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Ovibos moschatusmuskox

By Sarah Marie Elder

Geographic Range

Ovibos moschatus is a circumpolar species native to Canada, Greenland, and up until the late 1800's, Alaska. The species was reintroduced to Alaska from animals captured in Greenland in the 1930's. Muskox have also been introduced into Russia, Svalbard, Norway, and Siberia. Some herds have also found their own way from Norway into Sweden. ("Muskox (Ovibos moschatus)", 1995; Groves, 1997)

Habitat

Ovibos moschatus lives north of the tree line on the arctic tundra. Summers have a very short growing seasons of three to four months with lush and abundant vegetation. Winters are long and very cold with little precipitation and harsh winds. There is little vegetation in winter and shallow snow. ("Muskox (Ovibos moschatus)", 1995; Gray, 1990; Groves, 1997; Woodward, 1997)

Physical Description

Many of the physical characteristics of O. moschatus can be attributed to arctic adaptations. Musk oxen have barrel-shaped bodies with short legs, and their entire bodies are covered with fur except for the small area between the nostrils and lips. Both sexes have cream-colored horns with black tips that grow together at the center of the head, drop down along side of head, then curve up to form sharp hooks. These horns grow with age. The tail is short (5 to 10 cm) and is entirely covered and hidden under the fur. Fur can be divided into two types: guard hair and qiviut (pronouced kiv-ee-Ute). Guard hairs are the continuously growing dark hairs that create the characteristic long, shaggy coat. This portion of the pelage can grow long enough to brush the ground on older muskoxen. This long hair is sometimes refered to as a skirt. The guard hairs act as protection against wind and precipitation, as well as insects. Qiviut is the insulating winter coat of muskoxen. It begins growing in the fall and is shed out through the guard hair in the spring. The back is marked by a lighter colored patch of brown or cream where the guard hairs are shorter. This is refered to as the saddle. Legs of these animals are white. Older adult muskoxen sometimes develop a large mane of fur that sits on the shoulders. (Gray, 1990; Groves, 1997; Rowell, 1990)

Subspecies include barren ground muskoxen, Ovibos moschatus moschatus, which are native to Canada and were native to Alaska until extirpation in the late 1800's. White-faced muskoxen, Ovibos moschatus wardi, are native to Greenland and have been introduced to many locations. Ovibos moschatus wardi tends to be slightly smaller than O. moschatus moschatus, but distinction between the two is based mostly on location of the animal. The two subspecies can interbreed. (Gray, 1990; Groves, 1997)

Calves are born in the early spring with very short guard hair and nubs where the horns will begin growing soon after. They are also born with a layer of baby qiviut and over the harsh winter are dependent on the cows for both additional body warmth and protection from the elements by standing in the skirt. (Groves, 1997)

Female weight ranges from 180 to 275 kg, with an average of 250 kg. Head and body length can vary from 135 to 200 cm. Muskoxen typically stand 120 cm at the shoulders. Females grow horns, but lack the extra thickness of a horn boss at the base of the horns. Hook size typically matches that of males. Ovibos moschatus has an udder with four teats, also covered in fur. (Gray, 1990; Groves, 1997; Rowell, 1990)

Males typically weigh an average of 320 kg, with a range of 300 to 400 kg. The combined head and body length varies from 200 to 250 cm. Males have a large horn boss, which is an extra thickness of the base of their horns at the top of the skull, that is between 15 and 20 cm thick. This feature protects them during mating behaviors that include headbutting. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Range mass
    180 to 400 kg
    396.48 to 881.06 lb
  • Average mass
    285 kg
    627.75 lb
  • Range length
    150 to 260 cm
    59.06 to 102.36 in
  • Average length
    210 cm
    82.68 in

