A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as "humps" on its back. The two surviving species of camel are the dromedary, or one-humped camel, which is native to the Middle East and the Horn of Africa; and the Bactrian, or two-humped camel, which inhabits Central Asia. Both species have been domesticated; they provide milk, meat, hair for textiles or goods such as felted pouches, and are working animals.
The dromedary (pronounced /ˈdrɑmədɛɹi/or/ˈdrɒmədri/) or Arabian camel (Camelus dromedarius) is a large, even-toed ungulate with one hump on its back. First described by Aristotle of Stagira, the dromedary was given its binomial name by Carl Linnaeus in 1758. The dromedary is the next largest member of the camel family after the Bactrian camel. The oldest known ancestor of the dromedary is the Protylopus. Males are 1.8–2 m (5.9–6.6 ft) tall and females 1.7–1.9 m (5.6–6.2 ft) tall. Males range from 400–600 kg (880–1,300 lb), while females weigh 300–540 kg (660–1,200 lb). They vary in colour from a light beige to dark brown. The notable hump, measuring 20 cm (7.9 in) high, is composed of fat bound together by fibrous tissue.
Their diet includes foliage and desert vegetation, like thorny plants which their extremely tough mouths allow them to eat. The camels are active in the day, and rest together in groups. Led by a dominant male, each herd consists of about 20 individuals. Some males form bachelor groups. Dromedaries show no signs of territoriality, as herds often merge during calamities. Predators in the wild include wolves, lions and tigers. Dromedaries use a wide set of vocalizations to communicate with each other. They have various adaptations to help them exist in their desert habitat. Dromedaries have bushy eyebrows and two rows of long eyelashes to protect their eyes and can close their nostrils to face sandstorms. Their ears are also lined with protective hair. When water-deprived they can fluctuate their body temperature by 6 degrees C, changing from a morning minimum of 34 degrees to a maximum of 40 degrees or so in the afternoon. This is to allow heat flow from the environment to the body to be reduced and thereby water loss through perspiration is prevented. They have specialized kidneys, which make them able to tolerate water loss of more than 30% of their body mass; a loss of 15% would prove fatal in most other animals. Mating usually occurs in winter, often overlapping the rainy season. One calf is born after the gestational period of 15 months, and is nurtured for about two years.