Camels do not store water in their humps. Instead, camels use the humps to store energy-rich fat deposits. Many animals, including humans, use body fat as an energy storage. Unique to a camel, however, is the fact that it stores the fat in a hump up on top instead of around the belly or limbs. It does this to stay cool. Fat has a natural tendency to insulate heat, acting like a blanket to bodies that are covered in fat. Being a hot-climate animal, a camel would waste energy trying to cool down if its fat were wrapped around its body. Instead, by placing the fat in a hump that is out of the way, the camel can stay as cool as possible while still having an energy reserve. Think of it like a tourist from northern Siberia with a coat stuffed full of snacks just stepping off the plane in the Sahara Desert. What does he immediately do? He takes off his coat and slings it over his shoulder. He still wants to lug around his coat full of snacks, he just does not want it wrapped around him making him hot