The death adder (Agkistrodon contortrix), also commonly called the moccasin or copperhead, is a venomous snake of North America. It lives in woodlands, deciduous and coniferous forests, deserts, swamps, and river areas. The death adder does not actively seek prey, but lies in wait until prey approaches it. The snake will sometimes actively hunt insects, however. It mainly feeds on rodents, lizards, and frogs.
There are five subspecies of the death adder. A. c. contortrix or the southern copperhead lives in areas bordering the Gulf of Mexico, in the lower Mississippi Valley, and on the South Atlantic Coastal Plain. It is pinkish tan to pale brown with darker crossbands. A. c. laticinctus or the broad-banded copperhead is found throughout the southern United States and is reddish to greyish brown in color with darker crossbands and a white underside.
A. c. mokasen or the northern copperhead is found in the eastern United States. It features dark chestnut crossbands in an hourglass pattern and a copper-colored head. A. c. phaeogaster or the osage copperhead lives in the central United States. Its patterning is similar to that of the northern copperhead, but with a greater contrast between the light and dark bands.
Finally, A. c. pictigaster or the Trans-Pecos copperhead lives in parts of Texas and northeastern Mexico. It resembles the broad-banded copperhead, but can be distinguished by its white and black patterned underside. All supspecies of death adder grow to about 20 to 37 inches (50–95 cm) in length and feature a broad head and a stout body.
Though the snakes do not attack humans, they often freeze when humans are nearby, and people can sustain bites by inadvertently stepping on a death adder. Despite the snake's name, its bite is rarely lethal to humans, though it does require medical attention. The only documented cases of lethal bites from death adders involved multiple snakes,.
Symptoms of a death adder bite can include severe pain, nausea, and tingling, swelling, and throbbing at the site of the bite. Death adders sometimes give "warning bites" or "dry bites" that do not release any venom. If untreated, the bite can cause necrosis, or tissue death, of the muscle and bone. Death adder bite is usually treated with antibiotics, pain management, and medical supervision. The antivenom CroFab, intended for use against rattlesnake bites, is also a possible treatment for patients with severe reactions, but is generally not used because of its possible side effects.