The secrets of a camel's hump

My two-year old son loves exotic animals. Since we don't have too many of them roaming the streets of Berlin, I get to spend a lot of time at the Tierpark, one of Berlin's two zoos.

The zoo's grounds are extensive, and on the way to the animal houses, we pass various outdoor enclosures. Not surprisingly, as temperatures continued to drop over the winter, we saw fewer and fewer animals in them.

On one particularly chilly Sunday morning, it appeared as if all the animals had finally been moved inside. Except, to my surprise, the dromedaries. Why on earth were these desert creatures still outside in the freezing cold?

As it turns out, dealing with extreme temperatures is one of the great talents of the dromedary — and camels in general. 

For most mammals, maintaining core body temperature is paramount. A rise of more than 4 degrees Celsius (7.2 degrees Fahrenheit) would cause big problems for a human, for instance. But for a camel, it's quite normal to begin the morning with a body temperature of 34 degrees and heat up to 40 degrees by sunset with no fever involved.

Why is this ability useful? When it gets hot, we put a lot of energy and sweat into keeping cool. Sweating means losing moisture, something you want to avoid at all costs if, like most camels, you live in a desert.

So the camel lets its core temperature rise a bit instead. Once the sun sets, it can cool down again over night. 

Camels do sweat a little. But they mainly rely on their thick fur to guard against both cold and warm temperatures. Studies have shown that a shorn camel sweats up to 50 percent more in the heat. 

Fat not water

The camel's characteristic hump is also borne out of the imperative to keep cool. Contrary to common belief, the humps don't store water but fat.

So why not store that fat all around the body like most other mammals do?

If they did so, it would serve as extra insulation and keep them warm. That's great when you're a polar bear or a bison in the Arctic, but not helpful in the desert heat. So camels carry their fat on their backs.

To be fair, there is something to the myth of water in their humps. Sort of. While they don't actually contain water, the camels can convert stored fat into water. In fact, they are so efficient at doing this, they can turn a gram of fat into more than a gram of water.

Storing and retaining water is probably the camel's biggest claim to fame. Rightfully so, even if they don't do it the way most people think they do. 

They are so good at retaining moisture that their urine has the consistency of syrup. They can go without a drink for up to 10 days, even when it's very hot. And if necessary, they can drink water saltier than the sea.

When they do get a chance to quench their thirst, a large camel can down as much as 200 liters (53 gallons) in just three minutes.

Cheers!