John Simon, age 12, of Sioux City, Iowa for his question:
Why do camels have humps?
Scientists have traced the camel's family tree way back through fifty million years. The original ancestors were small, humpless animals who lived where food and water were plentiful. But for reasons unknown they were wanderers and through the ages some of them wandered to the arid deserts of Asia. There they gradually developed humps and other adaptations to store extra food, water and energy.
Textbooks written twenty years ago tell us that the camel stores food in his hump and water in his stomach. Chances are, there were diagrams showing small pockets in the walls of two of his four stomachs, where his extra water was supposed to be stored. Then, in the 1950's, a team of researchers went to the Sahara Desert to re study the camel's storage secrets. And the famous old stories must be re written.
The experts studied the one humped Arabian camel of Africa. This more familiar animal is a fairly recent cousin of the two humped Bactrian camel of the Gobi Desert region of Asia.
In ten minutes, a thirsty camel can drink more than 25 gallons of water and after a period of feasting he adds about 100 pounds of fat to his hump. Then he can go several days without a drink. If he munches on dewy desert vegetation he can keep going for more than two waterless weeks. The record is 34 days. The camel's economical systems for storing food, water and energy are related to each other and very complicated.
As other animals lose moisture, water is lost from the blood stream and they soon become exhausted. The camel's huge drink goes not to his stomach, but spreads through the tissues of his entire body. This tissue water is used up in the thirsty desert, while his blood stream is left to provide oxygen as usual. He loses weight and his hump dwindles, but he remains active until the end.
Some biologists have suggested that the 100 pounds of fat in his hump could be converted into 30 gallons of water. But to perform this miracle, the camel would use so much extra oxygen that more than 13 gallons of moisture would be lost in the breathing process. Experts now agree that the fat in his hump is converted into the steady energy that keeps him trudging through the desert wasteland.
The amazing camel also has other built in conveniences to keep him going without food and water. He sweats very little and his thick, silken coat insulates his body from the worst of the desert heat. During the cool desert night, his body temperature drops and he usually remains com¬fortably cool until noon.
The camel's thick eyelashes and closeable nostrils protect him from sand storms. So, with his built in conservation systems of food, water and energy he should be quite comfortable in the desert. Nevertheless, he is a very grumpy, spiteful character, always ready to bite a human friend or spit in his face. Of the Arabian camel it is said that there are no wild ones but neither are there any tame ones.