Camels are even-toed ungulates within the genus Camelus. The dromedary, one-humped or Arabian camel has a single hump, and the Bactrian camel has two humps. They are native to the dry desert areas of western Asia, and central and east Asia, respectively.

The average life expectancy of a camel is forty to fifty years. The term camel is also used more broadly to describe any of the six camellike creatures in the family Camelidae: the two true camels, and the four South American camelids, the llama, alpaca, guanaco, and vicuña.

A fully-grown adult camel stands at the shoulder and at the hump. The hump rises about thirty inches (75 cm) out of its body. Camels can run up to in short bursts and sustain speeds of up to .

Fossil evidence indicates that the ancestors of modern camels evolved in North America during the Palaeogene period, and later spread to Asia. Humans first domesticated camels before 2000 BC . The dromedary and the Bactrian camel are both still used for milk, meat, and as beasts of burden—the dromedary in western Asia, and the Bactrian camel further to the north and east in central Asia.

Distribution and numbers

The almost 14 million dromedaries alive today are domesticated animals (mostly living in Somalia, Sudan, Mauritania and nearby countries).

The Bactrian camel is now reduced to an estimated 1.4 million animals, mostly domesticated. It is thought that there are about 1000 wild Bactrian camels in the Gobi Desert in China and Mongolia.

There is a substantial feral population of dromedaries estimated at up to 700,000 in central parts of Australia, descended from individuals introduced as transport animals in the 19th century and early 20th century. This population is growing at approximately 11% per year. The government of South Australia has decided to cull the animals using aerial marksmen, because the camels use too much of the limited resources needed by sheep farmers. For more information, see Australian feral camel.

A small population of introduced camels, dromedaries and Bactrians, survived in the Southwest United States until the 1900s. These animals, imported from Turkey, were part of the US Camel Corps experiment and used as draft animals in mines and escaped or were released after the project was terminated. A descendant of one of these was seen by a backpacker in Los Padres National Forest in 1972. Twenty-three Bactrian camels were brought to Canada during the Cariboo Gold Rush.

Genetics

The karyotypes of different camelid species have been studied by many groups , but no agreement on chromosome nomenclature of camelids has been reached. The most recent study used flow-sorted camel chromosomes building undoubtedly the camel's karyotype (2n=74) that consists of one metacentric, three submetacentric and 32 acrocentric autosomes. The Y is a small metacentric chromosome, while the X is a large metacentric chromosome. . According to molecular data, the New World and Old World camelids diverged 11 million years ago. In spite of this, these species turned out to be conserved sufficiently to hybridize and produce live offspring (cama). The dromedary-guanaco interspecific hybrid provided the ideal platform to compare the karyotypes of Old World and New World camels.