Habitat
This is a montane species, attracted to rocky canyons, cliffs, and hillsides, including areas of oak woodland, thornscrub, and mixed oak and pine (Stebbins 2003). Typically it occurs on rocky outcrops, sometimes climbs trees.
Ecology
Aggregates in winter. On Mt. Graham, southeastern Arizona, a high-density population comprised 41 adults and juveniles (not including hatchlings) in a rock area of 495 sq m (Beuchat 1989). In southeastern Arizona, August home range size of adults averaged about 90-320 sq m, with the highest value in males at high elevations, and the lowest value in females at low elevations; female home ranges overlapped each other more so than did male home ranges; the ranges of multiple females overlapped with those of single males; the home ranges of juveniles were much smaller than those of adults (Ruby and Baird, 1994, J. Herpetol. 28:70-78).
Annual survival generally is 50% at most, often about 15-30%; populations may be reduced during periods of drought (Smith and Ballinger 1994).
Reproduction
In Arizona, mates September-October, gives birth in May-June at lower elevations, late June at 5000-7000 ft; litter size, which increases with female size, averages 7-11 (Goldberg 1971, Ruby and Dunham 1984, Beuchat 1989). Litter size averages 7 in north-central Mexico, with neonates observed in May (Ramirez-Bautista et al. 2002). May mature in 5 months at low elevations, 15 months at high elevations. Growth rate appears to be slowed when food resources are low (Smith and Ballinger, Copeia 1994:1007-1013).