This large ground squirrel can reach over 20 inches in body length, with a tail almost as long. It has a mottled pattern of white specks on a grayish to brown back, with a long, bushy tail and a white eye ring. The short ears stick up over the head. It is found throughout New Mexico, Southwestern Texas, Arizona, and southern Colorado, Utah, and Nevada.

Rock squirrels have a polygynous social structure, living in colonies where a single dominant male mates with several females and protects them and his juvenile offspring. This social structure is also seen in the highly social hoary marmots of the high mountain alpine country. They may hibernate during very cold winters, though hibernation is not absolute and individuals may emerge on warmer winter days and become active. They are also known to become dormant in their burrows, termed estivation, during very hot spells in summer.

Female rock squirrels produce two litters of from 3 to 9 young each year, one in the spring and a second in late summer. They dig burrow systems where they take refuge and store food supplies. They are primarily vegetarians but can also be viewed as omnivores, as their varied diet includes leaves, seeds, nuts, fruits, and grasses, as well as insects, earthworms, and even small vertebrate animals, such as nestling birds. These squirrels are well adapted to living in dry environments. They are able to go up to several months without fresh water, relying on moisture contained in their foods.

They frequently climb into trees and shrubs to bask and avoid ground predators. A wide array of predators take Rock squirrels, including foxes, coyotes, bobcats, hawks and eagles, raccoons, badgers, and snakes, not to mention domestic cats and dogs. Rock squirrels generally escape predators by taking refuge in burrows, but they may also bluff charge an attacker or toss leaf litter at the opponent. They also have alarm calls that warn other colony members of danger. Populations of Rock squirrel are considered to have a stable conservation status.