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Ovis ammonargali

By John Tonda

Geographic Range

Argali sheep are found in mountainous areas in central Asia above 1000 m. This species has a wide range with several localized subspecies recognized. The range of the argali sheep covers the Irtysh River and Altrai Mountains in Siberia, south to the Himalayas in Tibet. It stretches to cover the land west to the Oxus river near Afghanistan, and eastward to the Mongolian plateau. (Clark, 1970)

Habitat

Argali sheep usually occupy the same areas for the duration of their lives. They are found at upper elevations on steep slopes above 1000 m. Adult males are larger and faster than females, and do not have as great a need to avoid predators. They therefore choose prime vegetative habits that are more exposed than are those chosen by females and young rams. During summertime as food becomes available, higher elevations are chosen by all animals.

The landscape of central Asia is vast and mostly open. Mountains have been worn down by erosion and huge sloping hills remain, allowing a great range of visibility for the animals which live there. Vegetation is dominated by grasses, with very few trees present on the landscape. (Clark, 1970; Geist, 1991)

  • Range elevation
    1000 to 6000 m
    3280.84 to 19685.04 ft
  • Average elevation
    3000 m
    9842.52 ft

Physical Description

Ovis ammon is the largest of the world’s sheep, weighing in between 60 and 185 kg. Shoulder height is between 90 and 125 cm. Horns are a prominent feature on these animals. They have a corkscrew shape with rounded combat edges. Males and females both have horns, although the horns of females are smaller. The male’s horns can be up to 190 cm in length, measured along the coil.

The coloration of the argali sheep is two-toned with a dark band running laterally along the belly, separating the dark brown upper half from the pale hair below. Argali sheep have a distinct, light rump patch and pale face. Males generally have a light colored neck. The coat is shed twice yearly, with the summer coat being darker and the winter coat having a longer hair length. (Clark, 1970; Geist, 1991)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • ornamentation
  • Range mass
    60 to 185 kg
    132.16 to 407.49 lb
  • Average mass
    160 kg
    352.42 lb
  • Range length
    120 to 190 cm
    47.24 to 74.80 in
  • Average length
    180 cm
    70.87 in

Development

During the first 4 months before weaning, young lambs rapidly put on body weight and increase in size. Muscle tone and coordination are further developed during nursing. Until about age two social skills are learned. A one year old could mate physiologically but does not have necessary social skills. Social skills are important since sheep are very social animals and spend their entire lives in groups. By age 5 an Argali sheep is fully mature. A sheep lives on average for about 10 years with some rams living up to 20 years.

(Nowak 1995)

Reproduction

Mating is polygynandrous; numerous matings can occur in a season between many partners. A dominant male will mate with numerous females and will herd harems during the rut. Females will mate with numerous males if the opportunity arises. Such an opportunity may arise when the dominance among males changes or when a female leaves a herd to join another group. (Geist, 1991; Nowak, 1995)

Reproductive habits of the world’s largest sheep can be quite extreme. Huge rams weighing 180 kg run head first into each other while in rut. They smash their horns together in intense combat designed to determine dominance relationshipes between males. Dominant males then mate with mature females in estrous.

Females are sexually mature at 2 years of age and males by 5 years. This differnce makes sense, because the males must grow so much larger than the females before they can breed.

The rut occurs in autumn and early winter, ensuring that lambs are born in the late spring. Females are fertile about every three weeks in the fall until they are impregnated.

Gestation lasts for 150 to 180 days. Females give birth to one or two lambs. Females separate from the herd to give birth and remain separated for a few days. During this time, the lamb lays motionless while the mother grazes. Lambs are precocial at birth, and can stand. Still, gaining body mass quickly is essential for survival.

A ewe can reproduce in her first year, although the majority of females wait for their second year. Females can produce young successfully for up to eight years.

After a lamb is a few months old, the relationship between mother and lamb ends. Lambs are wenaed around four months of age. Lambs usually form their own social groups. (Huffman, 2003; Nowak, 1995)

  • Breeding interval
    These sheep breed once per year.
  • Breeding season
    Mating occurs in the autumn and early winter.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    5.17 to 5.33 months
  • Average gestation period
    8.5 months
  • Range weaning age
    4 to 5 months
  • Average weaning age
    4 months
  • Average time to independence
    5 months
  • Range age at sexual or reproductive maturity (female)
    1 to 2 years
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (male)
    5 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    823 days
    AnAge

Mothers care for young for about 4 months before weaning. Young sheep nurse before weaning, receiving milk high in fat protein and antibodies to help add body mass and sustain health and vitality. During nursing, young lambs also receive bacteria needed for ruminant digestion.

Males do not participate in care of the young. (Nowak, 1995)

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
  • extended period of juvenile learning

Lifespan/Longevity

The lifespan of Argali sheep is on average 10 to 13 years. Predators and extreme climatic conditions kill older sheep, so maximum lifespan is seldom achieved. Males can generally live longer than females. (Nowak, 1995)

  • Range lifespan
    Status: wild
    1 to 20 years
  • Average lifespan
    Status: wild
    10-13 years
  • Typical lifespan
    Status: wild
    7 to 11 years
  • Average lifespan
    Status: wild
    10 years

Behavior

Argali sheep are herding animals, and are usually found in groups of 2 to 100 animals. Herds are segregated by sex except during the breeding season.

Sheep are very calm and non aggressive towards other sheep, and are very social animals. Members of a herd will follow one another, and an individual sheep will often seek contact with other sheep.

A strategy of safety in numbers is common of all the worlds’ sheep. It is thought that a sheep may help to protect itself from predation by being close to another sheep, who might fall victim to an attack instead.

