A camel can travel hundreds of miles, over several days, without stopping to drink. On today's Moment of Science, we'll learn how camels survive the dry desert.
Let's start with the hump. Contrary to what you might have heard, camels do not store extra water here. The hump stores fat, providing energy for their long, desert trek. This fat, however, can help keep a camel from getting thirsty. As the fat is burned, water is produced as one of the byproducts. This extra water enters the camel's bloodstream to add to its water supply.
Camels conserve water by not sweating as much as we do. A camel's metabolism lowers at night, making its body temperature much lower than a human's. Because we sweat to cool ourselves off, starting with a lower body temperature means less need to sweat. Camels are also covered with heavy fur which keeps the daytime heat out. Because it's so good at keeping its cool, a camel can travel a long way without sweating very much.
Camels are also good at maintaining their blood volume. Once we humans lose about twelve percent of our body's water, our blood becomes too thick to work properly. A camel's blood, however, stays more or less consistent, allowing the camel to lose up to twenty-five percent of its weight by dehydration. Another thing that helps a camel conserve water is its nasal passages. When we exhale, we lose a lot of water vapor, as any fogged up car window will show. Camels have extra dry nasal passages which actually recondense the water out of each breath, allowing much less to escape.
As you can see, there is no single explanation for a camel's desert survival abilities. Instead, a camel draws on a whole range of adaptations.