Snakes Might Say ‘Better to Hear You With’
Watch what you say around a snake, or at least how loud you say it. A paper published in PLOS ONE, indicates snakes use hearing to help them interpret the world, and finally dispel the myth that snakes are deaf to airborne sound.
The research included 19 different snakes representing seven species. The study reveals that not only do snakes have airborne hearing, just like we do, but that different species react differently to what they hear.
The study doesn’t contradict what you might have learned in biology class or watching nature specials on TV, snakes do primarily sense their world using what’s called the Jacobson’s organ, as they flick their tongues out to check out ‘what’s what.’
Still, it makes sense that since snakes are susceptible to predators like monitor lizards, other snakes, some birds of prey and people to name just a few hearing is an important sense for both predator avoidance and injury avoidance (such as being stepped on).
Using silence as a control, researchers played one of three sounds, each including a range of frequencies: 1–150Hz, 150–300Hz and 300–450Hz. For comparison, the human voice range is about 100–250Hz, and birds chirp at about 8,000Hz.
As one example of a result, Woma pythons (Aspidites ramsayi) – a non-venomous snake found throughout Australia’s arid interior – significantly increased their movement in response to sound and actually approached it. They exhibited an interesting behavior called “periscoping,” in which snakes raise the front third of their body in a manner that suggests curiosity. Interesting in itself is that snakes might express curiosity.
In contrast, three other genera – Acanthophis (death adders), Oxyuranus (taipans) and Pseudonaja (brown snakes) – were more likely to move away from the sounds, signaling potential avoidance behavior.
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. So, it makes sense they trended away from the sound. For them, survival means avoiding being trampled by large vertebrates such as kangaroos, wombats or humans.
This study further discredits the myth that snakes are deaf. They can hear, though not nearly as well as humans, as hearing isn’t their primary sense organ.
So, can snakes hear us? Well, that depends not on what you say but how loud you say it. The frequency of the human voice is about 100–250Hz, depending, in great part, on sex. Many snakes did respond to around 85 decibels, the sound of a loud person. Now, the question which remains unanswered: Do snakes care what we say?
An interesting Australian Eastern Brown Snake Video: