Shaking the tail when threatened is a common snake defense, not something only rattlesnakes do.1Wikipedia. Tail vibration A buzzing sound from leaves or grass can come from several kinds of snake, some harmless and some not. The habit is very old and shared across snake families, and the rattlesnake’s rattle is a later, fancier version of it.2PubMed. Behavioral Plasticity and the Origins of Novelty: The Evolution of the Rattlesnake Rattle
Snakes That Shake Their Tails Without a Rattle
Tail vibration is especially widespread among New World vipers and colubrids, the large family that contains most harmless snakes.3Wikipedia. Tail vibration In North America, the tail-shakers include gopher snakes and bullsnakes, rat snakes, fox snakes, racers, whipsnakes, kingsnakes, and milk snakes. None of them has a rattle, the stack of hollow, interlocking keratin segments at a rattlesnake’s tail tip.
Where you are matters for which one you meet. Gopher snakes and bullsnakes are common across the arid and grassland West. Rat snakes and black racers turn up in eastern yards and barns, and fox snakes live around the Great Lakes and Midwest.
Some tail-shakers are venomous too. Copperheads shake, or “rattle,” their tails as a person gets closer.4Home & Garden Information Center. Identifying Copperhead Snakes The cottonmouth, a close relative of the copperhead, also vibrates its tail. Copperheads have hourglass-shaped bands and live in woods, leaf litter, and around woodpiles, and they are common across much of the East and South. Cottonmouths live near water in the Southeast, so a buzzing tail near a pond or ditch there deserves extra caution.
A snake without a rattle can still sound like one because the tail itself makes almost no noise in the air. The buzz comes from the tail tip hitting dry leaves, grass, or debris. On bare ground or pavement, the same snake can be nearly silent. In dead leaves it can produce a dry buzz that is easy to mistake for a rattle when you only hear it.
That is why the rattle is the one reliable difference. Its loose, hollow segments click against each other, so it makes sound by itself, in open air. Looking for it is the clearest test, but it means seeing the tail tip, which is not always safe or possible.
The Gopher Snake, the Best Rattlesnake Impostor
Gopher snakes are common in dry parts of the western US.5Wildlife Conservation Society. WCS Wild View: A Daunting Defense When cornered, they flatten the head, buzz the tail against vegetation, and rear into a striking pose.6Wildlife Conservation Society. WCS Wild View: A Daunting Defense The buzz against debris can sound like a real rattle, and only people who know the species tend to see the difference.7Wildlife Conservation Society. WCS Wild View: A Daunting Defense Yet gopher snakes, including bullsnakes, are nonvenomous constrictors.8Wildlife Conservation Society. WCS Wild View: A Daunting Defense
They also hiss. A gopher snake forces air past a flap of tissue in its windpipe, producing a loud, harsh hiss that carries well. Together with the tail buzz, a flattened head, and a puffed-up body, it is very convincing at close range. The hiss is part of the bluff and says nothing about venom.
The body gives it away, though you shouldn’t get close to check. A gopher snake’s tail is narrow and tapers to a point, while a rattlesnake’s ends in rattle segments or, in a young snake, a small button. Even with its head flattened, a gopher snake’s head is usually narrower and less blocky. Gopher snakes have round pupils and rattlesnakes have slit-shaped ones, but you would need to be uncomfortably close to see them. Blotched tan and brown markings are shared by both snakes, so color alone is a poor guide.
How to Tell a Real Rattlesnake From a Look-Alike
Rattlesnakes can shake their tails up to about 90 times per second.9Wikipedia. Tail vibration – Wikipedia The fastest look-alikes, copperhead relatives and New World colubrids, top out around 50 times per second.10Wikipedia. Tail vibration – Wikipedia Only 2 of 33 rattlesnakes filmed were slower than the fastest look-alikes.11Wikipedia. Tail vibration So a rattlesnake tends to make a higher, smoother buzz, while a look-alike sounds more like a rougher patter.
Rattlesnakes can also keep it up for a long time. The western diamondback can rattle continuously for hours,12The Company of Biologists (J Exp Biol). Structural correlates of speed and endurance in skeletal muscle: the rattlesnake tailshaker muscle because its tail-shaking muscle is packed with energy-producing structures that let it contract very fast without tiring.13The Company of Biologists (J Exp Biol). Structural correlates of speed and endurance in skeletal muscle: the rattlesnake tailshaker muscle Use the sound as a clue, not a verdict: distance, wind, and the surrounding leaves change how a buzz sounds, so a single listen is easy to misjudge.
