Camels - King of the desert
Camel, a large cud-chewing mammal with one or two humps on the back, found in the arid regions of Africa, Asia, and Australia.
In prehistoric times camels roamed on all of the continents except Australia and Antarctica. Camels originated in North America but became extinct there about 11,000 years ago. Desert-dwelling people in Asia domesticated the camel more than 3,000 years ago. Since then, people have relied on the camel as a means of transportation and a source of milk, meat, wool, and hides. Often called the “ship of the desert,” the camel is known for its incredible endurance as a pack animal. The camel is unrivaled among mammals in its ability to survive for long periods of time without food and water. The fatty humps on the camel’s back provide nutrition when no food is available.
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).
Theyeat 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.
Theywill 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.
They 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.
Finally, 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.
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