Camel

III

Physical Description

A full-grown camel weighs from 300 to 690 kg (660 to 1,520 lb). It stands about 2 m (6.5 ft) tall at the shoulders, and the hump rises about 30 cm (12 in) above the back. The Bactrian camel has more pointed humps, a stockier body, and slightly shorter legs than the Arabian camel. The Arabian camel appears to have only one hump, but it actually has two, like the Bactrian. However, the front hump is undeveloped in the Arabian.

The camel is classified as an ungulate (hoofed mammal). However, the camel’s broad, two-toed feet are not encased in horny hooves like other ungulates, such as cattle and deer. The soles of a camel’s feet have thick, leathery pads that spread when the animal walks, preventing it from sinking in soft sand and snow. The Bactrian camel has harder feet than the Arabian camel, making it better adapted to rocky terrain. The camel moves in a pacing gait, with the front leg and hind leg on one side moving forward simultaneously. This pacing produces a swaying motion.

The camel has a long, curved neck and an elongated head. Its slitlike nostrils can be almost completely closed, and the hairy lining filters out sand and dust during a desert storm. A deep groove from the nostrils to the upper cleft lip allows the mouth to capture any moisture from the nostrils. A double row of long, thick eyelashes shields the animal’s eyes from flying particles of grit and sand. A pad of connective tissue on the chest and thick knee pads provide protection from the hot sand when the camel is lying down.

The camel has a coat of woolly hair, which becomes long and thick in cold regions and in winter. The camel rapidly sheds its winter coat in large, clotted masses in the spring and early summer. The hair color varies from cream to deep brown.

---

---

Camels have three-chambered stomachs and digest their food in two steps. They quickly swallow their food and then regurgitate the partially digested food, called cud, to chew it thoroughly before fully digesting it. Camels are known to spit out their cud when they become agitated or frightened. In this way, the camel attempts to distract or surprise whatever it finds threatening. Unlike most cud-chewing mammals, camels have sharp front teeth and can inflict a damaging bite.

IV

Survival in the Desert

Camels are extremely well adapted to their desert environment. Both Arabian and Bactrian camels can survive in extreme temperatures. In the Sahara, for example, temperatures range from freezing to more than 54°C (more than 130°F). The camel can withstand changes in its internal body temperature that would cause most other mammals to die. In hot weather, the camel’s body temperature may rise to 42°C (107.6°F). In cold weather, the camel’s body temperature may lower to 34°C (93°F). In comparison, most mammals, including humans, must maintain their body temperature generally constant at about 37°C (98.6°F).

Camels eat most types of desert vegetation, including thorny shrubs. They can even eat plants that are poisonous to other animals. The camel’s humps are stores of fat that the animal’s body absorbs as nutrients when there is a lack of food. The hump is tall and firm in a well-fed camel, but it will shrink and become soft and flabby in an undernourished camel. Although the hump is an important energy reserve, it is not what allows the camel to subsist for long periods without water.

Camels will drink brackish (salty) water if necessary. Like any other mammal, camels drink to make up for previous water losses. Their bodies do not contain a reserve of water in the stomach or hump as was once commonly believed. Unlike other mammals, however, the camel can survive as long as three weeks without drinking, depending on the water content of its food. It can survive a water loss of about 40 percent of its normal body weight. In comparison, a loss of 15 percent is usually fatal for humans.

Camels can go without water due to several unique adaptations to their environment. The camel conserves more water in its body than any other mammal. It excretes very little water in its urine and dung. It has the ability to maintain a high body temperature, and its skin has almost no sweat glands. Mammals maintain a constant body temperature in hot conditions primarily through sweating, which cools the body but also leads to a higher metabolism and heavier breathing. The camel therefore loses less water through perspiration and through evaporation of water from the lungs than do most other mammals.

In addition, the camel’s blood remains fluid when the animal becomes dehydrated because water lost from the blood is replaced by water from other tissues. This prevents heart failure due to thickening of the blood, which occurs in other mammals suffering extreme dehydration. Finally, when water becomes available a dehydrated camel is able to consume as much as 57 liters (15 gallons) at once. This allows the camel to restore its body fluids quickly.

