According to scientists, rattlesnakes have evolved clever ways to convince humans that danger is closer than they think.
The sound of the tail swaying becomes louder as the person approaches, but suddenly switches to a much higher frequency.
In the test, participants believed that the snake was much closer than it really was due to the sudden changes in sound.
Researchers say the traits have evolved to help prevent snakes from being trampled.
The rattlesnake’s tail sibilant has long been a movie staple.
The hard keratin ring at the tip of the reptile’s tail sways rapidly, causing the story to rattle.
Keratin is the same protein that makes up our nails and hair.
The key to noise is the ability of a snake to shake its tail muscles up to 90 times per second.
This violent shaking is used to warn other animals and humans of their existence.
Nevertheless, rattlesnakes are still responsible for most of the 8,000 or so bites given to Americans each year.
Researchers have known for decades that the frequency of rattling sounds can change, but little research has been done on the importance of sound changes.
In this study, scientists conducted experiments by bringing a human-like torso closer to a Western diamondback rattlesnake and recording its reaction.
As the object approached the snake, the rattle frequency increased to about 40Hz. This was followed by a sudden jump of sound into the higher frequency range of 60-100Hz.
To understand what a sudden change means, researchers conducted further research with human participants and virtual snakes.
The rate of increase in rattling was perceived as increasing loudness as participants approached.
Scientists have discovered that when a sudden change in frequency occurred at a distance of 4 meters, people in the test believed it was much closer, about 1 meter away.
The authors believe that sound switching is not just a warning, but a complex interspecies communication signal.
“The sudden switch to high frequency mode acts as a smart signal that tricks the listener into the actual distance to the source,” said Boris Chagnaud, senior author at Karl-Franzens-University in Graz, Austria.
“The misunderstanding of distance by listeners creates a safety margin for distance.”
The author believes that snake behavior utilizes the human auditory system. The human auditory system has evolved to interpret increased loudness as moving faster and approaching.
“Evolution is a random process, and what we can interpret as an elegant design from today’s point of view is actually the result of thousands of trials of snakes encountering large mammals,” said Dr. Chagnaud.
“The rattling noise of the snake co-evolved with the hearing of mammals through trial and error, leaving behind the snake that was most able to avoid being trampled.”
NS The study has been published It is in the journal Current Biology.
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