High-speed cameras have finally debunked a long-held myth: That venomous vipers such as rattlesnakes have much faster strikes than nonvenomous snakes.
In some cases, harmless snakes actually have speedier strikes.
“If you put me up against a wall, shined a bright light in my eyes, and asked me if large-bodied vipers had faster strikes, I’d say, ‘Yeah, they probably do,’” says Rick Shine of Australia’s University of Sydney, who wasn’t involved with the research. “I was the victim of a very common misconception.”
The study, published recently in Biology Letters, marks the latest effort to debunk the persistent legend surrounding vipers’ speed, which lit up the Wild West with absurd tales of rattlesnakes striking at bullets fired in their general direction.
“It’s outlandish, but it’s kind of pervasive,” says study leader David Penning, a Ph.D. student at the University of Louisiana at Lafayette.
Penning normally studies nonvenomous snakes, such as the Texas rat snake (Pantherophis obsoletus), but he became interested in how the snakes—which grow up to six feet (1.8 meters) long—strike their prey when they’re different sizes. (See National Geographic's pictures of snakes.)
When undergraduate researcher Baxter Sawvel began filming adult rat snakes’ strikes, he noticed that they were just as fast as many vipers—too fast, in fact, for Penning to believe the original results.
“I talked with my adviser, and we both had this built-in assumption that the vipers should be the fast ones,” says Penning. “That’s what the literature says. That’s what basically any documentary that talks about snake striking says.”
To Penning’s surprise, the more he pored over previously published studies, the more he realized that scientists hadn’t really put the vipers’ speed-record claims to the test.
So the team designed a chamber that allowed them to safely film rat snakes striking at a stuffed glove, as well as strikes from two venomous vipers: the cottonmouth (Agkistrodon piscivorus), and the western diamondback rattlesnake (Crotalus atrox).
The footage clearly showed that the rat snakes were just as quick as their venomous counterparts, with similar strike speeds, accelerations, and strike durations.
That’s not a surprise, says Penning, since venomous and nonvenomous snakes capture similarly quick prey, such as rabbits and mice. (“Watch an Eagle Battle a Cobra in Dramatic New Video.”)
In fact, the second fastest individual strike the team measured belonged to a rat snake, which launched its head with an acceleration of 274 meters per second squared, equivalent to 28 times the downward pull of gravity.
That’s incredibly fast. If a car sped up that quickly, it would go zero to 60 miles (97 kilometers) an hour in less than a tenth of a second, subjecting anyone inside to unimaginably intense G-forces.
And unlike animals such as chameleons, which can launch their tongues with similarly mind-bending speed, the snakes are flinging decidedly more precious cargo.
“Snakes are launching their heads, which are incredibly sensitive parts of their bodies, with accelerations that the most trained pilots on the planet can’t withstand for very long, if at all,” says Penning. “It’s astonishing.”
But how exactly snakes’ bodies generate such powerful strikes remains a mystery.
The scientists’ next step is to decipher snakes’ elaborate musculature, which contains up to 15,000 muscles—20 times as many as are in the human body.
“There’s so many muscles pulling on different parts, we don’t have a great idea of what is moving what,” Penning says.
“It’s amazing how much we have left to learn.”
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