From extreme southwestern New Mexico and southeastern Arizona southward through Durango and Zacatecas.
Only found in mountainous areas like cliffs, rocky canyons, and hillsides. Terrain can be oak woodland, mixed oak and pine, and thornscrub. Occasionally climbs trees.
Snout-vent length can range up to 105 mm. Displays a thick black stripe around neck mimicking a collar that is bordered by a thin, white stripe. Dorsum is either gray or olive colored. Venter can be whitish or gray. Scales are large and keeled. Tail scales appear bigger than scales on rest of body. Males and females mate in the fall; females live-bear young in late June.
Learn more with Schechter Natural History's Guide to Reptiles and Amphibians