Habitat
Habitat includes rocky areas (rock slides, outcrops, canyon slopes, areas near cliff, stream courses), with vegetation ranging from arid tropical scrub, tropical deciduous forest, mixed boreal-tropical forest, paloverde-cactus-thornbush associations, oak-grass savanna, and mesquite grasslands to chaparral and the pine-oak and pine-fir belts (Werler and Dixon 2000, Ernst and Ernst 2003, Stebbins 2003, Campbell and Lamar 2004). In Arizona and northern Mexico, this snake often occurs in rocky areas in pine-oak association. A population in southeastern Arizona frequented rocky areas but used arroyos and creosotebush flats in late summer and fall (Beck 1995). Other habitats include creosotebush-covered hills, grassy prairie, giant-dagger flats, and the vicinity of abandoned buildings (Tennant 1984). This species occupies wide range of habitats in Mexico, where at the southern end of the range habitats include pine-oak, oak savanna, sweet-gum/oak forest, and mesquite grassland (Armstrong and Murphy 1979). Refuges during inactivity include rock crevices, caves, animal burrows, or wood rat houses. This snake is mostly terrestrial but sometimes climbs into trees or bushes.
Ecology
In southeastern Arizona, mean home range size was 3.49 ha, and individuals moved an average of 43 m per day during the active season (Beck 1995). In the same region, Hardy and Greene (1999) reported very small home range sizes but mentioned moves of up to 1.5 km. Distance per move for one individual in New Mexico averaged less than 25 m, distance moved per day average less than 13 m, and daily activity areas averaged 716 sq m or less; annual home range size was not reported (Smith et al. 2001).
Reproduction
Gives birth to litter of usually about 3-8 young (up to 16), in late July in Texas (Tennant 1984), probably also in August in northern range. Male may remain with female after mating (Greene, cited by Ernst 1992).