Dromedary Camel: One-Humped Camel Facts and Adaptations

What is a dromedary camel?

The dromedary is one of three living species of true camels in the genus Camelus. The other two are the domestic Bactrian camel and the much rarer wild Bactrian camel, which both have two humps; the differences are explained in dromedary vs Bactrian camel. Camels belong to the family Camelidae together with the South American llama, alpaca, guanaco and vicuña.

The name comes from the Greek dromas, meaning “runner”. The dromedary exists today almost entirely as a domestic animal. Its wild ancestors once roamed the Arabian Peninsula but disappeared roughly 2,000 years ago, so the species is not assessed on the IUCN Red List and is classed here as Domesticated.

Appearance and size

A dromedary has long, powerful legs, a long curved neck, a deep but narrow chest and one hump in the middle of the back. The coat is short and usually sandy or caramel brown, but it ranges from almost black to nearly white, and some animals are piebald. The hair is longest on the throat, shoulders and hump.

It is the tallest of the camels. Adult males stand about 1.8–2.4 m (5.9–7.9 ft) at the shoulder and weigh 400–690 kg (880–1,520 lb). Females are smaller, at 1.7–1.9 m (5.6–6.2 ft) and 300–540 kg (660–1,190 lb). The hump adds at least 20 cm (8 in) more on top of the shoulder height.

Like all camels, the dromedary has two toes on each foot joined to a broad, flat, leathery pad. The pads spread its weight on soft sand, but they slip on wet mud and can be cut by sharp stones. Thick, hardened pads of skin on the chest and knees act as cushions when the camel kneels on hot ground. Unusually, camels walk with a “pace”, moving both legs on the same side of the body at the same time, which gives their rocking stride.

Adult males have a bright pink, balloon-like flap called the dulla, which is part of the soft palate. In the breeding season they inflate it and let it hang out of the side of the mouth, together with a lot of foamy saliva, to impress females and rivals.

The hump: fat, not water

The single hump is a store of fat held together by fibrous tissue, and in a well-fed animal it can hold up to about 36 kg (80 lb) of fat. When food is scarce the camel burns this fat for energy, and the hump shrinks, goes soft and may flop to one side. A firm, upright hump is a sign of a camel in good condition.

Keeping most of the body’s fat in one place on the back also helps with heat. A thin layer of fat spread all over the body, as in many mammals, would act like a blanket; packing it into the hump lets heat escape from the rest of the skin. The full story, including why the hump is not a water tank, is in What is in a camel’s hump?.

How dromedaries survive the desert

The dromedary’s real secret is not storing water but saving it. Several adaptations work together:

• A flexible body temperature. A dromedary’s temperature can drift from about 34 °C (93 °F) at dawn to almost 42 °C (107 °F) by late afternoon. Instead of sweating to stay cool, it soaks up heat during the day and lets it go in the cold desert night, saving liters of water.
• Tolerating dehydration. A dromedary can survive losing more than 30% of its body water, while most mammals die after losing about 15%. Much of the water lost comes from tissues rather than the blood, so the blood stays thin enough to carry heat away from the body.
• Oval red blood cells. Camels and their relatives are the only mammals with oval rather than round red blood cells. These keep flowing when the blood thickens and can swell when the camel drinks a huge amount at once.
• Kidneys and gut that waste little. The kidneys produce very concentrated urine, and the dung is so dry it can be burned as fuel soon after it is dropped.
• Nose and eyes for sandstorms. The slit-shaped nostrils can be closed against blowing sand and also recapture moisture from breath. A double row of long eyelashes, bushy eyebrows and a thin third eyelid protect the eyes.

When it does find water, a thirsty dromedary can drink about 100 liters (26 US gallons) in around 10 minutes, an amount that would be dangerous for most other mammals. How long it can last between drinks is covered in How long can a camel go without water?.

Habitat and range

Dromedaries thrive in hot, dry places with a long dry season and a short rainy season, from sand seas and gravel plains to dry scrub and semi-desert grassland. They are sensitive to cold and damp, and attempts to keep them in wet climates have mostly failed.

