It’s been commonly believed for years that snakes are deaf, and if you say, “Oh my god, look out for that snake” in a normal voice, it’s probably true that the serpent in question won’t hear you. But who says that in a normal voice? If you scream it, or even say it loudly, according to a new study from Australian researchers, that snake most likely hears you—and the finding could even help people avoid snakebites.
“Experts have long understood that snakes can feel sound vibrations through the ground – what we call ‘tactile’ sensing,” wrote the study’s lead author, Dr. Christina N. Zdenek, in article published in The Conversation. “But we’ve puzzled over whether they can also hear airborne sound vibrations, and particularly over how they react to sounds.”
Zdenek and her colleagues approached this conundrum by bringing 19 different snakes, representing seven different species, into a sound-proof room at the Queensland University of Technology’s School of Creative Practice. While playing one of three sounds in a range of frequencies that stretched from 1-150 hertz up to 300-450 hertz, researchers observed the behavior of each individual snake The human voice falls somewhere in the middle—between 100 and 250 hertz.
Reactions to Sounds Were Dependent on Species
Researchers found that the snakes responded to airborne sounds, but in different ways depending on their species. Woma pythons, for example, moved in to investigate the noises. “They exhibited an interesting behavior called ‘periscoping,'” wrote Zdenek. A motion, she said, “in which snakes raise the front third of their body in a manner that suggests curiosity.” Picture a king cobra poised in its infamous upright position, and you’ll have a pretty good mental image of a what a periscoping python might look like.
Other snake species weren’t quite as brazen in the face of artificially produced lab noises. Death adders, taipans, and brown snakes tended to shy away from the sounds. In the case of death adders, this type of “avoidance behavior” makes good evolutionary sense, Zdenek said.
“Death adders are ambush predators. They wait for their prey to come to them using the lure on their tail (which they wiggle to look like a worm), and they can’t travel quickly,” she wrote. “So it makes sense they trended away from the sound. For them, survival means avoiding being trodden on by large vertebrates such as kangaroos, wombats or humans.”
Taipans and brown snakes are venomous foragers that spend daylight hours in near constant search of food. Because of their propensity to move about in the daytime, they’re frequently preyed upon by large raptors. According to the researchers, these three species were acutely aware of the audible stimuli produced during the trials, and they responded with both cautious and defensive behaviors.
Can Loud Noises Deter Snakes?
The big takeaway from the Australian study seems to be that snakes definitely aren’t deaf, a claim that many people have made in the past. While they can detect your approach through subtle ground vibrations, they can also hear you coming via airborne sound waves—if you’re being loud. But how loud is loud enough?
“We played the aforementioned sounds from three speakers at a time from one side of the room or the other, randomly,” the authors wrote in their introduction to the study. “[Each speaker] was calibrated to an intensity of 85 decibels.” That’s fairly loud, according to most hearing experts. For comparison, normal conversation comes in at around 65 dB.
But don’t abandon your snake boots in favor of a loud speaker just yet. Whether a snake opts to slither away from your raucous approach, hold tight in an ambush-type posture, or move in for a closer look seem totally dependent on the type of snake you happen to encounter. Regardless, the scientists behind the study think their findings could ultimately keep people safe while traveling around in snake country. “Our results improve our limited understanding of snake behavior,” they concluded. “[This] may help humans deter snakes and/or avoid snakebites.”