Arctic land mammal
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The muskox (Ovibos moschatus) is a hoofed mammal of the family Bovidae. Native to the Arctic, it is noted for its thick coat and for the strong odor emitted by males during the seasonal rut, from which its name derives. This musky odor has the effect of attracting females during mating season. Its Inuktitut name "umingmak" translates to "the bearded one".
Its Woods Cree names "mâthi-môs" and "mâthi-mostos" translate to "ugly moose" and "ugly bison", respectively. In historic times, muskoxen primarily lived in Greenland and the Canadian Arctic of the Northwest Territories and Nunavut. They were formerly present in Eurasia, with their youngest natural records in the region dating to around 2,700 years ago, with reintroduced populations in the American state of Alaska, the Canadian territory of Yukon, and Siberia, and an introduced population in Norway, part of which emigrated to Sweden, where a small population now lives.
Evolution.
Extant relatives.
The muskox is in the subtribe Ovibovina (or tribe Ovibovini) in the tribe Caprini (or subfamily Caprinae) of the subfamily Antilopinae in the family Bovidae. It is therefore more closely related to sheep and goats than to oxen; it is placed in its own genus, "Ovibos" (Latin: "sheep-ox"). It is one of the two largest extant members of the caprines, along with the similarly sized Takin "Budorcas". While the takin and muskox were once considered possibly closely related, the takin lacks common ovibovine features, such as the muskox's specialized horn morphology, and genetic analysis shows that their lineages actually separated early in caprine evolution. Instead, the muskox's closest living relatives appear to be the gorals of the genus "Naemorhedus", nowadays common in many countries of central and east Asia. The vague similarity between takin and muskox is therefore an example of convergent evolution.
Fossil history and extinct relatives.
The modern muskox is the last member of a line of ovibovines that first evolved in temperate regions of Asia and adapted to a cold tundra environment late in its evolutionary history. Muskox ancestors with sheep-like high-positioned horns (horn cores being mostly over the plane of the frontal bones, rather than below them as in modern muskoxen) first left the temperate forests for the developing grasslands of Central Asia during the Pliocene, expanding into Siberia and the rest of northern Eurasia. Later migration waves of Asian ungulates that included high-horned muskoxen reached Europe and North America during the first half of the Pleistocene. The first well known muskox, the "shrub-ox" "Euceratherium", crossed to North America over an early version of the Bering Land Bridge two million years ago and prospered in the American southwest and Mexico. "Euceratherium" was larger yet more lightly built than modern muskoxen, resembling a giant sheep with massive horns, and preferred hilly grasslands.
A genus with intermediate horns, "Soergelia", inhabited Eurasia in the early Pleistocene, from Spain to Siberia, and crossed to North America during the Irvingtonian (1.8 million years to 240,000 years ago), soon after "Euceratherium". Unlike "Euceratherium", which survived in America until the Pleistocene-Holocene extinction event, "Soergelia" was a lowland dweller which disappeared fairly early, displaced by more advanced ungulates, such as the "giant muskox" "Praeovibos" (literally "before "Ovibos""). The low-horned "Praeovibos" was present in Europe and the Mediterranean 1.5 million years ago, colonized Alaska and the Yukon one million years ago and disappeared half a million years ago. "Praeovibos" was a highly adaptable animal apparently associated with cold tundra (reindeer) and temperate woodland (red deer) faunas alike. During the Mindel glaciation 500,000 years ago, "Praeovibos" was present in the Kolyma river area in eastern Siberia in association with many Ice Age megafauna that would later coexist with "Ovibos", in the Kolyma itself and elsewhere, including wild horses, reindeer, woolly mammoth and stag-moose. It is debated, however, if "Praeovibos" was directly ancestral to "Ovibos", or both genera descended from a common ancestor, since the two occurred together during the middle Pleistocene. Defenders of ancestry from "Praeovibos" have proposed that "Praeovibos" evolved into "Ovibos" in one region during a period of isolation and expanded later, replacing the remaining populations of "Praeovibos".