If you can see the snake from a safe distance, check in this order. Start with the tail tip, looking for a jointed button or stack of segments, the clearest sign of a rattlesnake. Next, notice whether the sound carries on when the tail is in open air rather than touching leaves, because only a rattle works that way. Then look at the overall shape: rattlesnakes are heavy-bodied, with a wide, triangular head and a thinner neck. If you can’t tell from where you stand, treat the snake as venomous and keep your distance.
Several common mistakes get people in trouble. A triangular head isn’t proof, since harmless snakes flatten theirs when threatened. Baby rattlesnakes have only a single button and make little sound. A rattlesnake can lose its rattle segments and still be venomous, and rattlesnakes don’t always rattle before striking.
Why Harmless Snakes Copy the Rattle
Harmless species often copy a dangerous species’ warning, but few known cases involve sound.14Ethology Ecology & Evolution. Microevolutionary change in mimicry? Potential erosion of rattling behaviour among nonvenomous snakes on islands lacking rattlesnakes The buzz of a harmless snake may be one of them, copying the rattlesnake’s warning.15Ethology Ecology & Evolution. Microevolutionary change in mimicry? Potential erosion of rattling behaviour among nonvenomous snakes on islands lacking rattlesnakes Some American snakes vibrate so much like nearby rattlesnakes that they appear to be imitating them.16Science News. Tail vibrations may have preceded evolution of rattlesnake rattle
A predator that has learned to fear a rattlesnake’s sound may back off when it hears something similar, even from a snake that cannot hurt it. The harmless snake gets the benefit of the warning without paying for venom. The predator doesn’t need to see the snake clearly, only to hear the buzz. Gopher snakes living alongside rattlesnakes shake their tails longer than those on islands without rattlesnakes,17Wikipedia. Tail vibration – Wikipedia which suggests the display is tuned to local predators that know the real thing and fades where there is nothing to copy.
The habit also came before the rattle. Tail vibration is nearly universal among vipers and common in harmless snakes, which suggests a shared, ancient origin.18PubMed. Behavioral Plasticity and the Origins of Novelty: The Evolution of the Rattlesnake Rattle The closer a species is related to rattlesnakes, the more its shaking resembles theirs in speed and length.19PubMed. Behavioral Plasticity and the Origins of Novelty: The Evolution of the Rattlesnake Rattle So the rattle likely evolved by adding a noisemaker to an old habit.20PubMed. Behavioral Plasticity and the Origins of Novelty: The Evolution of the Rattlesnake Rattle
What to Do When a Snake Shakes Its Tail at You
Tail vibration is a defensive response to a perceived predator.21Wikipedia. Tail vibration The snake is warning you off, and stepping back usually ends it. Since copperheads shake too, don’t assume a rattleless snake is safe.22Home & Garden Information Center. Identifying Copperhead Snakes
On a trail or in the yard, stop moving as soon as you hear the sound and locate where it is coming from before you step anywhere. Once you spot the snake, back away slowly, putting at least a body length or two between you and it. Keep dogs leashed and away from the snake, since curious pets are often bitten when they investigate. Don’t try to pick up, kill, or move the snake yourself, because that is when many bites happen.
If the snake is near the house, watch where it goes from a safe distance so you can tell someone where it is. Call local animal control or a wildlife removal service rather than handling it yourself. Clearing woodpiles and debris reduces hiding places for rodents and the snakes that follow them.
If someone is bitten, call emergency services right away for any bite from an unidentified snake. Keep the person still, with the limb at a comfortable, relaxed level, and remove rings and tight items before swelling starts. Don’t cut the wound, suck out venom, or apply ice or a tourniquet.
Snakes That Benefit You When Left Alone
Gopher snakes and rat snakes eat mice, rats, and gophers, so leaving them alone can reduce rodent damage around yards and barns. They rarely bite unless cornered or handled, and their bites are not venomous.
Killing them tends to backfire, since it removes a predator that eats mice and rats. Many states protect certain snake species, so killing one may also be against the law.
Living alongside snakes takes a few habits. Wear boots and carry a flashlight at night, when you are more likely to step near a snake without seeing it. Seal gaps under doors and around foundations to keep both rodents and snakes out of the house. Teach children to back away from any snake and tell an adult, instead of approaching or touching it.