Types of Pit Viper Snakes in the American Southwest

The Southwestern Center for Herpetological Research (SWCHR) defines the American Southwest as the states of California, Nevada, Arizona, New Mexico and Texas. Several species of pit viper snakes inhabit these states. According to Brian Thomas, science writer for the Institute for Creation Research, pit vipers are distinct in that they have heat-sensing nerve cells in two "pits" located between their nose and eyes. These pit sensors enable them to find their prey without using sight.

  1. Copperheads (Agkistrodon contortrix)

    • Southern, Broad-Banded, Trans-Pecos and Western Copperheads are all pit vipers that make their home in the American Southwest. Copperheads, named as such for their characteristic copper-colored heads, can reach lengths of up to 30 inches. The rest of their bodies have an alternating reddish-brown and copper pattern. A copperhead's fangs grow and shed, and are replaced periodically throughout its lifetime, which is approximately 18 years; therefore, a longer snake will generally have longer fangs. Copperheads' venom is seldom life-threatening to humans, but bites can cause a number of potentially serious symptoms, such as nausea, vomiting, breathlessness, fatigue, pain and swelling in the bite area, and occasionally loss of consciousness.

    Water Moccasins (Agkistrodon piscivorus)

    • The water moccasin, also called the cottonmouth for its distinctly bright white mouth, can reach lengths between 30 to 42 inches. Most species of water moccasin are distributed throughout the southeastern United States; only a select few species, such as the western water moccasin, are found in the American Southwest. Water moccasins can vary in color depending on the species; some have tan and reddish banding, and older snakes may have solid dark brown or black banding. Although not fatal, the bite from a water moccasin can be exceedingly painful, and will cause tissue damage and persistent bleeding; immediate medical attention is advised.

    Rattlesnakes (Crotalus)

    • According to the University of Texas Amphibian and Reptile Diversity Research Center, rattlesnakes are one of the most prevalent pit vipers in the United States today, with approximately 28 species residing in the American Southwest alone. All rattlesnakes are considered pit vipers because they seek their prey using thermal glands. Some rattlesnakes, such as the diamondback, can reach lengths of up to eight feet; on average, however, most rattlesnakes are between three to four feet in length when fully grown. Rattlesnakes use communal dens, which they return to yearly during the winter months. Rattlesnakes come in a variety of colors and patterns depending on the species. For instance, the red diamond rattlesnake can have a reddish-brown or tan pattern, and a southwestern speckled rattlesnake can be gray or tan with white and black speckles.