The Siberian ibex (Capra sibirica), also known using regionalized names including Altai ibex, Asian ibex, Central Asian ibex, Gobi ibex, Himalayan ibex, Mongolian ibex or Tian Shan ibex, is a polytypic species of ibex, a wild relative of goats and sheep. It lives in Central Asia, and is, by far, the most widely-distributed species in the genus Capra. In terms of population stability, Siberian ibex are currently ranked as Near Threatened, mostly due to over-hunting (mainly by wealthy, foreign hunters), low densities (in most areas) and overall decline; still, reliable data is minimal and difficult to come by, in addition to the animals’ expansive natural range, so accurate observations are still scant. The Siberian ibex has, formerly, been treated as a subspecies of the Eurasian Alpine ibex, and whether or not it is a single species or a complex of distinct units that stand out as genetically-distinct (at species level) is still not entirely clear. The Siberian ibex is the longest and heaviest member of the genus Capra, though its shoulder height is slightly surpassed by the markhor.
Appearance
Siberian ibexes are large and heavily built goats, although individual sizes vary greatly. Males are between in shoulder height, and weigh between . Females are noticeably smaller, with heights between , and weights between . The nose is straight in profile, the neck short, and the back straight. The neck is also particularly thick and muscular in males, but much less so in females. Both sexes have beards, although the male's beard is more pronounced, and those of females are sometimes absent altogether. Both sexes also possess a large scent gland, about across, beneath the tail.
The female's horns are relatively small, and grey-brown in colour, measuring an average of long. Those of fully-grown males are black and typically measure about , although in extreme cases they can grow to . Both sexes have circular rings around their horns that represent annual growth, but males also have large transverse ridges along the front surface. The exact shape of the horns varies considerably between individuals.
The colouration is also variable, from dark brown to light tan, with some reddish individuals. There is usually a stripe of darker hair down the centre of the back and onto the tail, and some males have saddle-like patches on the back in the winter. The undersides are paler, and, in the winter, mature males becoming much darker with white patches. Females and infants are generally more bland in colour than the adult males, and do not always have the stripe down the back. Siberian ibexes typically moult between April and July, developing their paler summer coat, which continues to grow and become darker as the year progresses, reaching the full winter condition around December.
Subspecies
Though some recent authorities treat the species as monotypic, others have recognized four subspecies, based mainly on differences in total size, size of horns and colour of pelage:
C. s. sibirica (Siberian or Altai Ibex) – Sayan Mountains
C. s. alaiana (Tian Shan Ibex) – Alay Mountains
C. s. hagenbecki (Gobi or Mongolian Ibex) – western Mongolia
C. s. sakeen (Himalayan Ibex – Pamir Mountains, western Himalayas, India, Afghanistan and Pakistan
Reproduction
The rut takes place from late October to early January. During the rut, the males spend considerable effort courting females, and they are often emaciated from lack of grazing by the time it ends. Courtship lasts for over 30 minutes, and consists of licking, ritualised postures, and flehmen if the female urinates. Males compete for dominance during the rut, rearing up on their hind legs and clashing their horns together.
Gestation lasts 170 to 180 days, and usually results in the birth of a single kid, although twins occur in up to 14% of births, and triplets are born on rare occasions. Newborn kids weigh about , and grow rapidly during their first year. The horns are visible after about three to four weeks. They begin to eat grass as little as eight days after birth, but do not do so regularly until they are about one month old, and are not fully weaned until six months.
Males are sexually mature at eighteen months, but do not reach their full adult size for nine years. Females first breed in their second year. Males typically live for ten years in the wild, and females for up to seventeen years. They have been reported to live for up to 22 years in captivity.