how do desert animals retain and acquire water in such a hot and dry environment?

Desert animals/plants are adapted in special ways to live in dry hot environments. They stay as cool as possible by finding shade and going underground. They get their water from the food they eat such a green leaves (Which contain alot of water) and from the fluids of the animals they prey on. As example : Rodent rats are able to make water inside their bodies while digesting their food.