Common names: Trans-Pecos Copperhead.

Agkistrodon contortrix pictigaster is a venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 pitviper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 found in the Trans-Pecos

Trans-Pecos

The term Trans-Pecos, as originally defined in 1887 by the Texas geologist Robert T. Hill, refers to the portion of Texas that lies west of the Pecos River. The term is considered synonymous with "Far West Texas", a subdivision of West Texas...

 region of the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, in western Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, and northeastern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.

Description

This subspecies is typically a light tan in color, with darker brown, wide crossbands. Their actual color varies by locality, varying from a red-brown, to a gray-brown. The species can be difficult to distinguish from the Broad-banded Copperhead, A. c. laticinctus

Agkistrodon contortrix laticinctus

Agkistrodon contortrix laticinctus is a venomous pitviper subspecies found in the southern United States, from Kansas, through Oklahoma and throughout central Texas.-Description:...

. The only notable physical difference between the subspecies is that the Trans-Pecos Copperhead tends to have an elaboratedly patterned underside, often being an irregular, white and black pattern whereas the Broad-banded tends to be plain white, only have minimal patterning, or have elongated random blotching instead of a distinct pattern. The subspecies intergrade where their ranges overlap, further confusing identification. It is easily distinguished from other subspecies of copperhead, in that other species typically have banding that narrows at the spine, creating hourglass

Hourglass

An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically...

 shapes, whereas A. c. pictigaster has bands that do not narrow at the spine. They grow to approximately 20-36 inches (50-90cm)in length. As juveniles, all species of Agkistrodon

Agkistrodon

Agkistrodon is a genus of venomous pit vipers found in North America from the United States south to northern Costa Rica. The name is derived from the Greek words ἄγκιστρον 'fishhook' and ὁδοὐς 'tooth', and is likely a reference to the fangs...

 have a bright green-yellow color to their tail

Tail

The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...

 tip believed to be used as a lure to attract prey items to approach within striking range. The color fades to a grey or brown at about a year of age.

Behavior

Like all A. contortrix subspecies, A. c. pictigaster is a nocturnal ambush predator

Predation

In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

. Their diet

Diet (nutrition)

In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

 consists of primarily lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s, frog

Frog

Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s, and rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s. Their choice of habitat is the driest among the copperhead subspecies, preferring rocky, lightly vegetated, canyon areas. They are ovoviviparous

Ovoviviparity

Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...

, giving birth to a litter of up to 8 young in the early fall.

Venom

Like most pit viper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 species, A. contortrix has a hemotoxic

Hemotoxin

Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells , disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term hemotoxin is to some degree a misnomer since toxins that damage the blood also damage other tissues...

 venom, which is delivered through hinged, hollow fangs set in the front of their jaw. The fangs work like hypodermic needle

Hypodermic needle

A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...

s, injecting the venom in a single, quick striking motion. Copperhead venom is not considered to be life threatening to an otherwise healthy adult, but it can cause localized swelling, necrosis

Necrosis

Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

, and severe pain. Any bite from a venomous snake should be considered serious and medical treatment sought. There is no antivenin

Antivenin

Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...

 specifically manufactured for copperheads, but CroFab

CroFab

CroFab is the commercial name for a Crotalidae Polyvalent Immune Fab snake antivenom, indicated for minimal or moderate North American Crotalid snake envenomation. It is developed and manufactured by BTG plc , and distributed in the US by Nycomed Inc...

, which makes use of the venom from the cottonmouth (Agkistrodon piscivorus

Agkistrodon piscivorus

Agkistrodon piscivorus is a venomous snake, a species of pit viper, found in the southeastern United States. Adults are large and capable of delivering a painful and potentially fatal bite. When antagonized they will stand their ground by coiling their bodies and displaying their fangs...

), can be used in cases of a severe envenomation.

External links

• Agkistrodon contortrix at University of Texas. Accessed 7 December 2007.
• Trans-Pecos Copperhead at WhoZoo. Accessed 7 December 2007.