Trans-Pecos copperhead, Agkistrodon contortrix pictigaster. Underside showing the distinctive pattern of this copperhead subspecies. The Trans-Pecos copperhead inhabits the Big Bend and Davis Mountans regions of southwest Texas, where it prefers the vicinity of desert springs, seeps, moist canyons and riverbank thickets. It is the smallest of the copperheads, averaging 20 - 30 inches in length. Its scientific subspecies name, "pictigaste", means "patterned belly", and refers to its checkered underside.