Bactrian camel

The Bactrian camel, also called the Mongolian or two-humped camel, is native to Central Asia’s steppes. Unlike the single-humped dromedary, it has two humps. Most of its roughly 2 million members are domesticated. Its name comes from the ancient region of Bactria. Since ancient times, these camels have been used as pack animals in inner Asia, and their ability to endure cold, drought, and high altitudes made Silk Road caravans possible.

In taxonomy, the Bactrian camel shares the genus *Camelus* with the dromedary and the wild Bactrian camel (*C. ferus*). It belongs to the family Camelidae. The Greek philosopher Aristotle was the first European to describe camels, noting both the one-humped Arabian and two-humped Bactrian types in his 4th-century BCE *History of Animals*. Swedish zoologist Carl Linnaeus gave the Bactrian camel its scientific name, *Camelus bactrianus*, in his 1758 work *Systema Naturae*. Although the domestic Bactrian camel shares a closer common ancestor with the wild Bactrian camel than with the dromedary, it did not descend from it; the two species split hundreds of thousands of years ago, with their mitochondrial genomes diverging about 1 million years ago. Genetic evidence links both Bactrian camel species to the extinct giant camel *Camelus knoblochi*, which died out around 20,000 years ago and is equally related to both.

The Bactrian camel and the dromedary often interbreed and produce fertile offspring. Where their ranges overlap—such as in northern Punjab, Iran, and Afghanistan—their physical differences tend to blur due to extensive crossbreeding. This hybrid fertility has led some to suggest the two should be considered a single species with two varieties. However, a 1994 analysis of the mitochondrial cytochrome b gene found a 10.3% divergence in their sequences.

The Bactrian camel is the largest mammal in its native range and the largest living camel, though it is shorter at the shoulder than the dromedary. Shoulder height ranges from 160 to 180 cm (5.2–5.9 ft), total height from 230 to 250 cm (7.5–8.2 ft), head-and-body length from 225 to 350 cm (7.38–11.48 ft), and tail length from 35 to 55 cm (14–22 in). At the top of the humps, average height is 213 cm (6.99 ft). Body mass varies from 300 to 1,000 kg (660–2,200 lb), with males averaging about 600 kg (1,300 lb) and females about 480 kg (1,060 lb). Its long, woolly coat ranges from dark brown to sandy beige, with a mane and beard of long hair on the neck and throat that can reach 25 cm (9.8 in). The shaggy winter coat sheds very quickly, with large patches peeling off at once. The two humps are made of fat, not water. The face is long and somewhat triangular, with a split upper lip. Long eyelashes and sealable nostrils help keep out dust during sandstorms. Each foot has two broad toes with undivided soles that spread wide for walking on sand, and the feet are very tough.

These camels are migratory, living in habitats from rocky mountains to flat steppe, arid desert (mostly the Gobi Desert), stony plains, and sand dunes. Conditions are extreme: sparse vegetation, limited water, and temperatures from as low as −30 °C (−22 °F) in winter to 50 °C (122 °F) in summer. Their distribution depends on water availability, with large groups gathering near rivers after rain, at mountain springs in summer, or where snow is available in winter.

Bactrian camels handle huge temperature swings and can go months without water, but when water is available they may drink up to 57 L (13 imp gal; 15 US gal). A thirsty camel in a hot, dry season can consume up to 200 L (44 imp gal; 53 US gal) in a single day. When well fed, their humps are plump and upright; when resources are scarce, they shrink and lean to one side. At speeds faster than a walk, they pace—moving both legs on the same side forward together—rather than trot. They have been recorded at speeds up to 65 km/h (40 mph) but rarely move that fast, usually sustaining about 40 km/h (25 mph). Domestic Bactrian camels have been seen swimming. Their sight is good, and their sense of smell is excellent. In the wild, they can live up to 50 years, though the average is around 30; domesticated ones have not been recorded living beyond 35 years.

Bactrian camels are diurnal, sleeping in the open at night and foraging during the day. They are mainly herbivores.