Reproduction

Ovibos moschatus is considered a harem breeder in which one dominant male attempts to mate with all of the estrus females of the herd. Beginning in late summer and into fall, males compete for dominance using very ritualized behaviors. Males attempt to intimidate each other through posturing, roaring, head swinging, urinating on forefeet with strong scent markers, displaying broadsides to show size, and headbutting. During headbutting, males face each other up to 45 meters apart, then charge up to 20 or 25 miles per hour and crash together on the horn bosses. They can repeat this procedure up to 10 or 12 times or until one of the males cannot continue or runs away. This behavior is rarely fatal. Males that compete for dominance are typically between the ages of 6 and 8 years old. Older bulls are usually not strong enough, and younger males are typically not large enough, to compete. Competition between bulls sometimes results in solitary males. Once dominance is determined, a bull attempts to keep the females close together to defend them from other males. Dominant males may breed multiple times with each female during one season. Young muskoxen and non-dominant bulls typically keep their distance from the breeding harem. (Gray, 1990; Groves, 1997; Rowell, 1990)

Ovibos moschatus breeds from late August into September and gives birth between mid-April and mid-May. Muskoxen usually have single offspring after a gestation of about 8 months. Twins are very rare and do not usually survive. Generally within 45 minutes of birth, calves are standing and nursing. Calves typically weigh 9 to 11 kg at birth and can gain up to 0.5 kg a day. Though calves are born with a layer of baby qiviut and brown fat, they are dependent upon their mothers for warmth and food for the first winter of their lives, sometimes longer. Calves start eating adult food within weeks of birth, although they continue to nurse for 10 months to 1 year, sometimes longer depending on food availability, birth of a new calf, or temperament of the cow. Muskox calves follow their mothers and hide underneath the mother's skirt of guard hair.

Females typically reach sexual maturity between 1 to 4 years of age, depending on body condition, and will calve alternate years. Calving every year is possible if food sources are available. Males typically reach sexual maturity between 3 and 4 years. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Breeding interval
    Female muskoxen breed once a year or once every two years, depending upon the availability of food.
  • Breeding season
    Breeding occurs during late August and into September.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    7.5 to 8.5 months
  • Range weaning age
    8 to 24 months
  • Average weaning age
    10-14 months
  • Range time to independence
    8 to 24 months
  • Average time to independence
    10-14 months
  • Range age at sexual or reproductive maturity (female)
    1.5 to 4 years
  • Average age at sexual or reproductive maturity (female)
    2-3 years
  • Range age at sexual or reproductive maturity (male)
    2 to 4 years
  • Average age at sexual or reproductive maturity (male)
    3-4 years

Although they are fully furred and able to stand from birth, calves are dependent upon their mothers for milk, warmth from their bodies and fur, and protection. Though calves can generally eat adult food within weeks of birth, to gain sufficient body weight to survive through the winter they require milk from their mothers. For warmth, calves often lie with their mother, or stand underneath her skirt next to her belly. During attack from predators, the calves are often pushed behind the rumps of the adults, or into the middle of a circle formation. Mothers also teach calves the social hierarchy behaviors by playing "games" such as king of the mountain, and mock headbutting.

Males are not reported to directly care for the young. However, since these animals are social, it is likely that the adult male in a herd helps to protect the young in the herd. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • male
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan/Longevity

Ovibos moschatus lives in very harsh climates and harsh winters may cause death for young calves as well as older adults. Females typically live 15 to 18 years though some older than 20 years have been recorded in the wild and in captivity. Males typically only live 10 to 12 years, as the breeding season is very strenuous. Adult muskoxen typically die through the inability to properly digest food because of excessive wear on molar teeth, or as a result of predation. ("Muskox (Ovibos moschatus)", 1995; Gray, 1990; Groves, 1997; Rowell, 1990)

  • Range lifespan
    Status: wild
    >20 (high) years
  • Average lifespan
    Status: wild
    14 years
  • Range lifespan
    Status: captivity
    >20 (high) years
  • Average lifespan
    Status: captivity
    14 years
  • Typical lifespan
    Status: wild
    <1 to 18 years
  • Average lifespan
    Status: wild
    14 years
  • Typical lifespan
    Status: captivity
    10 to 18 years

