The park has a decent amount of desert wildlife, though much of it is shy. Perhaps the most obvious creatures in the park are the lizards - several varieties exist, and they like to sun themselves on the park rocks. Snakes, including rattlesnakes, also inhabit the park.

Soaring through the skies and echoing their rough call off the canyon walls, ravens are one of the more visible birds in the park. More social (read: obnoxious) at the picnic areas are the scrub jays. In the winter, rosy finches and juncos flock through the park (if you want to see all the varieties of junco, this is the place...). In other seasons, the canyon wren supposedly sings here. Golden eagles also supposedly abound in the area (they even rate warning signs on the highways), though I have yet to see one in the entire state. Condors sometimes wander up from Arizona; you'll know if you see one - they've got white painted lettering on the wings...

Less obvious are the desert bighorn sheep, cougars, coyotes, foxes, and other mammals. The only mammals I see regularly in the park are chipmunks and ground squirrels. There were lots of sheep tracks along the Devil's Garden primitive trail when I was last there, and I saw some Mule Deer at Delicate Arch.

In addition to the rattlesnake, it is worth noting that the area is home to black widow spiders. Insects abound in Spring, pollinating the flowers, but are rare in other seasons.

Vegetation is typical for this area of the desert. Saltbush, sagebrush, rabbitbrush, pinon pine, and Utah juniper make up most of the "larger" plant life. Grasses, an assortment of desert wildflowers, and prickly pear cactus make up the undergrowth. A variety of lichens make interesting patterns across some of the rocks throughout the park.