Camels are special animals. They can survive in the desert without water and food for months.
But is it really because of the camel's hump that stores water?
The answer is not 100% correct. While camels have tricks to make the most of the water, their hump isn't one of them. So why do camels have humps on their backs? The answer is as a "chamber" fat storage.
"They face a drought when food and water are scarce," said Rick Schwartz, animal care supervisor and national spokesperson at the San Diego Zoo.
When food is available, camels eat enough calories to build their hump so they can last a long time when food is scarce. "With a "full" hump, a camel can last up to four or even five months without food, says Schwartz.
When camels use up their fat, their empty hump will fall like a deflated balloon until they have eaten enough to "inflate" again.
Camels themselves are not born with this fat deposition and do not grow while they are breastfeeding. "All the energy they get from the mother will be used for the growth of the body," Schwartz told Live Science.
Young camels start weaning when they are 4 to 6 months old, although the hump doesn't begin to form until they are 10 months to a year old. "But because wild camels deal with cyclical seasons, they need to have some sort of hump in that first year," explains Schwartz. "They have to go through that first dry season."
In the world, there are two species of camels. The Bactrian camel (Camelus bactrianus) lives in parts of western China and Central Asia, and they have two humps. While the Arabian camel (Camelus dromedarius) is more common and has only one. But as far as Schwartz is concerned, the extra mound doesn't allow the Bactrian camel to go much longer without food.
Although many animals store fat around the belly and sides, camels accumulate weight vertically.
"One theory is that camels have calloused bellies that they put directly in the sand, and belly fat can make it more difficult to lie down this way," Schwartz said.
Another theory is that being tall and narrow, with fat stored in the hump instead of around the sides, means the camel is exposed to less sun and less heat. Since the camel's hump stores food, dromedaries need another way to deal with water scarcity.
For example, camels can drink up to 30 gallons (114 liters) of water in a single meal, they excrete dry feces to retain water, and their kidneys efficiently remove toxins from the water in their bodies so they can retain as much of it as possible. Camels have a few other ways to make every drink of water go a long way.
For example, by capturing moisture from every breath they exhale through the nose.
"This extraordinary ability to live on less water may be the reason why there is a myth that if they lived so long without water, they must have stored water in the hump," Schwartz said.