Ostospermophilus variegatus

Rock Squirrel

Family: Sciuridae · Class: Mammalia · Order: Rodentia

The rock squirrel (Otospermophilus variegatus) is a medium-sized ground squirrel native to the southwestern United States and northwestern Mexico. Adults measure 430-540 mm (17-21 inches) in total length, with a body length of 240-290 mm (9.4-11.4 inches) and a tail comprising roughly half the total length. Weight ranges from 450-875 grams (1-1.9 pounds), with males typically larger than females. The pelage is highly variable, ranging from gray-brown to nearly black on the dorsal surface, with lighter underparts. The tail is bushy and often darker than the body, with white-tipped guard hairs creating a grizzled appearance. Rock squirrels occur throughout much of the southwestern United States, from Colorado and Utah south through Arizona, New Mexico, and western Texas, extending into northwestern Mexico. In California, the species has a limited distribution, primarily occurring in the southeastern desert regions of the state, including portions of San Bernardino and Riverside counties. The species inhabits elevations from sea level to approximately 2,800 meters (9,200 feet). This species shows strong habitat associations with rocky terrain, including canyon walls, boulder fields, cliff faces, and rocky outcrops. According to Animal Diversity Web, rock squirrels are most closely associated with upland grasslands and oak savanna environments that provide rocky shelter sites. The species also utilizes desert shrubland habitats with scattered rocks and boulders for denning and escape cover. Burrow systems are typically excavated beneath large rocks or in rock crevices, providing protection from predators and temperature extremes. Rock squirrels are omnivorous, with diet varying seasonally and geographically. According to NatureServe, they feed on a wide variety of plant material including nuts, seeds, grain, berries, roots, green vegetation, and cactus, as well as invertebrates and both fresh and dried meat. The species is active during daylight hours, with peak activity occurring in early morning and late afternoon. Rock squirrels are semi-social, often living in loose colonies where suitable habitat allows. Breeding occurs once annually, typically from March through June, with females producing litters of 3-9 young after a gestation period of approximately 30 days. Young become independent at 6-8 weeks of age. The rock squirrel is classified as Least Concern by the International Union for Conservation of Nature, reflecting stable populations across most of its range. According to Idaho Department of Fish and Game, the species has a Global Conservation Rank of G5, indicating it is secure globally. However, in California, the species occurs at the periphery of its range and may face localized pressures from habitat modification and urban development in desert regions. The species' dependence on rocky habitat features makes it potentially vulnerable to quarrying operations and recreational rock climbing activities in some areas. Climate change may also affect the species through altered precipitation patterns and increased temperatures in already arid habitats.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.