While deaths caused by venomous, or poisonous, snakes are rare, it’s important to know these common characteristics of venomous snakes in the United States so that you can avoid them while hiking. Within the United States, the four major types of venomous snakes include rattlesnakes, copperheads, cottonmouths (water moccasins), and coral snakes.
Three out of four common types of venomous snakes in the United States are pit vipers, a type of viper with a sensory pit on its face, whereas coral snakes are not. The pit vipers can be identified by several common features of venomous snakes outlined below, but coral snakes are more easily identified by their distinctive color pattern. While exceptions do exist, knowing the characteristics below will help you identify and avoid a potentially dangerous snake.
Look first at the head of the snake you encounter, as the head shape is perhaps the most easily identifiable feature. Venomous snakes in the United States will have a triangular or arrow-shaped head, with the arrow point at the snake’s mouth or snout. The head has a flat rather than a round shape.
Venomous snakes in the United States have slit-like eye pupils rather than round pupils. The pupil of a venomous snake will resemble a cat’s vertical, elliptical pupil.
Since three out of the four types of venomous snakes in the United States are pit vipers, look for the presence of a pit on the snake’s face to determine if it falls into this category. The pit, or hole, will usually be between the snake’s nostrils and eyes or to the sides of its eyes on each side of the head. These heat-sensitive sensory pits essentially help venomous snakes locate warm-bodied prey.
Even though you hopefully won’t see or feel a venomous snake’s fangs, they’re retractable and hollow so that they can deliver venom into the victim’s body when they strike.
Most venomous snakes in the United States have varied rather than solid color patterns. Some of the color patterns may appear as bands, or stripes, or as diamond-shaped patterns.
Rattlesnakes are among the venomous snake population in the United States, and they can be identified easily by the presence of a keratin rattle at the end of their tail. Rattlesnakes will shake the rattle to produce a sound when threatened, so listen for this warning signal.
Also look at any shed snake skin that you may come across to determine the presence of venomous snakes in the area. Venomous snakes generally have a single row of scales on the underside of the tail, whereas non-venomous snakes commonly have a double row of scales.
Since coral snakes are not pit vipers, they lack most of the common pit viper characteristics. Coral snakes have a rounded rather than angular head. They also have round pupils in their eyes, and they won’t have pits. Look instead for this snake’s characteristic black, yellow, and red stripe pattern. Non-venomous snakes can also have these colors, but the venomous version will have the red and yellow stripes touching, so it will help you to remember this rhyme: “Red on yellow, kill a fellow.”