Two more "Praeovibos"-like genera were named in America in the 19th century, "Bootherium" and "Symbos", which are now identified as the male and female forms of a single, sexually dimorphic species, the "woodland muskox", "Bootherium bombifrons". "Bootherium" inhabited open woodland areas of North America during the late Pleistocene, from Alaska to Texas and maybe even Mexico, but was most common in the Southern United States, while "Ovibos" replaced it in the tundra-steppe to the north, immediately south of the Laurentian ice sheet.
Modern "Ovibos" appeared in Germany almost one million years ago and was common in the region through the Pleistocene. By the Mindel, muskoxen had also reached the British Isles. Both Germany and Britain were just south of the Scandinavian ice sheet and covered in tundra during cold periods, but Pleistocene muskoxen are also rarely recorded in more benign and wooded areas to the south like France and Green Spain, where they coexisted with temperate ungulates like red deer and aurochs. Likewise, the muskox is known to have survived in Britain during warm interglacial periods.
Today's muskoxen are descended from others believed to have migrated from Siberia to North America between 200,000 and 90,000 years ago, having previously occupied Alaska (at the time united to Siberia and isolated periodically from the rest of North America by the union of the Laurentide and Cordilleran Ice Sheets during colder periods) between 250,000 and 150,000 years ago. After migrating south during one of the warmer periods of the Illinoian glaciation, non-Alaskan American muskoxen would be isolated from the rest in the colder periods. The muskox was already present in its current stronghold of Banks Island 34,000 years ago, but the existence of other ice-free areas in the Canadian Arctic Archipelago at the time is disputed.
Along with the bison and the pronghorn, the muskox was one of a few species of Pleistocene megafauna in North America to survive the Pleistocene/Holocene extinction event and live to the present day. The muskox is thought to have been able to survive the last glacial period by finding ice-free areas (refugia) away from prehistoric peoples.
Fossil DNA evidence suggests that muskoxen were not only more geographically widespread during the Pleistocene, but also more genetically diverse. During that time, other populations of muskoxen lived across the Arctic, from the Ural Mountains to Greenland. By contrast, the current genetic makeup of the species is more homogenous. Climate fluctuation may have affected this shift in genetic diversity: research indicates colder periods in Earth's history are correlated with more diversity, and warmer periods with more homogeneity. Muskox populations survived into the Holocene in Siberia, with their youngest records in the region being from the Taymyr Peninsula, dating to around 2,700 years ago (~700 BC).
Physical characteristics.
Both male and female muskoxen have long, curved horns. Muskoxen stand high at withers, with females measuring in length, and the larger males . The small tail, often concealed under a layer of fur, measures only long. Adults, on average, weigh , but can range from . The thick coat and large head suggest a larger animal than the muskox truly is; the bison, to which the muskox is often compared, can weigh up to twice as much. However, heavy zoo-kept specimens have weighed up to . Their coat, a mix of black, gray and brown, includes long guard hairs that almost reach the ground. Rare "white muskoxen" have been spotted in the Queen Maud Gulf Bird Sanctuary. Muskoxen are occasionally semi-domesticated for wool, and rarely for meat and milk. The U.S. state of Alaska has several muskoxen farms specifically aimed at wool harvesting. The wool, called "qiviut", is highly prized for its softness, length, and insulation value. Prices for yarn range between .
A muskox can reach speeds of up to . Their life expectancy is between 12 and 20 years.
Range.
Prehistory.
