Visitors to Roxborough State Park often see mule deer, black-tailed prairie dog, coyote, cottontail rabbit, red fox and rock squirrel. Occasional observations of elk and black bear, and rare sightings of mountain lion and bobcat also occur. Eleven of the sixteen species of reptiles and amphibians that could be expected in the park based upon range and habitat information have been recorded at Roxborough. These include western rattlesnake, milk snake, snapping turtle, short-horned lizard, Woodhouse’s toad and western chorus frog. Over 50 species of butterflies, moths and skippers have been documented in the park.
Roxborough’s bird list is a compilation of over twenty years of bird observation and contains 145 species, 42 of which nest in the park. Raptors, songbirds, waterfowl and grassland species, such as vesper sparrow and western meadowlark occur in the park. Visitors often observe canyon wren, western tanager and broad-tailed hummingbird among other birds. Many sensitive species are present as well, such as ferruginous hawks and burrowing owls. A golden eagle nest is located on the Fountain Formation just outside of the park boundary.