A type of rat can survive longer without water longer than a camel can.
The kangaroo rat is able to survive in the desert with virtually no drinking water. How? Its kidneys produce the most concentrated urine of all mammals, and only pass a few drops per day.
Humans drink a lot of water, and also gain moisture through food. As such, our urine is quite dilute. Kangaroo rats, on the other hand, take in very little water and so produce urine that is even more concentrated than that of the camel. This means that the kangaroo rat loses little water in its urine.