muskox held on much longer. The youngest natural records from the Taymyr Peninsula date to around 2,700 years ago. A find at Tumat, in the Sakha Republic, falls between 615 and 555 BC.

  As the Laurentide Ice Sheet disappeared, muskoxen moved gradually north across the Canadian Arctic Archipelago. They reached Greenland from Ellesmere Island around 350 AD. Their arrival in the northwest probably came within a few hundred years of the Dorset and Thule cultures settling near present-day Qaanaaq. Hunting around Qaanaaq may have kept the animals from spreading down the west coast, confining them to the northeastern fringes of the island.

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• 4. Built for the Cold

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  A muskox stands between 1.1 and 1.5 metres at the withers, yet its coat and large head make it look bigger than it is. Females measure 135-200 cm in length, and the larger males 200-250 cm. Both sexes carry long, curved horns. The tail is only 10 cm long and is often hidden under fur.

  The average adult weighs 285 kg, with a range from 180 to 410 kg. A bison, the animal it is most often compared to, can weigh up to twice as much. Heavy zoo specimens have reached 650 kg. The coat mixes black, gray and brown, and its long guard hairs almost reach the ground. Rare white muskoxen have been spotted in the Queen Maud Gulf Bird Sanctuary.

  Despite the bulk, a muskox can run at up to 60 km/h. Life expectancy runs from 12 to 20 years.

  Inside the body, the muskox is heterothermic. It can shut off temperature regulation in parts of the body such as the lower limbs. Keeping the legs cooler than the core reduces the heat lost through the extremities. Its hemoglobin is also three times less sensitive to temperature than human hemoglobin. That lets it hold oxygen tightly in extreme cold and keep delivering plenty to chilled tissue.

  In summer, muskoxen live in wet areas such as river valleys. In winter they move to higher ground to avoid deep snow. They eat grasses, arctic willows, woody plants, lichens and mosses, and they favor succulent, nutritious grasses when food is plentiful. Willows are the most commonly eaten plant in winter. Winter ranges tend to have shallow snow, which lowers the energy cost of digging for forage.

  A female needs a high threshold of fat reserves before she can conceive, which reflects a conservative breeding strategy. The main predators are arctic wolves, which may account for up to half of all deaths. Grizzly bears, polar bears and wolverines are occasional predators, likely mostly of calves and infirm adults.

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• 5. Herd Life

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  Muskox herds number 12-24 animals in winter and 8-20 in summer, when dominant bulls drive other males out. The animals hold no territories. Males and females each keep separate hierarchies ranked by age, with mature animals ruling over juveniles. Dominant animals get the best resources and push subordinates off winter grass patches.

  Bulls have several ways of asserting rank. In the "rush and butt", a dominant bull charges a subordinate from the side with its horns, giving a warning that lets the other escape. Bulls also roar, swing their heads and paw the ground. A dominant bull sometimes treats a subordinate like a cow. It taps him with a foreleg, as it would a cow during mating. A subordinate can challenge his status by charging.

  The rut begins in late June or early July. Dominant bulls fight rivals out of the herds and gather harems of usually six or seven cows with their offspring. Rival bulls bellow loudly and show their horns. Then they back up about 20 m, lower their heads and crash together, repeating the charge until one gives up. Defeated and elderly bulls leave to form bachelor groups or wander alone, though they may return to the herd when danger is near. During mating, a bull taps the cow with a foreleg to calm her. The herds reassemble when summer ends.

  Once the rut is over, the cows take charge. Pregnant females decide how far the herd travels each day and where it beds down. Herds move more often while cows are nursing, so mothers can find enough food. Gestation lasts eight to nine months, and calves arrive from April to June. Cows do not calve every year. After a severe winter, they will not come into estrus and so will not calve the next year.

  Muskoxen are precocial, and a calf can keep up with the herd within a few hours of birth. It nurses for the first two months, then starts eating vegetation and nurses only occasionally. Cows call to their calves by braying. The bond between mother and calf weakens after two years.

  When a herd is threatened, the adults face outward in a stationary ring or semicircle around the calves. Bulls usually form the front line, and cows and juveniles gather close to them. Bulls decide the formation during the rut, while cows decide it for the rest of the year.

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• 6. Chemistry of the Rut

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  Researchers have analyzed the secretion of the preorbital gland, found near the eye. They describe its odor as "light, sweetish, ethereal". The extract contained cholesterol, which is nonvolatile, and benzaldehyde. It also held a series of straight-chain saturated γ-lactones, ranging from C8H14O2 to C12H22O2. The most abundant was C10H18O2, and the monounsaturated γ-lactone C12H20O2 was probably present as well. The saturated lactone series smells much like the secretion itself.

  Muskoxen use these glands to mark their trails, and bulls rub them against their legs before fights. The smell that gives the species its name has a separate source. The odor of dominant, rutting males is described as "strong" and "rank". It comes from the preputial gland and is spread over the fur of the abdomen through urine.

