Four types of venomous snakes exist in the United States: rattlesnakes, copperheads, cottonmouths (also known as water moccasins) and coral snakes. Each year, more than 7,000 Americans are bitten by one of these snakes. Many bites are a result of individuals attempting to handle or kill the snake, therefore this is not recommended. If you are bitten by a snake, seek medical assistance immediately. It’s also important to understand methods for distinguishing potentially venomous from non-venomous snakes in order to assess your potential risk. If you encounter a snake, leave the area and consider calling a wildlife professional who can help you identify the type of snake you have encountered. In the meantime, here are some tips that may help you to determine whether or not a snake is venomous or non-venomous.
While general identification tips are discussed here, we recommend consulting a trained wildlife professional in order to definitively distinguish venomous and non-venomous snakes.
Behavior and Habitat of Snakes
Behavior is one component that may help identify snakes. Each species of snake exhibits different behaviors. Thus, remembering these differences can pose a challenge to an untrained individual. Regardless, behavior observation is an important component that helps wildlife professionals determine the right solutions in situations when wildlife and humans interact. One of the most well-known behavior traits can be observed in the rattlesnake. When threatened, rattlesnakes may shake the rattles on their tails to create a loud clicking sound as a warning to potential predators. Be aware that not all rattlesnakes have rattles and this is not a reliable warning.
Observing nesting behaviors and knowledge of habitats can also be helpful when identifying potentially venomous or non-venomous snakes. For example, cottonmouths live in or near water. Thus, if there is a pond and/or swamp nearby, cottonmouths could be observed in the area, depending on geographic location. Similarly, in some geographic areas, copperheads live in wetland areas near forests and rivers.
While there are only four types of venomous snakes in the U.S., each type contains many subspecies with size and color variations that helps them blend in with their environments. Thus, coloring may not be an efficient method for distinguishing between a venomous and non-venomous snake. For example, venomous coral snakes and non-venomous scarlet king snakes both have a banded pattern of yellow, brown and black on their scales. The difference between the two types is that the red bands touch the yellow bands on a coral snake whereas red bands touch the black bands on scarlet king snakes.
Venomous snakes have distinct heads. While non-venomous snakes have a rounded head, venomous snakes have a more triangular-shaped head. The shape of a venomous snake's head may deter predators. However, some non-venomous snakes can mimic the triangular shape of non-venomous snakes by flattening their heads. This can help them appear more dangerous to potential predators.
Rattlesnakes, copperheads, cottonmouths and coral snakes are all considered pit vipers. These are venomous snakes distinguished by the pits (or holes) on their heads. Each snake has two pits that appear on their snouts. These pits allow snakes to detect infrared radiation from prey. Since it may be difficult to determine whether or not a snake has pits from a safe distance, consider contacting a wildlife professional to identify and potentially remove the snake for you. Even if the snake is dead or the head has been removed, avoid handling the head and use caution when inspecting, as you may still be at risk.
Examining a snake’s pupils is another method that can be utilized to identify venomous versus non-venomous snakes. Like a cat’s eye, venomous snakes have thin, black, vertical pupils surrounded by a yellow-green eyeball while non-venomous snakes have rounded pupils. While this type of pupils can indicate that the snake is venomous, this is observed at close range, which can be a potentially dangerous identification method.