Agkistrodon contortrix

Copperheads are often in or near deciduous forest in hilly situations, usually in the vicinity of rock outcrops; they occur also on floodplains and at edges of swamps in the south and in mesic situations near water in the arid west. Hibernation generally occurs in dens among rocks, or in caves, animal burrows, under objects, in hollow logs or stumps, or in similar sites. Usually copperheads area in areas with abundant surface cover such as rocks, logs, stumps, or leaf litter. They are mainly terrestrial but sometimes climb into vegetation up to a few meters above ground. In the east at least, gravid females select rocky areas that are more open and have warmer soil temperatures than those used by nongravid individuals (Reinert, cited by Ernst 1992).

Hibernates communally (especially in north) or singly. In Kansas, population density in fall was estimated at about 13/ha, with perhaps 2-4 times this many under optimal conditions; home range size was about 10 ha for males and 3.4 ha for females (Fitch 1960).

Most copulations occur in spring and late summer-early fall. Births occur mainly in August or September in most areas, but may occur as early as July or as late as November in some areas. In Kansas, individual females evidently give birth usually in alternate years, July-early October; males sexually mature in 2nd summer, most females in 3 years (Fitch 1960). In southern Texas, individual females may produce young in consecutive years (Vermersch and Kuntz, 1986, Snakes of south central Texas, Eakin Press, Austin). Litter size up to 21 (most often 4-8) in east and north, average of 5.3 in Kansas, usually not more than 3-4 in Trans-Pecos subspecies PICTIGASTER.