Scientists have found that rattlesnakes make an abrupt change in the frequency of rattlesnakes to trick predators like humans into thinking they are closer than they really are.
The new study, published in Current biology, suggests that Western diamond rattlesnakes may use their tanned booties as a deception tool.
“Our data show that the acoustic visualization of rattlesnakes, which has been interpreted for decades as a simple audible warning signal about the snake’s presence, is in fact a much more intricate interspecies communication signal,” he says. the co-author of the study, Boris Chagnaud, a biologist at the Austrian Karl-Franzens University in Graz, in a press release. Chagnaud compares the increase in rattle frequency to a reversing car that emits sound faster and faster as it approaches an object.
It’s no secret that rattlesnakes use rattles — hollow keratin structures made with the same things as human fingernails — to make their presence known, but it’s less understood how they use different rattle frequencies for defense. .
Chagnaud had the idea for the study after noticing that a snake at a visiting animal care center staggered faster as it approached the enclosure. Chagnaud wondered how snakes might be using their rattle frequency to send a message to those closest to them. The message? “She is OK. I’m sitting here. Don’t step on me because I’ll bite you, ”says Chagnaud al New York News’ Sabrina Imbler.
To investigate his question, the research team designed a series of experiments in which an object — including a human-like torso and a large black disk — would approach a western diamond rattlesnake. As the object approached, the snake jumped from a low frequency rattle of about 40 Hz to one of 70 Hz. ScienceRachel Fritts. The exact distance of the snake caused it to move to a faster rattle varied by individual.
The team was curious as to whether the higher-frequency rattle really sounded closer to humans and sent 11 people to a virtual reality meadow peppered with hidden snakes. At lower frequency rattles, participants could estimate the distance of the virtual snake with reasonable accuracy. Then, when they reached less than four meters from the snakes, the rattle frequency jumped. When participants were asked to press a button when they believed they were within a meter of a virtual snake, they constantly underestimated the distance.
“Evolution is a random process, and what we might interpret from the current perspective as elegant design is in fact the result of thousands of tests of snakes found on large mammals,” Chagnaud says in a press release. auditory perception by trial and error, leaving those snakes that could best avoid being trampled. “
Higher frequency rattles may seem closer to humans due to a peculiarity in sound perception that causes individual rattle sounds to fuse into a single note. This note seems stronger despite being of the same amplitude, Jason Bittel reports National Geographic.
“Like other snakes, rattlesnakes, of which there are numerous species in North America, are more interested in not being detected than facing any other animal other than their prey,” says Whit Gibbons, a herpetologist. who did not participate in the study, on CNN. Megan Marples.
Misleading rattle tactics can help them avoid close encounters, which should be good news for humans.
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