V

Camels and People

Most of the world’s domesticated camels belong to nomadic and seminomadic herders, such as the Berber-speaking Tuareg people of the Sahara and Sahel regions in Africa. They highly value the camel’s flesh and milk for food, its hide for leather, and its woolly hair for making cloth. This warm, long-napped cloth is used for making tents that shelter the nomads during cold desert nights. The camel’s exceptionally dry dung is burned for fuel. Nomadic herders can subsist for long periods in the desert without water by drinking camel’s milk, which contains three times more ascorbic acid (vitamin C) than cow’s milk and is also high in iron and B vitamins.

The endurance and strength of the camel have made it a valuable beast of burden for thousands of years. The camel can carry loads as great as 450 kg (990 lb), although a more comfortable load is 150 kg (330 lb). With a cargo, the camel’s pace is only about 4 km/h (about 2.5 mph), but it can travel as much as 47 km (29 mi) in a day. The Arabian camel is also commonly used for riding, and as a saddle animal it can cover more than 161 km (more than 100 mi) in a day. Camels are often raced against one another. At a full gallop, the camel can reach speeds of 19 km/hr (12 mph).

Historically, camels were used in caravans traveling the ancient trading routes across Asia known as the Silk Road. The rapid spread of Islam in the 7th and 8th centuries owed much to camel caravans, which traversed previously impenetrable regions in Arabia, the Middle East, and Saharan Africa. Camels were also used in combat and for other military purposes from ancient times to as recently as the 1960s.

Camels have been used beyond their native regions, as well. Thousands of camels were imported to Australia from 1840 to 1907. People used them as draft and pack animals in the building of telegraph and railroad lines in the continent’s arid interior regions, known as the outback. These domesticated camels were simply set free when no longer needed, and their numbers have multiplied in the wild. About 500,000 feral Arabian camels currently live in the Australian outback.

Arabian camels were also imported to the southwestern United States in the 1850s as saddle and pack animals for the U.S. military. Forming what was known as the U.S. Camel Corps, these animals were soon replaced by railroads and other means of transportation and eventually died out.

Modern forms of transportation have reduced the camel’s usefulness. However, camel caravans are still common in some places, especially where the building of roads and railroads is not feasible. In the African country of Mali, for example, camel caravans continue to transport blocks of salt from mines in Taoudenni across windswept sand dunes to Tombouctou. The trip covers a distance of 800 km (500 mi) and lasts two weeks. Camels have transported salt on this route since at least the 14th century, when Tombouctou was a leading terminus of trans-Saharan caravans and a distribution point for trade along the upper Niger River. Camel caravans are also commonly used to transport goods across the Thar Desert in northwestern India and eastern Pakistan.

VI

Evolution of the Camel

Fossil remains indicate that the camel family, Camelidae, originated in North America about 40 million years ago. The earliest camelids were about the size of rabbits, but over time they grew in size and multiplied in species until the plains and prairies teemed with many different types. By about 5 million years ago, giant camelids like the Titanotylopus, which stood about 3.5 m (about 11.5 ft) tall at the shoulder, lived in North America. Camelids probably migrated to Asia and South America during the Pliocene and Pleistocene epochs, when land bridges connected those continents to North America. Their descendants in South America are the llama, alpaca, guanaco, and vicuña. Camelids became extinct in North America about 11,000 years ago.

In 2006 archaeologists announced the discovery of 100,000-year-old fossilized remains of a previously unknown giant camel species in central Syria. Like the Titanotylopus, it stood about twice the size of the modern camel. Before the discovery, it had been unknown that the camel lived in the Middle East more than 10,000 years ago.

Scientific classification: Camels belong to the family Camelidae, which also includes llamas, alpacas, guanacos, and vicuñas. Camels make up the genus Camelus. The Arabian camel is classified as Camelus dromedarius, and the Bactrian camel is Camelus bactrianus.

	More from Encarta
	•  Presidential Myths Quiz •  Coffee break: Recharge your brain