While snakes lack external ears and a middle tympanic ear, they are not deaf. But how snakes naturally respond to sound is still unclear.
A University of Queensland-led study has found that snakes can hear and react to airborne sound as well as ground vibrations.
Scientists conducted 304 controlled experiment trials on 19 snakes across five genera in a soundproof room. They observed the effects of three sounds on individual snake behavior compared to controls.
The study is the first of its kind that used non-anesthetized, freely moving snakes. It found that the snakes react to soundwaves traveling through the air and possibly human voices.
Dr. Christina Zdenek from UQ’s School of Biological Sciences said, “We played one sound which produced ground vibrations, while the other two were airborne only. It meant we were able to test both types of ‘hearing’ – tactile hearing through the snakes’ belly scales and airborne through their internal ear.'”
“The reactions strongly depended on the genus of the snakes.”
“Only the woma python tended to move toward the sound, while taipans, brown snakes, and especially death adders were all more likely to move away from it.”
“The behavioral reactions also differed, with taipans, in particular, more likely to exhibit defensive and cautious responses to sound.”
“The different reactions are likely because of evolutionary pressures over millions of years, designed to aid survival and reproduction. For example, woma pythons are large nocturnal snakes with fewer predators than smaller species and probably don’t need to be as cautious, so they tended to approach sound.”
“But taipans may have to worry about raptor predators, and they also actively pursue their prey, so their senses seem to be much more sensitive.”
“The findings challenge the assumption that snakes can’t hear sound, such as humans talking or yelling, and could reshape the view on how they react to sound.”
“We know very little about how most snake species navigate situations and landscapes around the world. But our study shows that sound may be an important part of their sensory repertoire.”
“Snakes are very vulnerable, timid creatures that hide most of the time, and we still have so much to learn about them.”
Journal Reference:
- Christina N. Zdenek et al. Sound garden: How snakes respond to airborne and groundborne sounds. PLOS ONE. DOI: 10.1371/journal.pone.0281285