Behavior

Ovibos moschatus is a social species and much of the behavior is based on the harem breeding system. Muskoxen live in herds as small as 5 animals during the summer, and may join with other small groups to form herds as large as 60 individuals in the winter. These larger groups help provide for protection from both the elements and predators. Other advantages of such a large herd size are that during the long winters, it is easier for a lost muskox to locate a large heard in the dark than a few individuals. Also, younger animals may have the advantage of grazing more food supplies that have been uncovered under the snow. Most herds average between 10 and 20 animals. ("Muskox (Ovibos moschatus)", 1995; Gray, 1990; Groves, 1997; Rowell, 1990)

Muskoxen have many arctic adaptations to the cold (such as short legs, thick fur, and high body fat), that limit their mobility. Though muskoxen can run as fast as 25 miles per hour, they can easily overheat. For this reason, O. moschatus is generally slow moving and has very short migrations within the home range. However, under certain conditions (weather permitting), muskoxen calves as well as adults will play. This play can include chasing and king of the mountain. (Gray, 1990; Groves, 1997; Reynolds, et al., 2001; Rowell, 1990)

The social hierarchy in the herd is based upon dominance. Dominance among males is typically determined during the breeding season, and sometimes throughout the year through headbutting and chasing, as well as grunting and bellows. Sometimes males are forced out of the herds during the breeding season. Among females, dominance is determined by age and size, with the larger, older females typically exerting dominance over younger, smaller, females through pushing, shoving, and chasing. Calves are generally lowest in the hierarchy, although they determine dominance amongst themselves through chasing, mounting, and play. Generally, the higher the dominance status of the muskox, the better its food supply and breeding rights. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Range territory size
    23 to 223 km^2
  • Average territory size
    70 km^2

Home Range

Home ranges for muskoxen in Alaska are reported to be very large in the summer, averaging 223 square kilometers, and much smaller in the winter and calving seasons, ranging from 27 to 70 square kilometers. Muskoxen will typically stay in areas near water during summer months and then move to higher ground areas where wind will blow off much of the snow covering food supplies during the winter. (Reynolds, et al., 2001)

Communication and Perception

Ovibos moschatus has very interesting vocal abilities. Calves, when communicating with cows or each other, bleat. The pitch of the bleat lowers with maturity. Adults have deeper voices that sound closer to roars and rumbles that can be heard long distances. Adults also grunt and snort at each other, at calves, and at other animals. Pushing and shoving, as well as chasing and stomping, are used to communicate dominance. (Gray, 1990; Groves, 1997; Rowell, 1990)

Much of the non-vocal communication among muskoxen occurs during the breeding season when males compete for dominance and breeding rights. Males have very strong-smelling urine and urinate on their front legs and dribble urine during displays as warnings to competitors. They will also use a gland near each eye to mark objects by rubbing their faces against the item to be marked. Bulls also swing their heads, walk sideways, and horn the ground to gather chunks of earth to make themselves look larger. (Gray, 1990; Groves, 1997; Rowell, 1990)

Food Habits

Muskoxen are generalized grazers. As calves, they are dependent upon the milk of their mothers for up to 1 year. Within weeks of birth, they begin incorporating the adult foods into their diet. In the summer months, the diet inculdes grasses, leafy plants, sedges, mosses, shrubs, herbs, and generally any vegetation available. The fecal matter of the animals at this time is very moist and still has high levels of nutrients available. In the winter months, the diet of muskoxen changes to willow, dwarf birch stems, roots, mosses, lichen, and any vegetation they can locate under or above the snow. The fecal matter during these months is very dry and has very few nutrients left after the animals have digested the food. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit
  • flowers
  • bryophytes
  • lichens
  • Other Foods
  • fungus

Predation

The known predators of O. moschatus are polar bears, brown bears, and wolves. When faced with a predator coming head on, muskoxen line up with their heads down and horns facing the attacker. The calves are generally located behind the adults. When attacked by multiple predators, the herd creates a circle with horns pointed out and calves in the center of the herd. Larger adults may charge out to attack a predator. When a predator approaches the herd, the muskoxen attempt to headbutt or hook that predator with their horns. Muskoxen have been known to throw and trample wolves. As O. moschatus is adapted to arctic life, these animals can overheat easily and cannot run faster than wolves or bears long enough to escape from them. They therefore tend to stay in the circle formation as long as possible. (Gray, 1990; Groves, 1997; Rowell, 1990)

