The broad vistas of desert landscapes can distract the visitor's eyes from the small and quick near at hand. Despite the impression that the desert is lifeless, many animals make their homes in deserts. Birds, lizards, and ground squirrels are most likely to be seen because they are largely active during the day. However, it is at night that desert animals come out to roam. Mostly nocturnal animals include: snakes, bighorn sheep, kangaroo rats, coyotes, and black-tailed jack rabbits. Dusk and dawn are good times for viewing many kinds of animals, both those just going to bed and those just getting up. Animals that thrive in desert environments often have special adaptations for dealing with limited water and high summer temperatures.
One does not walk far in the desert without seeing a multitude of burrow openings. The smaller mammals and all reptiles take refuge from the heat underground. Reptiles are physiologically adapted to getting along with much less water than mammals and birds can fly to water. And desert mammals make more efficient use of their bodies' water supply than does the human body. Nevertheless, the springs and seeps in the park are necessary to the survival of many animals. Most of the reptiles and many small rodents and insects go into an inactive state of hibernation during the winter. However, winter is the time of greatest bird concentrations in the park, because of the presence of many migrant species.