During the Pleistocene period, muskoxen were much more widespread. Fossil evidence shows that they lived across the Siberian and North American Arctic, from the Urals to Greenland. The ancestors of today's muskoxen came across the Bering Land Bridge to North America between 200,000 and 90,000 years ago. During the Wisconsinan, modern muskox thrived in the tundra south of the Laurentide Ice Sheet, in what is now the Midwest, the Appalachians and Virginia, while distant relatives "Bootherium" and "Euceratherium" lived in the forests of the Southern United States and the western shrubland, respectively. Though they were always less common than other Ice Age megafauna, muskox abundance peaked during the Würm II glaciation 20,000 years ago and declined afterwards, especially during the Pleistocene/Holocene extinction event, where its range was greatly reduced and only the populations in North America survived. The last known muskox population in Europe died out in Sweden 9,000 years ago. In Asia, muskox persisted until just 615-555 BCE in Tumat, Sakha Republic.
Following the disappearance of the Laurentide Ice Sheet, the muskox gradually moved north across the Canadian Arctic Archipelago, arriving in Greenland from Ellesmere Island at about 350 AD, during the late Holocene. Their arrival in northwestern Greenland probably occurred within a few hundred years of the arrival of the Dorset and Thule cultures in the present-day Qaanaaq area. Human predation around Qaanaaq may have restricted muskoxen from moving down the west coast, and instead kept them confined to the northeastern fringes of the island.
Recent native range in North America.
In modern times, muskoxen were restricted to the Arctic areas of Northern Canada, Greenland, and Alaska. The Alaskan population was wiped out in the late 19th or early 20th century. Their depletion has been attributed to excessive hunting, but an adverse change in climate may have contributed. However, muskoxen have since been reintroduced to Alaska. The United States Fish and Wildlife Service introduced the muskox onto Nunivak Island in 1935 to support subsistence living. Other reintroduced populations are in Arctic National Wildlife Refuge, Bering Land Bridge National Preserve, Yukon's Ivvavik National Park, a wildlife conservation center in Anchorage, Aulavik National Park in Northwest Territories, Kanuti National Wildlife Refuge, Gates of the Arctic National Park, and Whitehorse, Yukon's wildlife preserve.
There have been at least two domestication endeavours. In the 1950s, an American researcher and adventurer was able to capture muskox calves in Northern Canada for relocation to a property he prepared in Vermont. One condition imposed by the Canadian government was that he was not allowed to kill adults defending their young. When nets and ropes proved useless, he and his crew herded family groups into open water, where calves were successfully separated from the adults. Once airfreighted to Montreal and trucked to Vermont, the young animals habituated to the temperate conditions. Although the calves thrived and grew to adulthood, parasite and disease resistance problems impaired the overall success of the effort. The surviving herd was eventually moved to a farm in Palmer, Alaska, where it has been successful since the mid-1950s.
Reintroductions in Eurasia.
In 1913, workers building a railway over Dovrefjell found two fossil muskox vertebrae. This led to the idea of introducing muskoxen to Norway from Greenland. The first release in the world was made on Gurskøy outside Ålesund in 1925–26. They were muskoxen caught by Norwegian seal-hunting boats in Greenland. The animals colonized the island, but eventually died out there. An attempt to introduce the muskox to Svalbard also failed. Seventeen animals were released in 1929 by Adventfjorden on West Spitsbergen. In 1940, the herd numbered 50, but in the 1970s, the whole herd disappeared. In September 1932, polar researcher Adolf Hoel conducted another experiment, importing 10 muskoxen to Dovrefjell. This herd survived until World War II, when they were hunted and exterminated. In 1947 and later, new animals were released. A small group of muskoxen from Dovrefjell migrated across the national border to Sweden in 1971 and established themselves in Härjedalen, whereby a Swedish herd was established.
The Norwegian population on Dovrefjell is managed over an area of and in the summer of 2012 consisted of approximately 300 animals. Since 1999, the population has mostly been increasing, but it suffered a measles outbreak in the summer of 2004 that killed 29. Some animals are also occasionally killed as a result of train collisions on the Dovre Railway. The population is divided into flocks in the Nystuguhø area, Kolla area and Hjerkinn. In the summer they move down towards Driva, where there are lush grass pastures.
Although the