Camel - biology.

« 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 fatalfor 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 excretesvery 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 constantbody temperature in hot conditions primarily through sweating, which cools the body but also leads to a higher metabolism and heavier breathing.

The camel thereforeloses 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.

Thisprevents heart failure due to thickening of the blood, which occurs in other mammals suffering extreme dehydration.

Finally, when water becomes available adehydrated 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 inAfrica.

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 makingtents 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 thedesert 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 oftenraced 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 8thcenturies owed much to camel caravans, which traversed previously impenetrable regions in Arabia, the Middle East, and Saharan Africa.

Camels were also used incombat 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 packanimals 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 freewhen 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 theU.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 roadsand 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 windsweptsand 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 14thcentury, when Tombouctou was a leading terminus of trans-Saharan caravans and a distribution point for trade along the upper Niger River.

Camel caravans are alsocommonly 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 likethe 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 theTitanotylopus , 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 . Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation.

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