Camelus dromedarius or dromedary is a large, even-toed ungulate with one hump on its back. It is the second largest of the three camel species; adult males stand 1.8–2 m tall at the shoulder, while females are 1.7–1.9 m tall. Males typically weigh between 400 and 600 kg, and females weigh between 300 and 540 kg. The species' distinctive features include its long, curved neck, narrow chest, single hump, and long hairs on the throat, shoulders and hump. The coat is generally a shade of brown. The hump is about 20 cm tall or more and is made of fat bound together by fibrous tissue.
Dromedaries are mainly active during daylight hours. They form herds of about 20 individuals, which are led by a dominant male. They feed on foliage and desert vegetation. Several adaptations, such as the ability to tolerate loss of more than 30% of the water content of the body, allow it to thrive in its desert habitat. Mating occurs annually and peaks in the rainy season; females bear a single calf after a gestation of 15 months.
The dromedary was probably first domesticated in Somalia or the Arabian Peninsula about 4,000 years ago. It has not occurred naturally in the wild for nearly 2,000 years but there were about 0.5 million dromedaries in Australia in 2005, the original animals having been introduced in 1840. They were also introduced to North America in the nineteenth century but do not appear to have survived there.
Prior to their domestication, the dromedary inhabited arid regions in the Old World, including the Sahara Desert. The domesticated dromedary is generally found in the semi-arid to arid regions of the Old World, mainly in Africa but also in Arabia. Products of the dromedary, including its meat and milk, support many families in these regions; it is also commonly used for riding and as a beast of burden.