Ecosystem Roles

Ovibos moschatus is herbivorous, and consumes plant life. It also provides a food source for arctic scavengers, wolves, polar bears, and brown bears. Muskoxen may help to disperse seeds as they graze. (Gray, 1990; Groves, 1997; Rowell, 1990)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

One of the arctic adaptations of muskoxen is the winter coat of underwool, called qiviut (pronounced "kiv-ee-Ute"). Qiviut is an Alaskan native word that has adapted many spellings. The wool is finer than cashmere and eight times warmer than wool. When collected from the few domestic muskox herds, it can be bought by companies or individuals to make garments, and can be sold raw. The rarity of the fiber and the garments makes it very valuable. Managers of 'domesticated' herds supply qiviut to companies and co-operations for use in making garments. A main producer of these garments is the Musk Ox Producer's Co-Operative. ("Oomingmak: Musk Ox Producer's Co-operative", 1996; Chambers, 1993)

Research is also performed at the Large Animal Research Station at the University of Alaska Fairbanks on nutrition and arctic adaptations which can be applied to wildlife conservation, biology, and many other aspects. LARS has a captive herd of approximately 40 muskoxen. (Groves, 1997)

In some areas, including Alaska, current laws allow hunting if the hunter is selected through a periodic lottery system, though laws vary across locations and countries. There are domestic herds of muskoxen that can be used for meat, though the qiviut of the animal is much more valuable and continually produced. (Groves, 1997)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

There are no known adverse affects of O. moschatus on humans.

Conservation Status

Though herds of O. moschatus native to Alaska and parts of Europe were driven to extinction through hunting pressures and climate fluctuations in the late 1800's, the species has been successfully reintroduced from suviving populations in Canada and Greenland and is doing well, currently numbering greater than 60,000 world wide. Ovibos moschatus is currently not listed as a threatened species. (Gray, 1990; Groves, 1997; Reynolds, et al., 2001; Rowell, 1990)

Other Comments

Muskoxen actually have no musky smell. During the breeding season, the urine the males spray on themselves and the ground is rather pungent, but O. moschatus lacks a true musk gland. Also, it wasn't until recent genetic studies that it was discovered that the closest relatives to muskoxen are members of the Caprinae subfamily. It was previously suggested, based on appearance, that its closest members were cows, bison, or buffalo. (Groves, 1997; Rowell, 1990)

Contributors

Sarah Marie Elder (author), University of Alaska Fairbanks, Link E. Olson (editor, instructor), University of Alaska Fairbanks.

Nancy Shefferly (editor), Animal Diversity Web.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

polar

the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.

polygynous

having more than one female as a mate at one time

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tundra

A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

1995. "Muskox (Ovibos moschatus)" (On-line). Wildlife Species Information: U.S. Fish and Wildlife Service. Accessed November 18, 2004 at http://species.fws.gov/species_accounts/bio_musk.html.

Applied Microsystems, Inc. 1996. "Oomingmak: Musk Ox Producer's Co-operative" (On-line). Accessed November 18, 2004 at http://www.qiviut.com/store/index.cfm?target=home&CFID=341026&CFTOKEN=87725359.

Chambers, W. 1993. Qiviuq. Spin Off, Summer: 48-55.

Gray, D. 1990. Muskox Biology. Pp. 23-48 in B Holst, ed. International Studbook for Muskox: Ovibos moschatus .

Groves, P. 1997. Muskox. Alaska Geographic, 23/4: 56-86.

Reynolds, P., K. Wilson, D. Klein. 2001. "Arctic Refuge Coastal Plain Terrestrial Wildlife Research Summaries" (On-line). Accessed November 18, 2004 at http://www.absc.usgs.gov/1002/section7part1.htm.

Rowell, J. 1990. The Muskox. Pp. 2-22 in B Holst, ed. International Studbook for Muskox: Ovibos moschatus .

Woodward, S. 1997. "The Tundra" (On-line). Major Biomes of the World. Accessed November 12, 2004 at http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/tundra/tundra.html.

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