Recent research has shown that rattlesnakes abruptly change the frequency of their pecking to trick the human ear, and possibly the ear of other animals.
smart signal
Similar to accelerating beeps as a reversing vehicle approaches an obstacle, the rattlesnake warning click begins at a slow rate, gradually increasing before suddenly turning into a steady sound at a high frequency. ” This gives the impression that danger is imminent, since these reptiles can be found within a meter. ‘, he explains Boris Chagnot, researcher inUniversity of Graz in Austria and lead author of the new study published in the journal current biology.
« Such an auditory illusion is like a clever signal, perhaps preventing a snake from stepping on it or losing its precious venom. The researcher continues. ” Shows you’re very close. »
When studying rattlesnakes a few years ago, Shagno I was surprised to find that the snakes’ pecking speed changed as they approached and retreated. Collaboration with scholars fromTechnical University of MunichThe researcher conducted experiments that included 30 of them Crotales de Texas (Crotalus Atrox), which interacted with the approach of a false human torso placed on rods, as well as a growing black circle formed by light projections on the screen.
In both tests, the rate gradually accelerated to about 40 clicks per second, then changed abruptly to a steady, high-frequency sound, ranging from 60 to 100 clicks per second depending on the reptile.
Very effective in hearing illusions
The team then conducted virtual reality experiments where 11 people were asked to walk around a virtual grass field, press a button when they thought they were close to the source of the sound, and were surprisingly easily fooled. Change in click noise speed.
« They thought they were one meter away from the hypothetical snake, when in fact they were closer to four meters ‘, he explains Shagno.
The results of the study suggest that snakes have developed a remarkable ability to distort our perception of distance by separating us using sounds. ” They are not trying to warn us to prevent us from getting bitten ‘,” the researcher points out. ” Above all, they declare their existence to protect themselves. »
