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Classification
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Camelus
dromedarius
Dromedary, Arabian camel
Taxonomy
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photographs
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General Characteristics
Body Length: 300 cm / 10 ft.
Shoulder Height: 180-210 cm / 6-7 ft.
Tail Length: 50 cm / 20 in.
Weight: 600-1000 kg / 1320-2200 lb.The smooth coat is beige to light brown in wild-type individuals, with the undersides slightly lighter. However, selective breeding has also produced forms that vary from dark brown to white. The legs are long and slender, with callouses on the 'knees' where they touch the ground when the animal is lying down. Though often called the one-humped camel, the dromedary has two humps used for energy storage in the form of fat. The under-developed anterior hump sits over the shoulders and the large rear hump is found in the centre of the back. The upper lip is deeply split, and the nostrils can be closed. There are long eyelashes, which help to keep sand out of the eyes. The two broad toes on the feet are able to spread widely as an adaptation to walking on sand.
Ontogeny and Reproduction
Gestation Period: 12-13 months.
Young per Birth: 1
Weaning: At 1-2 years.
Sexual Maturity: Females at 3-4 years, males at 5-6 years.
Life span: 40 years.The overall birthing season extends from January to May, although each region has a shorter, more defined spread.
Ecology and Behavior
The ability of the camel to survive in desert conditions without water for long periods of time is rivalled by none. The many physiological adaptations the dromedary have even earned it the title "ship of the desert". Dromedaries can glean much of their needed water from desert vegetation, and can survive after losing over 40 percent of their body weight in water. When water is available, whether fresh or brackish (salty), camels drink well - up to 57 litres at a time. Camels also have a flexible 'thermostat', and will not start sweating until their body temperature reaches 42oC / 107.5oF. Nor do heating mechanisms kick in during the cooler nights until the internal temperature reaches 34oC / 92oF. Besides saving energy, this physiological adaptation allows the camel to "store" coolness in preparation for the next day. On hot days, dromedaries will rest together in closely packed groups, with reduces the heat reflecting off of the ground considerably. Wild-type behaviour has been studied mostly in Australia, where the animals are not influenced by people. Groups are in no way territorial, and during droughts may join up with other groups, forming large herds of several hundred animals. Large migrations may be undertaken by these groups in the search for water. During the reproductive season, males splash their urine on their tails, which is flicked up and down, sprinkling the back and surrounding area. Meanwhile, male dromedaries also extrude their soft palate, which hangs out of the side of their mouth like a red balloon. Copious saliva turns to foam as the male gurgles, covering the mouth. During the breeding season males become very aggressive towards each other, defending their groups of females from all rivals. Conflicts are often serious, consisting of snapping at each other while attempting to neck-wrestle the other to the ground. Suffocation of the loser may occur if a male succeeds in felling his opponent with the rival's head between the winners leg and body. The main vocalizations include a sheep-like bleat used to locate individuals and the breeding gurgle of males, while a whistling noise is produced as a threat noise by males by grinding the teeth together.Family group: Feral herds of females and young led by an adult male, generally with fewer than 21 individuals, other males solitary or in bachelor groups.
Diet: Leaves, grasses.
Main Predators: None known.
Distribution
Deserts in northern Africa, Arabia, and the Middle East, while a feral population is found in Australia.
Range Map (Redrawn from Köhler-Rollefson, 1991)
Conservation Status
All true wild dromedaries are extinct. However, the population of domestic dromedaries is approximately 15 million, rendering their status common.
Remarks
The dromedary, or one-humped camel, was described by Linnaeus in 1758. There are no true wild dromedaries in the world today - they were domesticated between 4,000 and 2,000 B.C.E. for travel, meat and milk, and running, and became extinct in the wild around 2000 years ago. A large feral population (estimated between 25,000-80,000 individuals) exists in the Australian outback, descended from pack animals imported between 1840 and 1907. Dromedaries were also introduced into the southwestern United States in the middle of the 19th century for both transportation and meat, but due to the building of the railroads, the experiment was declared useless. Many of these camels were turned loose, and feral populations survived until the early 1900's. Despite its common name "one-humped camel", the dromedary actually has two humps, although only the rear one is fully developed. A simple way to remember which camel is a Bactrian and which is a Dromedary - if you rotate the first letter of the name so it sits flat, you will get the basic profile of the animal (and the approximate visual representation of the humps). Camelus (Latin) a camel. Dromeus (Greek) a runner; -arius (Layin) suffix meaning pertaining to: hence dromedarius (New Latin) a running camel.
Literature Cited
Klingel, H. 1990. Camels. In Grzimek's Encyclopedia of Mammals. Edited by S. P. Parker. New York: McGraw-Hill. Volume 5, pp. 85-96.Köhler-Rollefson, I. U. 1991. Camelus dromedarius. Mammalian Species (375): 1-8.
Nowak, R. M. [editor]. 1991. Walker's Mammals of the World (Fifth Edition). Baltimore: The Johns Hopkins University Press.
Wilson, D. E., and D. M. Reeder [editors]. 1993. Mammal Species of the World (Second Edition). Washington: Smithsonian Institution Press. Available online at http://nmnhwww.si.edu/msw/
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