Recent research has shown that rattlesnakes abruptly change their clicking frequency to trick the human ear, and possibly that of other animals.
An intelligent signal
Similar to accelerating beeps as a reversing vehicle nears an obstacle, the rattlesnake warning click starts at a slow rate, gradually increasing before suddenly changing to a constant sound at high frequency. ” This gives the impression that danger is imminent, as these reptiles can be found a meter away. “, Explain Boris Chagnaud, researcher atUniversity of Graz in Austria and lead author of the new study published in the journal Current Biology.
Read alsoThese strange prehistoric creatures appeared in the footsteps of dinosaurs
« Such an auditory illusion is akin to a smart signal, probably preventing the snake from being stepped on or wasting its precious venom. », Continues the researcher. ” It makes it clear to you that you are too close. »
When studying rattlesnake terrariums a few years ago, Chagnaud had been surprised to find that the snakes’ clicking speed changed as they approached or retreated. Collaborating with scientists fromTechnical University of Munich, the researcher carried out experiments involving 30 of their crotales du Texas (Crotalus atrox), which reacted to the approach of a dummy human torso placed on rails, as well as a growing black circle formed by light projections on a screen.
—
video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
Crotalux atrox in a defensive position
In both tests, the rate gradually increased to about 40 clicks per second, then suddenly changed to a constant high-frequency sound, ranging from 60 to 100 clicks per second depending on the reptile.
Read alsoCuttlefish’s incredible brain holds memories that never seem to fade
Very effective hearing illusions
The team then conducted virtual reality experiments in which 11 subjects were asked to move around a virtual grass field, and press a button when they thought they were in close proximity to the sound source. It turned out that they were easily fooled by the sudden change in the speed of the clicking noise.
« They thought they were one meter from the virtual snake, when in reality they were more like four meters “, Explain Chagnaud.
The results of the study suggest that snakes developed a remarkable ability to distort our perception of distance by separating us, using sounds. ” They don’t try to warn us to keep us from getting bitten », Underlines the researcher. ” Above all, they announce their presence to protect themselves. »
Read alsoImprisonment, torture, fire … The falcon will stop at nothing to capture its prey
