The roadrunner gets its moisture largely from its omnivorous diet, which includes lizards and small rattlesnakes. The kangaroo rat metabolizes both energy and moisture from seeds that contain less than 4 percent water. It has no sweat glands and cools itself mostly by breathing. Its nasal passages condense breath moisture for retention. Its kidneys, among the most efficient in the animal world, excrete uric wastes as a concentrated paste rather than as a liquid, saving further previous water.
Many animals survive life in the desert by coming out only at night.
Most snakes do this because summer daytime temperatures on the desert floor would kill them within minutes. Some of the park's lizards, though, brave the daytime heat to do their hunting. Most often seen is the western whiptail. The greenish collared lizard may be seen racing along on his hind legs like a miniature dinosaur. Lizards are about the biggest ground dwellers you scare up on a noonday walk, unless you happen upon a lizard-eater like the big, pink western coachwhip snake.