Bactrian camel

The Bactrian camel (Camelus bactrianus), also known as the Mongolian camel, domestic Bactrian camel, two-humped camel or double humped camel is a camel native to the steppes of Central Asia. It has two humps on its back, in contrast to the single-humped dromedary. Its population of 2 million exists mainly in the domesticated form. Their name comes from the ancient historical region of Bactria.

Domesticated Bactrian camels have served as pack animals in inner Asia since ancient times. With its tolerance for cold, drought, and high altitudes, it enabled the travel of caravans on the Silk Road. Bactrian camels, whether domesticated or feral, are a separate species from the wild Bactrian camel (Camelus ferus), which is the only truly wild (as opposed to feral) species of camelid in the Old World. Domestic Bactrian camels do not descend from wild Bactrian camels, with the two species having split around 1 million years ago.

The Bactrian camel shares the genus Camelus with the dromedary (C. dromedarius) and the wild Bactrian camel (C. ferus). The Bactrian camel belongs to the family Camelidae. The ancient Greek philosopher Aristotle was the first European to describe the camels: in his 4th century BCE History of Animals, he identified the one-humped Arabian camel and the two-humped Bactrian camel. The Bactrian camel was given its current binomial name Camelus bactrianus by Swedish zoologist Carl Linnaeus in his 1758 publication Systema Naturae.

Though sharing a closer common ancestor with it than with the dromedary, the domestic Bactrian camel does not descend from the wild Bactrian camel, with the two species having diverged hundreds of thousands of years ago, with their mitochondrial genomes estimated to have diverged around 1 million years ago. Genetic evidence suggests that both Bactrian camel species are closely related to the extinct giant camel species Camelus knoblochi which became extinct around 20,000 years ago, which is equidistant from both living Bactrian camel species.

The Bactrian camel and the dromedary often interbreed to produce fertile offspring. Where the ranges of the two species overlap, such as in northern Punjab, Iran and Afghanistan, the phenotypic differences between them tend to decrease as a result of extensive crossbreeding between them. The fertility of their hybrid has given rise to speculation that the Bactrian camel and the dromedary should be merged into a single species with two varieties. However, a 1994 analysis of the mitochondrial cytochrome b gene revealed that the species display 10.3% divergence in their sequences.

The Bactrian camel is the largest mammal in its native range and is the largest living camel while being shorter at the shoulder than the dromedary. Shoulder height is from 160 to 180 cm (5.2 to 5.9 ft) with the overall height ranging from 230 to 250 cm (7.5 to 8.2 ft), head-and-body length is 225–350 cm (7.38–11.48 ft), and the tail length is 35–55 cm (14–22 in). At the top of the humps, the average height is 213 cm (6.99 ft).

Body mass can range from 300 to 1,000 kg (660 to 2,200 lb), with males weighing around 600 kg (1,300 lb), and females around 480 kg (1,060 lb). Its long, wooly coat varies in colour from dark brown to sandy beige. A mane and beard of long hair occurs on the neck and throat, with hairs measuring up to 25 cm (9.8 in) long.

The shaggy winter coat is shed extremely rapidly, with huge sections peeling off at once, appearing as if sloppily shorn. The two humps on the back are composed of fat (not water as is sometimes thought). The face is typical of a camelid, being long and somewhat triangular, with a split upper lip. The long eyelashes, along with the sealable nostrils, help to keep out dust in the frequent sandstorms which occur in their natural range. The two broad toes on each foot have undivided soles and are able to spread widely as an adaptation to walking on sand. The feet are very tough, as befits an animal of extreme environments.