  Extracts from washes of the prepuce revealed benzoic acid and p-cresol. They also revealed a series of straight-chain saturated hydrocarbons, from C22H46 to C32H66. The most abundant was C24H50.

  The purpose of all that chemistry is plain. The musky odor draws females during the mating season.

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• 7. Moved by Human Hands

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  In 1913, workers building a railway over Dovrefjell in Norway found two fossil muskox vertebrae. The discovery gave rise to the idea of bringing muskoxen from Greenland. The first release anywhere took place on Gurskøya, near Ålesund, in 1925-26, using animals caught by Norwegian seal-hunting boats. They colonized the island but eventually died out there.

  Svalbard fared no better. Seventeen animals were released by Adventfjorden on West Spitsbergen in 1929. By 1940 the herd numbered 50, but in the 1970s the whole herd disappeared. Releases in Iceland around 1930 also failed.

  In September 1932, polar researcher Adolf Hoel imported 10 muskoxen to Dovrefjell. That herd lasted until World War II, when the animals were hunted and exterminated. New animals were released from 1947 on. In 1971, a small group crossed the national border into Sweden and settled in Härjedalen, founding a Swedish herd.

  The Dovrefjell population is managed over 340 km2 and held about 300 animals in the summer of 2012. It has mostly been growing since 1999, though a measles outbreak in the summer of 2004 killed 29. Some animals die in collisions with trains on the Dovre Railway. The pastures are marginal, with little winter grass, and inbreeding depression is expected in so small a population.

  Russia took a different path. In 1974 and 1975, animals imported from Banks Island and Nunivak were released on the Taymyr Peninsula. Some from Nunivak went to Wrangel Island in 1975. By 2019, Wrangel Island held about 1100 animals, and Taymyr about 11,000-14,000. A few herds even wandered far south to the Putorana Plateau. These populations then supplied further Siberian releases between 1996 and 2010.

  One of the last was in 2010, when six animals were set loose in the Pleistocene Park project area on the Kolyma River. A Russian team led by Sergey Zimov hopes to show that muskoxen and other surviving megafauna vanished from northern Siberia because of human hunting, not climate change.

  Alaska lost its native muskoxen in the late 19th or early 20th century. Excessive hunting is blamed, though a changing climate may have contributed. In 1935, the United States Fish and Wildlife Service released animals onto Nunivak Island to support subsistence living. Later reintroductions followed in places including the Arctic National Wildlife Refuge and Gates of the Arctic National Park.

  In the 1950s, an American researcher and adventurer captured muskox calves in northern Canada and took them to a property he had prepared in Vermont. Canada's government barred him from killing adults defending their young. Nets and ropes failed, so he and his crew herded family groups into open water and separated the calves there. The calves were flown to Montreal and trucked to Vermont, where they adjusted to the milder climate. They grew up, but poor resistance to parasites and disease undermined the effort. The surviving herd was moved to a farm in Palmer, Alaska, where it has done well since the mid-1950s.

  Eastern Canada had a stranger story. Muskox remains have never been found there, though northern Labrador suits the species. In 1967, the Institute for Northern Agricultural Research captured 14 animals near Eureka on Ellesmere Island. It brought them to a farm in northern Quebec, hoping to build a local cottage industry on their fine fiber. The animals thrived, and Inuit knitters were trained. Then it became clear that Quebec's provincial government never wanted domestication. It wanted a wild population to hunt.

  Officials demanded that the institute leave and the farm close. Between 1973 and 1983-54 animals were released at three places in northern Quebec, and the rest went to local zoos. From 1983 to 1986, the released animals grew from 148 to 290, a rate of 25% per year. By 2003, an estimated 1,400 lived in Quebec. In 2005, counters found 112 adults and 25 calves on nearby Diana Island, which they had reached on their own.

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• 8. Wool, Danger and Survival

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  On the 22nd of July 1964, a 73-year-old man was killed by a muskox in Norway, and local authorities later killed the animal. On the 13th of December 2022, a court services officer with the Alaska State Troopers died near Nome, Alaska. He was trying to scare a group of muskoxen away from a dog kennel at his home when one attacked him. Such deaths are extremely rare. Muskoxen are not known to be aggressive, though people who approach them and behave aggressively have occasionally been attacked.

  People also value the animal for what grows on it. Muskoxen are occasionally semi-domesticated for wool, and rarely for meat and milk. Alaska has several muskox farms aimed at harvesting wool. The wool is called qiviut, and it is highly prized for its softness, length and insulation value.

  The species declined historically because of overhunting, but numbers recovered once hunting regulations were enforced. Management in the late 1900s relied mostly on conservative hunting quotas to foster recovery and recolonization. The world population is now estimated at 80,000-125,000, with about 47,000 on Banks Island, Canada.

  Greenland has no major threats to the species, but populations there are often small and scattered. That leaves them vulnerable to local swings in climate. Most live inside national parks, where hunting is barred. In Northeast Greenland National Park the animals are indigenous, and in Kangerlussuaq they are introduced. Muskoxen receive full protection in all four protected areas where they occur.

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