As Schwartz points out, the metabolic processes of the body all have outputs which often occur in the form of mineral build up. “Animals that live in an environment where water is readily available will just [get rid of those minerals] through their urine,” he says. “When you have animals that live in these extreme environments where they don’t want to excrete any fluids, the body will find other ways to get rid of those minerals.” The greater roadrunner of North America, which like the Dorcas gazelle can survive its whole life without drinking water, has developed a unique way of dealing with this problem: it secretes excess salt from a gland near its eye.