Lambs play a great deal, learning behaviors necessary for survival, such as mating rituals, how to escape from predators, and how to be agile on the steep terrain found in their normal habiat.

The horns of these sheep are a conspicuous feature on the males. During the rut, adult males run headfirst into each other’s horns, but seldom suffer serious injury. (Although such crashes probably give them terrible headaches!) Argali sheep seldom use their horns to defend themselves from predators. Insetead, they use avoidance and rapid flight from predators as their main strategies to avoid being eaten.

When spooked, a solitary sheep may remain motionless until the threat disappears. This is very different from the behavior of these sheep in a herd-- when alarm will cause them to run and jump away. (Clark, 1970)

Home Range

The home range of these animals has not been reported.

Communication and Perception

These sheep communicate with hissing through the nostrils or grunts from the throat. Communication is important for mother and young and is based on visual, oral and scent confirmations. Also, communication through scent glands is not well understood but thought to be important for sexual signaling. Males can smell females that are fertile and ready to mate. Distinctive pelage can be a lon-sidtance visual signal to other sheep of where other herds are. This information can be used by the sheep when deciding to avoid or join other groups. (Huffman, 2003)

Food Habits

The landscape inhabited by these sheep is free of trees, but plentiful in food easily and efficiently digested. Argali sheep are herbivorous and feed on grasses, herbs, and sedges. Females and young rams feed in higher altitude terrain with diminished food quality. These feeding locations provide easy escape protection from predators. Adult males feed in lower terrain with higher food quality and use fast, sustained running to evade predators.

Argali sheep are grazers that have adapted to survive in an arid, windy and extreme climate of their high altitude home. (Geist, 1991)

  • Plant Foods
  • leaves
  • seeds, grains, and nuts

Predation

Argali sheep stay in areas inaccessible to predators, such as high on hills or on steep embankments with good viewpoints.

Due to their large size, Argali sheep are poor jumpers and do not usually jump as an escape techniwque, although this is a more common practice in the smaller females and young animals. Powerful long legs help these sheep run over all types of terrain.

To avoid predation all animals in a herd move together and stay with group. If an Argali sheep is alone, it will sometimes remain motionless in the hope of being overlooked by a predator. Using the horns for defense is very uncommon.

Predators of Argali sheep are wolves, snow leopards, and leopards. They have also been heavily hunted by humans. (Clark, 1970)

Ecosystem Roles

Argali sheep play a role in plant succesion, because their feeding habits allow grasses to flourish over sedges. This species is also a very important prey item for endangered snow leopard populations. (Clark, 1970)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

O. ammon benefits humans by providing meat and hair for native subsistence hunters. The clothing made from this animal's hair, as well as the food it provides, can be essential for survival.

Sport hunters enjoy trophy killing the world’s largest sheep. The lure of largest sheep has become a goal for many hunters willing to pay any cost for such a trophy. Revenue is raised on tourism and expedition costs, helping local peoples by providing an important source of currency.

In recent years ecotourism has increased, bringing even more financial gains to the region. (Clark, 1970; Huffman, 2003; Nowak, 1995)

Economic Importance for Humans: Negative

O. ammon negatively affects humans by competing with livestock for grazing lands. But mostly Argali sheep are in remote areas not used by domestic livestock. It is more likely that the domestic sheep raised by humans have negatively affecte Argali sheep, pushing them into more remote, lower quality habitats. (Nowak, 1995)

Conservation Status

The IUCN classifies the entire species O. ammon as vulnerable. Sport hunting has been damaging to the species, with the lure of attaining a trophy from the world’s largest sheep. Since the nineteenth century, hunting has removed this species from some of its former range. O. ammon longer present in northeastern China, southern Siberia and parts of Mongolia.

Overall numbers of individuals and dispersal have declined. Recent problems for this species include habitat loss due to competition with domestic livestock and humans encroaching.

It is interesting to note that the threats to O. ammon can also be threats to the populations of their predators, such as snow leopards, which depend greatly on a stable supply of these sheep for their own diet. (Clark, 1970; Nowak, 1995)

Other Comments

O. ammon is classified into seven subspecies: nigrimontana, hodsoni, jubata, darwini, ammon, polii and karelin. Some taxonomists also recognize the subspecies musimon, the European mouflon, although others see this as a distinct species.

Subspecies are distinguished by seasonal age related pelage differences, body size and geographic location.

Argali sheep have reduced in numbers over the past two hundred years and populations of all subspecies are on the decline. Greater habitat protection of Argali sheep is needed, with reduced hunting of trophy males, to protect this vulnerable species. (Geist, 1991; Nowak, 1995)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

John Tonda (author), Humboldt State University, Brian Arbogast (editor), Humboldt State University.

Glossary

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.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

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.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

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

nomadic

generally wanders from place to place, usually within a well-defined range.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

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.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

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.

References

Clark, J. 1970. The Great Arc Of The Wild Sheep. Norman: University of Oklahoma Press.

Geist, V. 1991. On the taxonomy of giant sheep (Ovis ammon Linnaeus, 1766). Canadian Journal of Zoology, 69: 706-723.

Huffman, B. 2003. "Argali Sheep" (On-line). Ultimate Ungulate Page. Accessed December 16, 2003 at http://www.ultimateungulate.com/Artiodactyla/Ovis_ammon.html.

Nowak, R. 1995. "ARTIODACTYLA; BOVIDAE; OVIS; Sheep" (On-line). Walkers Mammals of the World Online. Accessed December 16, 2003 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/artiodactyla/artiodactyla.bovidae.ovis.htm.

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