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How Can The Camels Resist So Much Without Drinking Water?
- The "solution" is not the hump
By: Stefan Anitei, Science Editor



Camels are animals with a history. Some say that dromedary or Arabian camel (with one hump) could have been domesticated in southern Arabia between 6,000 to 3,400 years ago, while the larger and slower Bactrian camel (with two humps) in Central Asia about 3,500 years ago.

In the ninth century BC, dromedaries were used for warfare: not only were they used to carry archers, but also to transport heavy loads. In 853 BC, the Assyrian king Shalmaneser III faced an army made of Syrians and Jews joined by the Arabian king Gindibu, who led an army of 1,000 ...camel riders. The Assyrian chivalry got frightened at seeing these beasts and ran away. On the ruins of the city of Nineveh (the ancient Assyrian capital), on a relief can be seen the chivalry of king Assurbanipal (669-627 BC) fighting Arab camel riders.

The conquests of the Persian king Cyrus the Great (559-530) would have been impossible without logistical support of dromedaries. In c.547, he fought against king Croesus of Lydia (modern western Turkey) and employed these animals in what was to become one of the most famous stratagems of Antiquity: "He gathered all the dromedaries from his army train, took off their burdens and set cavalry men upon them. Having thus furnished them, he ordered them to go in front of the rest of the army towards the horsemen of Croesus [...]. He did this because horses are afraid of dromedaries and can not endure to see or smell them." The Persian king Cambyses (530-522 BC) introduced dromedaries in Egypt. The Persian king Xerxes (485-465 BC) was proud of his camels and their Arabian riders.

Domesticated camels
were used through much of North Africa, and the Romans maintained a corps of camel warriors to patrol the edge of the desert. Camels were also used by Romans for transportation, especially in the eastern provinces of Egypt, Arabia, Judaea, Syria, Cappadocia, and Mesopotamia. The Persian camels, however, were not particularly suited to trading or travel over the Sahara; rare journeys through the desert were made on horse-drawn chariots.

Julius Caesar considered the greatest war catch after the defeat of the Numidian king Juba’s camels. (Numidia is today northern Algeria). In 363 AD, general Romanus asked as a war tribute to the dwellers of the city Lepcis Magna (in present day Libya) 4,000 camels, for the transport of his army.

Much later, the Muslims claimed that Allah first created the camel, and after that the mountains, the deserts, the plains, the rivers, the seas and the other living things. Muhammad itself is said to have escaped from Mecca to Medina on the back of a camel.

The Islamic conquest of North Africa brought Arabian camels, well-suited to long desert journeys and which could carry a great deal of cargo. For the first time this allowed substantial trade over the Sahara. The Bactrian Camels were the main burden beast on the Silk Road, connecting China to Middle East.

Till today, many nomad tribes of the desert depend on the camels, like the Tuaregs of Sahara and Arab Bedouins, for transporting, milk, meat, wool and leather. In Mongolia, the Bactrian Camels offer the hair from which the felt, the material for traditional yurt tents, is made.

Camels are extremely well adapted to their environment, the desert. They can carry heavy cargoes, stand sand storms and large temperature differences. Camels are called the "desert ships", and they can swim when they encounter water. The north Egyptian lake Borollos has a depth varying between 20 cm and 2 m (0.6 to 6 ft). It cannot be crossed by boat or vehicles, and only camels can be used in this case.

A camel can resist 17 days without drinking under a scorching heat. It was wrongly believed its resistance resided in the water kept in the hump or in a stomach pouch. If it doesn’t drinking anything for 17 days, a camel can lose a third of its weight, without being affected. But when it catches the opportunity, in can drink 104 liters of water at once (the Bactrian Camel, which is larger, can drink up to 120 liters), in 7-8 minutes! But three days later, there is no sign of water in its stomach or hump.

To resist the lack of water, the camels have several means of adjusting to the situation. Their body temperature varies depending on the environment: in the cooler morning is of 34o C, during the hot afternoon it reaches 41o C. The kidneys' function is regulated depending on the water availability: they produce 7 liters of urine when water is abundant, and 500 g when it does not drink for days. When thirsty, transpiration is reduced towards zero.

A camel's thick coat reflects sunlight. A shorn camel has to sweat 50% more to avoid overheating. It also insulates them from the intense heat that radiates from hot desert sand. Their long legs help by keeping them further from the hot ground.

This ability to fluctuate body temperature and the efficiency of their sweating allows them to preserve about five liters of water a day.

Another issue: camels never run, they just speed up. Running would raise transpiration. They can make daily 160 km (100 miles) with a speed of 16 km (10 mi)/hour.

The camels' humps are reservoirs of fatty tissue. When this fat is metabolized, it is not only a source of energy, but yields through reaction with oxygen from the air 1,111 g of water per 1,000 g of fat converted. Though this metabolization of the fat generates a net loss of water through respiration during the process.

After drinking, water is spread uniformly in the body and it is lost gradually, about 100 liters in 17 days. The average water content of the camel's body is low: while the cow's tissues contain 80 % water, the donkey's (another desert animal) 65 %, and the camel's just 50 %. A camel crossing a desert loses in 24 hours only 2 % of its bodyweight, while the donkey at least 8 %. Curiously, wild Bactrian Camels from the Gobi desert (China-Mongolia) can drink saltwater.

Camels can withstand at least 20-25% weight loss due to sweating (most mammals can only withstand about 3-4% dehydration before cardiac failure results from the thickened blood). A camel's blood remains hydrated even though the body fluids are lost; until this 25% limit is reached.

But how can camels drink over 100 liters of water at once without serious consequences? This is the same as a human drinking 20 liters of water in 10 minutes. This would induce water intoxication in humans. It was found that the red blood cells of the camels have an ovoid shape and the property of swelling themselves, till achieving a double volume and after that gradually release the stored liquid.

The rest of the camel's body is adapted to the conditions in the desert: the hoof is perfect for the soft, instable sand; the thick eyebrows and eyelashes protect the eyes against sand and sun; the nostrils are moved by muscles that can close them hermetically (during the sand storms).

In their native lands, camels feel by far the presence of a fountain or river. They never forget the place where they have found water.

As a camel's mouth is extremely tough and pain resistant, they can eat without any problem thorny desert plants, which are avoided by other animals, even with spines so hard they can penetrate through a shoe's sole. Camels literally can survive on plant wastes, like an old twig basket or a mat.

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