The United States is home to a variety of snake species, some of which possess venom. Understanding these snakes is important for public safety, particularly for individuals who spend time outdoors. Awareness helps in recognizing their presence and knowing how to react responsibly, which minimizes risks and promotes coexistence.
Understanding Venomous Snakes in the USA
Venomous snakes in the United States primarily fall into two major families: pit vipers and coral snakes. Pit vipers are the most common group, including rattlesnakes, copperheads, and cottonmouths (also known as water moccasins). They are characterized by a heat-sensing pit located between their eye and nostril, which helps them detect warm-blooded prey. Pit vipers also possess triangular-shaped heads and vertical, elliptical pupils, resembling a cat’s eye.
Coral snakes belong to a different family and are known for their distinctive bright coloration. Unlike pit vipers, coral snakes do not have heat-sensing pits and their pupils are round. Their venom is neurotoxic, affecting the nervous system, while pit viper venom is primarily hemotoxic, impacting blood and tissue.
Geographic Distribution Across the USA
Rattlesnakes are the most widespread venomous snakes in the United States, inhabiting diverse environments from deserts to forests. Specific species inhabit different regions; for instance, the Eastern Diamondback Rattlesnake, one of North America’s largest venomous snakes, is found across the southeastern coastal plain, from eastern North Carolina to Florida and west to Louisiana. The Western Diamondback Rattlesnake, another large species, primarily occupies the southwestern United States, including Texas, Oklahoma, Arizona, and parts of California. Timber Rattlesnakes are found throughout much of the eastern and central United States, preferring wooded areas.
Copperheads are common throughout the eastern and central United States, ranging from Massachusetts south to northern Florida and west to Nebraska and Texas. They are often encountered in suburban and rural areas, favoring woodlands, rocky outcrops, and riparian habitats. Their camouflage allows them to blend seamlessly with leaf litter, making them particularly difficult to spot. These snakes are responsible for a significant number of snake bites due to their prevalence and tendency to freeze rather than flee when approached.
Cottonmouths, also known as water moccasins, are semi-aquatic pit vipers found primarily in the southeastern United States. Their range extends from southeastern Virginia, through Florida, and west to eastern Texas, inhabiting swamps, marshes, ponds, lakes, and slow-moving streams. They are strong swimmers and are often seen near water sources. Their unique defensive posture, where they open their mouth to display a white interior, gives them their common name.
Coral snakes have a more restricted distribution, primarily found in the southern United States. The Eastern Coral Snake is native to the southeastern coastal plain, from North Carolina to Florida and west into Louisiana. The Texas Coral Snake is found in Texas, Louisiana, and Arkansas, while the Arizona Coral Snake inhabits parts of Arizona and New Mexico. These secretive snakes spend much time underground or under debris, making encounters less common than with pit vipers.
Identifying Venomous Snakes
Identifying venomous snakes can be challenging, but certain features offer clues. Pit vipers, such as rattlesnakes, copperheads, and cottonmouths, typically have a triangular-shaped head distinctly wider than their neck. Their pupils are vertical slits. A small loreal pit is located between their eye and nostril on each side of the head. Rattlesnakes are uniquely identified by the presence of rattles at the end of their tail, which they shake to produce a warning sound.
Coral snakes have a different appearance, characterized by bright, alternating bands of red, yellow, and black. A common rhyme, “red on yellow, kill a fellow; red on black, friend of Jack,” helps distinguish venomous coral snakes from non-venomous mimics. For venomous coral snakes, the red bands touch the yellow bands. It is important to remember that these are general guidelines, and definitive identification should only be made by experts.
Encountering a Snake and Bite Management
If you encounter a snake, the safest approach is to give it ample space and avoid any attempts to interact with it. Snakes typically do not want to engage and will move away if given the opportunity. Slowly back away from the snake, maintaining a safe distance, and never try to capture, handle, or provoke it. Most snake bites occur when people try to kill or interact with the snake.
Should a snake bite occur, remaining calm is the first and most important step to manage the situation. Immediately seek medical attention by calling emergency services or going to the nearest hospital. While waiting for medical help, remove any jewelry or tight clothing from the bitten limb, as swelling can occur rapidly. Keep the bitten area at or below heart level to help slow the spread of venom.
Cleaning the wound gently with soap and water can help prevent infection. It is crucial to avoid actions that can worsen the situation, such as applying a tourniquet, cutting the wound, attempting to suck out the venom, or applying ice. These measures are ineffective and can cause further harm to the bitten individual. Prompt medical care, which may include antivenom, is the only effective treatment for venomous snake bites.
References
Venomous Snakes. National Park Service. https://www.nps.gov/articles/venomous-snakes.htm
Coral Snakes. Florida Museum of Natural History. https://www.floridamuseum.ufl.edu/herpetology/fl-snakes/venomous-snakes/coral-snakes/