Argali - Life History

Life History

Argalis live in herds typically numbering between 2 and 150 animals, segregated by sex, except during breeding season. Most populations show large numbers of adult females, comprising more than half of a local population, against around 20% being comprised by adult males and a further 20% by young argali. Some rams are solitary but most are seen in small herds numbering between 3 and 30 individuals. Females and their young live in larger groups, regularly up to 92 individuals and exceptionally to 200 animals. Migrating herds, especially males, have been reported. Most migration appear to be related to seasonally decreased food sources, though an overabundance of biting insects (especially gadflies), severe drout or fires, poaching by humans and large numbers of domestic livestock may also trigger movements. With their long legs, herds can travel quickly from place to place. Argalis tend to live at higher elevations during the summer.

Argali reach breeding maturity at 2 to 3 years of age. Rutting may occur from October to mid-January, generally lasting longer in lower elevations. In rutting herds, both rams and ewes attack others of their own sex, exerting dominance by ramming each other with their horns. Although such groups engage in lamb-like play, the combat of a pair of mature males is a serious business. The rams slam into each other, with their forelegs up in the air, exerting enough force to be heard up to 800 m (2,600 ft) away. Often the older males (over 6 years of age), which are also often the largest, end up the dominant ones and younger males are chased off once the ewes are in estrus. Once dominance is established, the top rams begin approaching ewes and smell their urine to determine their receptiveness. The ram then repeatedly approaches the ewe and forceably mounts her. Mating commences around 2 to 3 weeks after the rutting begins. Rams may remain in the company of ewes for up to 1 to 2 months after the rutting period is complete.

The gestation period lasts a little over 160 days. Births occur in late March or April, with a variable number of females being barren. Most subspecies give birth to a single lamb, though in some races twins are not uncommon and even as many as 5 have been born at once. At birth, the lambs weigh 2.7–4.6 kg (6.0–10 lb). The newborn lamb and mother ewe stay around where the birth occurs overnight and, on the next day, both usually walk together. Lambs often play in groups, jumping up and down together, sometimes being joined by their mothers. Weight gain is often quite fast and the lambs may weigh 10 times their birth weight by their first birthday. Females often attain their maximum mass by 2 years of age, but males appear to continue to grow larger and heavier in their 3rd and 4th years. Milking teeth develop around 3 months of age, with a full set of teeth developing by around 6 months. By the time their teeth develop, lambs are capable grazers and the ewes spot nursing them anywhere from August to May of the following year. Most argali live 5–10 years, but are capable of living to 13 years in the wild.

Adult argalis eat 16–19 kg (35–42 lb) of food a day. The vegetation preferred by the species varies based on elevation and area. In higher elevations, they predominantly eat cereals, sedges and forbs. At mid-elevation habitats, they more regularly feed on bushes and mesophyte grasses. In the lowest ranges and the spurs of deserts, Argalis cereals and sedges again predominant but often of different species than the high elevation ones. In north-central Kazakhstan, sprouts, leaves, flowers and fruits are significant to the diet all year, whereas they appear to be a rare dietary supplement over the rest of the range. Water is needed by argalis, which is rarely a problem for specimens living in high elevation, where melting snow and small waterways are regularly encountered. In drier climes, argali may travel several kilometers in search of water. When available, argali readily consume saline soil.

Although they are locally sympatric with Siberian ibex, the two species have differing habitat and pasture preferences, reducing likely competition. In Tibet, the argali must regularly compete with other grazing species for pasture, including Tibetan antelope, Bharal, Thorold's deer and Wild yaks. Competition is most serious with livestock, especially domestic yak and domestic sheep, with which Argali are frequently forced to intermingle and often catch diseases and parasites from. The main predator of argali are gray wolves, which often exploit harsh winter conditions (such as deep snow) in order to capture the wild sheep, though can and do take specimens of any age or condition year around. Where not locally expirated, snow leopards and leopards are also predators of argali of any age. Eurasian lynx and wolverines may seldomly kill argali to at least the size of winter-weakened ewes. Red foxes and domestic dogs (largely those kept by sheep-herders) will predate lambs. Cinereous vultures, lammergeiers and golden eagles have been observed circling herds of ewes with lambs in a possibly predacious manner and remains of argali lambs have been observed at golden eagle nests. Smaller predators, such as raptorial birds and smaller mammalian carnivores, are attacked by mother ewes but, in the presence of larger predators, the ewes quickly run away with the lambs following them.