Central United States and Mexico; southeastern Arizona, New Mexico, southeastern Colorado, northern Texas, and San Luis Potosi.
Found in a variety of habitats including desert grassland and desert shrubland in areas with little vegetation. Prefers rocky soils near washes, desert flats, bajada slopes, and arid and semiarid hills. Burrows in rodent burrows while inactive and to lay eggs.
Dorsum usually reflects the color of ground in habitat; usually gray but can be light brown or pale yellow. Tail, neck, and groin usually display darker colors than rest of body. Body flat and round with small head exhibiting crest of horns. When camouflaging, resemble a rock. Females and males breed in June or July and eggs hatch from July to August. Clutch sizes range from 9-18 eggs.
Learn more with Schechter Natural History's Guide to Reptiles and Amphibians