Identifying venomous snakes is crucial for public safety, especially for those outdoors. Understanding the distinctions between venomous and non-venomous species helps prevent dangerous encounters. While encountering a snake can be startling, maintaining a calm and cautious demeanor is important. Recognizing key physical and behavioral traits aids in making informed, safe decisions.
Dispelling Common Identification Myths
Many widely circulated beliefs about identifying venomous snakes are inaccurate and can lead to misidentification. A common misconception is that all venomous snakes have a triangular head. While many venomous pit vipers possess a broad, triangular head, numerous non-venomous snakes can flatten their heads defensively. This mimicry makes head shape alone an unreliable identification method.
Another frequent myth suggests all venomous snakes have slit, cat-like pupils, while non-venomous snakes have round pupils. While many pit vipers exhibit vertical pupils, the venomous coral snake has round pupils. Discerning pupil shape from a safe distance is often impractical and risky. Relying on a single characteristic is misleading, as these features are not universally present across all venomous species.
Reliable Physical Clues for Venomous Snakes
Certain physical characteristics provide more reliable clues for identifying venomous snakes, particularly pit vipers. Loreal pits are small, heat-sensing organs located on each side of the head, between the eye and the nostril. These distinct pits, larger than nostrils, enable pit vipers to detect warm-blooded prey. This specialized sensory organ is absent in non-venomous snakes.
Another indicator, though requiring closer observation, is the arrangement of subcaudal scales on the tail’s underside. Pit vipers generally have a single row of undivided scales extending from the anal plate to the tail tip. Most non-venomous snakes typically have a double row of divided subcaudal scales. While all venomous snakes possess fangs for venom delivery, these specialized teeth are often not visible from a safe distance. Observing fangs means being too close.
Identifying Major Venomous Snake Families
In North America, venomous snake families include pit vipers and elapids. Pit vipers, encompassing rattlesnakes, copperheads, and cottonmouths, share several common traits. They typically have stout bodies, triangular heads, vertical pupils, and heat-sensing loreal pits. Their scales are often keeled, meaning they have a raised ridge, giving them a rough texture.
Rattlesnakes, Copperheads, and Cottonmouths
Rattlesnakes are recognized by the segmented rattle at their tail’s end, which produces a distinct sound when vibrated. However, young rattlesnakes may only have a single “button” and not produce a clear rattle, or the rattle can break off. Copperheads are identifiable by their coppery-tan coloration and distinctive hourglass-shaped crossbands that are narrow along the spine and wider on the sides. Their head is often a coppery color, matching their name.
Cottonmouths, also known as water moccasins, are heavy-bodied snakes found near water. They typically have dark brown to black bodies with broad crossbands that may become obscure with age. They are named for the white interior of their mouth, which they display as a defensive warning. Non-venomous water snakes are often mistaken for cottonmouths, but water snakes usually have round pupils and their eyes are visible from above their head, unlike cottonmouths whose eyes are obscured when viewed from above.
Coral Snakes
Coral snakes, members of the elapid family, are slender with bright, distinctive banding patterns of red, yellow, and black. A common mnemonic to differentiate them from non-venomous look-alikes, like king snakes, is “Red and yellow, kill a fellow; red and black, friend of Jack.” This means that on a venomous coral snake, the red bands touch yellow bands. In contrast, on non-venomous king snakes, red bands touch black bands. Coral snakes typically have a black head with a short snout, while king snakes often have a red head and a longer snout.
Regional Distribution and Behavioral Indicators
Understanding the specific venomous snake species native to a geographic region significantly narrows identification possibilities. Local wildlife guides and resources provide detailed information about snakes in your area. A snake’s behavior can also provide clues, though these should not be the sole basis for identification.
When threatened, rattlesnakes often vibrate their tails, producing a characteristic rattling sound as a warning. However, a rattlesnake may not always rattle before striking, especially if startled. Cottonmouths, when threatened, may coil their bodies and open their mouths wide, revealing the pale, white lining inside, a behavior known as “gaping.” While these behaviors serve as warnings, snakes generally prefer to avoid confrontation and attempt to escape. Approaching or provoking a snake to observe its behavior is not recommended, as it can lead to a defensive strike.