The American copperhead (Agkistrodon contortrix) is a species of venomous viper native to eastern North America. Mature copperheads have a beautiful coppery colored head and neck. They tend to be smallish snakes, generally about 1.5 ft long (50 cm), but specimens up to 3 ft long (1 m) have been encountered. The body is thin by pit viper standards. There are four clearly defined subspecies.
- The Northern copperhead (Agkistrodon contortrix mokasen) is found throughout the northeastern United States It is reddish brown overall, with a number of chestnut-colored “hourglass” markings running down its back.
- The Southern copperhead (A. contortrix contortrix) of the south-eastern United States is generally paler and has more clearly defined markings, sometimes including a row of dark triangular marks
- The Broad-banded copperhead (A. contortrix laticinctus) of Kansas, Oklahoma and Texas is sometimes considered the most attractive of the four. It tends to be smaller than the Northern and Southern races, rarely being longer than about 75 cm, and has wide bands across the back that are not narrowed at the spine.
- The Trans-Pecos copperhead (A. contortrix pictigaster) is similar to the Broad-banded, is of equal size, and has slightly hourglass-shaped markings, usually with a lighter patch at the base of each band.
The genus Agkistrodon, of which the American copperhead is a member, includes 10 species, three of them native to North America (one being the well-known Cottonmouth. The rest can be found in Asia and the islands nearby – notable members include the Siberian moccasin, the Himalayan viper, and the Okinawan habu. Note that the three Australian copperheads are elapids and not related.
American copperheads breed in late summer but not to a fixed pattern: sometimes a female will give produce young for several years running, then not breed at all for a time. They give birth to live young about 20 cm long: a typical litter is 4 to 7, but it can be as few as 1 or as many as 20. Other than size, the young are similar to the adults, but lighter in color, and with a yellow-marked tip to the tail, which is used to lure lizards and frogs.
Like all pit vipers, American copperheads are ambush predators: they take up a promising position and wait for suitable prey to arrive. Roughly 90% of their diet is small rodents: mice, voles, and similar creatures.
American copperheads are venomous but almost never deadly to humans. In fact, American Copperheads may have the distinction of being the “least venomous, venomous” land snake in the world. They have an efficient venom delivery system, with long fangs mounted at the front of the jaw which swivel back to allow the snake to close its mouth, but their primary role is to kill mice quickly: the amount of venom a single American copperhead can deliver is insufficient to kill a healthy adult human. It does, however, produce immediate and intense pain, followed by tingling, throbbing, swelling and severe nausea. While rarely lethal, a copperhead bite can be very damaging to muscle and bone tissue, especially when the bite occurs on the hands and feet, areas in which there is not a large muscle mass to absorb the venom.
The genus name Agkistrodon is derived from the Greek agkistron (fish-hook) and odon (tooth); a reference to the curved fangs.
In the state of Missouri, about 200 people suffer from snakebites each year, mostly from copperheads, but there are no records of deaths resulting. Although an antivenom exists, it is not usually administered as the risk of a death through an allergic reaction to the treatment is greater than the risk of the snakebite itself.
The best way to avoid being bitten is to be aware of their typical behavior and habitats and take appropriate precautions. Like most North American vipers, copperheads prefer to avoid humans and will leave the area without biting when given the opportunity. However, unlike rattlesnakes, they cannot make a loud noise to warn of their presence. They are said by some to smell like cucumbers, but that cannot be relied upon. In the South, copperheads are nocturnal during the hot summer months, but are commonly active during the day during the spring and fall.
Small hiding places such as niches in rock walls, woodpiles, etc., should be examined before hands or feet are placed in them, and one should stand on or bend over a fallen log to look for a snake instead of blindly jumping over. Favorite habitats include rocky hillsides above wooded streams. A pair of stout leather hiking boots might blunt the strike of a snake. Heavy tramping of feet will cause vibrations in the ground that can alert snakes to peoples’ presence, giving them time to quietly escape. The majority of snakebite incidents are the result of attempting to handle the snake.
If bitten, one should not apply a tourniquet or cut gashes or suck blood – the victim should be kept calm and be transported to a hospital as quickly as possible.