Today the species lives under human care across North Africa and the Sahel, the Horn of Africa, the Arabian Peninsula, the Middle East, Iran, Pakistan and northwest India. Africa holds more than 80% of the world’s dromedaries, and Somalia, Sudan, Ethiopia and Kenya have some of the largest herds. Small populations also live in the Canary Islands, where camels were brought in the 15th century.

The one large free-living population is in central Australia. Camels were imported there in the 1800s to carry supplies across the outback and were later released; their descendants now form the world’s largest herd of dromedaries living without human control. Why it happened is told in Why are there wild camels in Australia?.

What do dromedaries eat?

Dromedaries are herbivores and mainly browsers, eating the leaves, twigs and pods of shrubs and trees as well as dry grasses and herbs. One study of camels in the Sahara recorded more than 300 plant species in their diet, including acacias and saltbushes. Tough lips and a hard palate let them eat thorny plants that most other animals avoid, and they can reach leaves up to about 3.5 m (11.5 ft) high.

Salty plants are an important part of the diet, because camels need much more salt than most livestock. Like cattle, dromedaries chew the cud: they spend about 8–12 hours a day feeding and a similar time ruminating. Their stomach has three chambers rather than four, so camels are not counted as true ruminants. When foraging they take only a few bites from each plant before moving on, which spreads their impact across the landscape.

Behavior and herd life

Dromedaries are active by day and rest at night, and often lie down through the hottest hours around midday. Herds usually number up to about 20 animals: several females and their young led by one dominant male, while other males form bachelor groups or wander alone. Females often take turns leading the group as it travels in single file.

Outside the breeding season dromedaries are mostly calm. During the rut, however, males become aggressive. They gurgle loudly, blow out the dulla, splash urine on their tails and wrestle rivals by biting at their legs and pressing down on their necks. Camels also “spit”: when annoyed they may bring up a smelly mix of saliva and stomach contents.

Reproduction, life cycle and lifespan

Breeding usually peaks in the cool, rainy part of the year, and females are induced ovulators, releasing an egg after mating. Pregnancy is long, about 13 to 15 months (370–440 days), and nearly always produces a single calf. A newborn typically weighs about 35 kg (77 lb) and can walk within hours of birth.

Calves nurse for one to two years, and a female usually gives birth only once every two years. Females can breed from about three to four years old, while males are not fully mature until around six. This slow breeding means camel herds grow slowly compared with sheep or goat herds.

Dromedaries are long-lived for their size. A lifespan of about 40 years is often given, and some animals in captivity have been reported to reach around 50. Working camels usually remain useful for 20 years or more.

Predators and threats

In the past, free-ranging dromedaries faced lions, leopards, hyenas, wolves and, in parts of Asia, tigers. Today most dromedaries are guarded livestock, and calves are the main target of predators such as hyenas and stray dogs. The greater threats are drought, disease and the decline of traditional herding as roads and trucks replace camel caravans.

Relationship with people

The dromedary was probably first domesticated in the southeastern Arabian Peninsula roughly 3,000 to 4,000 years ago, and it spread to North Africa in ancient times. Camel caravans made long-distance trade across the Sahara and Arabia possible, carrying salt, gold, spices and textiles. A strong camel can carry loads of 150–300 kg (330–660 lb) for long distances.

Dromedaries are still vital to many pastoral peoples. They provide milk, which is a staple in parts of the Horn of Africa, as well as meat, leather and hair. Camel racing is a major sport in the Gulf states, and camel beauty contests draw large crowds. The Food and Agriculture Organization estimates that the world has about 35 million or more camels, and most of them are dromedaries.

Myths and facts

• Myth: camels store water in their humps. Fact: the hump is fat. Camels save water through their body temperature, kidneys, nose and blood.
• Myth: camels have always lived in Arabia. Fact: the camel family evolved in North America. The ancestors of modern camels crossed into Asia over the Bering land bridge about 7 million years ago, and the last native North American camels died out at the end of the last ice age.
• Myth: a dromedary is a different animal from a camel. Fact: the dromedary is a camel, the one-humped species. “Camel” covers both the dromedary and the two-humped Bactrian camels.