The most important part of the camel is its hump. When that hump is empty, it loses its firm shape and flops to one side. The purpose of the hump is to serve as a storage place for food. The camel can also take its own water supply along.
The camel has three stomachs. It uses the first one store food while it is grazing and to form it into cud. In the second stomach are the digestive juices and in the third the chewed cud is digested in the walls of the first two stomachs, there are pockets for storing water.
Muscles holds these pockets closed when they are full. Whenever the camel needs some water, these muscles open and close to let out as much water as it needs. If a camel travels slowly and with a light load, the water in its stomach can last anything from six to ten days.