Agkistrodon contortrix
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| Agkistrodon contortrix Linnaeus, 1766 |
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Common names: copperhead (snake), chunk head, death adder, (dry-land) moccasin,[2] more.
Agkistrodon contortrix is a venomous pit viper species found in North America. Five subspecies are currently recognized, including the typical form described here.[3]
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[edit] Description
Adult specimens have a coppery colored head and neck. They are not large snakes, generally about 50 cm long (1.5 ft), but specimens up to 1 m long (3 ft) have been encountered. The body is slender compared to most other pit vipers. There are five clearly defined subspecies. All subspecies have distinctive light and dark brown or greenish banding. A. c. mokasen, A. c. contortrix and A. c. phaeogaster have bands that tend to narrow dorsally, giving them an hourglass shape, whereas A. c. laticinctus and A. c. pictigaster generally have bands of uniform width. Intergrading occurs in areas where the subspecies geographic ranges overlap, so pattern variations are commonplace. A. c. pictigaster is known especially for its distinctively patterned underside, with white and black banding.
[edit] Common names
Copperhead (snake), chunk head, death adder, (dry-land) moccasin, narrow-banded copperhead, northern copperhead, pilot snake, poplar leaf, red oak, red snake, southeastern copperhead, white oak snake,[2] cantil cobrizo (Spanish).[3]
[edit] Geographic range
Found in the United States (Texas, Oklahoma, Kansas, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Tennessee, Kentucky, Virginia, West Virginia, Illinois, Indiana, Ohio, Iowa, Pennsylvania, Maryland, New Jersey, Delaware, New York, Connecticut, Massachusetts), Mexico (Chihuahua, Coahuila). The type locality is "Carolina." Schmidt (1953) proposed that the type locality be restricted to "Charleston, South Carolina."[1]
[edit] Behavior
Like all pit vipers, A. contortrix is an ambush predator: it takes up a promising position and waits for suitable prey to arrive. Roughly 90% of its diet consists of small rodents, such as mice and voles.
[edit] Reproduction
A. contortrix breeds in late summer, but not every year: sometimes a female will 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 one or as many as 20. Their size apart, 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.
[edit] Venom
A. contortrix is venomous, but almost never deadly to humans and are generally non-aggressive. 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. The genus name Agkistrodon is derived from the Greek agkistron (fish-hook) and odon (tooth); a reference to the curved fangs. The primary role of the venom and fangs is to kill their food items quickly; the amount of venom a single copperhead can deliver is insufficient to kill an otherwise healthy adult human. It is capable of, however, producing intense pain, tingling, throbbing, swelling, and severe nausea. While rarely lethal, a copperhead bite can be damaging to muscle and bone tissue, especially when the bite occurs in the outer extremities such as the hands and feet, areas in which there is not a large muscle mass to absorb the venom. A bite from any venomous snake should be taken very seriously and immediate medical attention sought.
In the state of Missouri about 200 people suffer from snakebite each year, mostly from copperheads, but there are no records of deaths resulting.[citation needed] Although, technically the antivenom CroFab could be used to treat an envenomation from a copperhead, it is not typically administered as the risk of complications through an allergic reaction to the treatment is greater than the risk from the snakebite itself. Pain management, antibiotics, and medical supervision in the case of complications is typically the course of action.[1]
[edit] Frequency of Encounters
Commonly, the average person will assume any reddish or brownish snake is a copperhead. This is far from the case. Many harmless snakes, such as the brown snake (genus Storeria), or water snake (genus Nerodia) are frequently mistaken for copperheads. Copperheads are primarily a terrestrial species, and though quite capable swimmers, they are rarely found swimming.
The easiest way to tell venomous snakes from non-venomous in North America is by the shape of their pupils. All dangerously venomous snakes in North America, with the exception of the coral snake, are pit vipers and have a vertical type pupil, like a cat's eye. Most non-venomous snakes in North America have a round pupil like a human. However, some harmless, nocturnal Colubrids have vertical elliptical pupils.
[edit] Safety
The best way to avoid being bitten when in the outdoors in copperhead country 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, given the opportunity, will leave the area without biting; however, unlike the rattlesnake, they are unable to make an audible warning of their presence.
Copperheads often tend to "freeze" instead of slithering away; thus, many bites come from people unknowingly stepping on or near them. This tendency to freeze likely evolved because of the extreme effectiveness of their camouflage. When lying on dead leaves or red clay they can be almost impossible to notice. They will frequently stay still even when approached closely, and will generally strike only if physically harassed or trod upon.
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. In the south, copperheads are nocturnal during the hot summer months, but are commonly active during the day during the spring and fall. 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 or attacking it with an object.
If bitten, one should not apply a tourniquet or suck blood from the bite — the victim should be kept calm and be transported to a hospital as quickly as possible. A tourniquet will increase tissue damage in the area of the bite and may even create the need to amputate a bitten limb that may have otherwise been saved. Never cut where the bite is.
[edit] Subspecies
| Subspecies | Authority | Common name | Geographic range |
|---|---|---|---|
| A. c. contortrix | (Linnaeus, 1766) | Southern copperhead | South-eastern United States |
| A. c. laticinctus | Gloyd & Conant, 1934 | Broad-banded copperhead | Kansas, Oklahoma and Texas |
| A. c. mokasen | Palisot de Beauvois, 1799 | Northern copperhead | Northeastern United States |
| A. c. phaeogaster | Gloyd, 1969 | Osage copperhead | Mid-western United States |
| A. c. pictigaster | Gloyd & Conant, 1943 | Trans-pecos copperhead |
[edit] See also
[edit] Gallery
 Broad-banded copperhead |
 Southern Copperhead |
 Copperhead crossing river in Virginia Beach |
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 Southern Copperhead in Covington, Georgia, at Bert Adams Scout Reservation. |
[edit] Cited references
- ^ a b McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- ^ a b Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. ISBN 0801404630 .
- ^ a b Agkistrodon contortrix (TSN 174296). Integrated Taxonomic Information System. Accessed on 28 November 2006.
[edit] External links
- Species Agkistrodon contortrix at the Species2000 Database
- Reclining With Vipers - suburban hiker gets up close and personal with northern copperheads
