The 4 surviving species in this formerly more diverse family are the most primitive of the ruminants, or cud-chewing animals. Of the 4, dromedaries and most of the Bactrian camels are wholly domesticated. There are still wild Bactrians in the Gobi Desert, and guanacos and vicunas maintain wild populations in parts of South America.
Camels and their relatives have highly specialized feet. They have evolved to the point of having only two toes on each foot, but the foot bones are expanded sideways to produce the support for two broad, flat pads on each foot, with a nail on the upper surface of each toe. This foot structure is particularly well developed in the camel species and it enables them to walk on soft, sandy soil, where conventional hoofs would sink in deeply.
The head of a camelid is relatively small, with an elongate snout terminating in a cleft upper lip. Vegetation is cropped by using long, forward-pointing lower incisors that work against tough upper gums. Camelids have complex three-chambered stomachs and ruminate, or chew the cud.
The humps of the 2 species of camel are fat stores, which provide food reserves — vital in the unpredictable conditions of the camel’s desert habitat.Bactrian Camel
Range: C. Asia: China, Mongolia
Habitat: Desert, steppe
Size: Body: about 9 ¾ ft (3 m); Tail: about 21 in (53 cm)
The Bactrian (two-humped) camel has been domesticated, but has not spread outside its native range to the same extent as the dromedary. Only a small number of Bactrian camels live wild in the Gobi Desert, and even these may be part domestic stock. It is thought that Mongolian stocks may be slowly increasing.
Apart from its two humps, the main characteristic of the Bactrian camel is its long, shaggy hair, which keeps it warm in winter, but is shed in summer, leaving the body almost naked. Docile, slow moving animals, these camels move with a rolling gait which is the result of their ability to raise both legs on one side at the same time. They feed on virtually any vegetation, such as grass, the foliage of trees and bushes, and small plants.
After a gestation of 370 to 440 days, the female gives birth to 1 young, which is active within only 24 hours. It is suckled for about a year and fully grown when about 5 years old.Dromedary
Range: N. Africa, Middle East; introduced in Australia
Habitat: Semiarid and arid grassland, desert, plains
Size: Body: 7¼ - 11 ft (2.2 – 3.4 m); Tail: 19¾ in (50 cm)
The dromedary, or one-humped camel now exists only as a domesticated animal, which it has been, so it is thought, since 4000 B.C. Before then it probably lived in North Africa and Arabia. Today there are two main types: a heavily built, slow-moving animal used as a beast of burden, and a light graceful, fast-running racer, used for riding. Both have short, coarse hair, longest on the crown, neck, throat and hump.
Dromedaries feed on grass and any other plants and can survive in areas of sparse, tough vegetation Certain adaptations fit the dromedary for life in hot, dry climates; the most significant is its ability to go for long periods without drinking, linked with its ability to conserve water in the body. Its hump is an important' specialization. It gives protection from the sun by absorbing heat and carries fat stores, which are metabolized to provide energy and water. The camel does not store water in the hump, but can do so in the stomach lining. The kidneys are able to concentrate urine to avoid water loss, and moisture can be absorbed from fecal material. The body temperature of the camel drops at night and rises so slowly during the day that the animal does not need to sweat to cool itself for a long time. During an extended period without water, the camel is able to lose up to 27 per cent of its body weight without detrimental effect. This loss can be recovered in 10 minutes by drinking. In one experiment, a thirsty camel drank 104 litres (27 gal) in a few minutes.
Females breed every other year. After a gestation of 365 to 440 days, the female moves away from the herd to give birth to a single calf. When it is able to walk, after a day or so, they rejoin the herd. The calf is suckled for almost a year, but starts to nibble plants as soon as it is born, and by 2 months old is regularly eating vegetation.