Eastern copperhead

The eastern copperhead (Agkistrodon contortrix), also known simply as the copperhead, is a widespread species of venomous snake, a pit viper, endemic to eastern North America; it is a member of the subfamily Crotalinae in the family Viperidae.

The eastern copperhead has distinctive, dark brown, hourglass-shaped markings, overlaid on a light reddish brown or brown/gray background. The body type is heavy, rather than slender. Neonates are born with green or yellow tail tips, which progress to a darker brown or black within one year. Adults grow to a typical length (including tail) of 50–95 cm (20–37 in).

In most of North America, the eastern copperhead favors deciduous forest and mixed woodlands. It may occupy rock outcroppings and ledges, but is also found in low-lying, swampy regions. During the winter, it hibernates in dens or limestone crevices, often together with timber rattlesnakes and black rat snakes. The eastern copperhead is known to feed on a wide variety of prey, including invertebrates (primarily arthropods) and vertebrates. Like most pit vipers, the eastern copperhead is generally an ambush predator; it takes up a promising position and waits for suitable prey to arrive.

As a common species within its range, it may be encountered by humans. Unlike other viperids, it often "freezes" instead of slithering away and fleeing, due to its habit of relying on excellent camouflage. Bites occur due to people unknowingly stepping on or near them. Copperhead bites account for half of the treated snake bites in the United States.

Five subspecies have been recognized in the past, but recent genetic analysis has yielded new species information.