Camels can go up to seven months in the desert without drinking water. During such a time, they may lose nearly half of their body weight. But do their humps get smaller?

Even a really thirsty camel might still have a hump – as long as it’s not really hungry, too.

Camels store fat in their humps, not water. As a camel goes without food, its hump begins to shrink. If it stays hungry long enough, its hump will disappear.

So if the camel doesn’t store water in its hump, where does it store water?

Until recently, many scientists believed that camels could store water in one of their three stomachs. Very thirsty camels can drink up to 100 liters of water during a single visit to the well. There’s no evidence, though, that camels can store water for long periods of time anywhere in their bodies.

Camels are just very efficient at using water, and they’re well-adapted for dehydration. The camel seems to be designed – both inside and out – to hold on to whatever water it takes in. Its fur prevents the camel from sweating too much. Its blood cells are also tiny enough to keep circulating as the camel’s blood thickens from dehydration – but elastic enough to hold lots of water. If a thirsty camel finds an oasis, its red blood cells might balloon to more than twice their size – while its hump remains unchanged.