Researchers at the University of Maryland have made a fascinating discovery about the auditory capabilities of geckos. They have found that geckos possess a unique ‘sixth sense’ that allows them to detect low-frequency vibrations through a part of their inner ear traditionally associated with balance and body positioning. This groundbreaking research challenges our understanding of animal sensory systems and may have implications for human hearing as well. Geckos are known for their remarkable abilities, and this new finding adds another fascinating layer to their sensory repertoire.
A Gecko’s Hidden Saccule
Published in the journal Current Biology, a new study finds that geckos use an inner-ear structure known as the saccule to sense low-frequency vibrations (50–200 Hz). Well below the spectrum geckos can hear via their ordinary auditory mechanism
The researchers said that it has been found in lizards for the first time but has been previously known to exist in fish and amphibians. The part of the ear that ‘we put something in’, is built to hear airborne sound. This ancient inner pathway is associated with balance, though it enables geckos to sense vibrations that pass through solid mediums such as the ground or water,” said study co-author Catherine Carr, a Distinguished University Professor of Biology at the University of Maryland.
Reimagining Animal Talk
This discovery has huge implications for what we know about how geckos can communicate and the way that scientists view the hearing abilities of reptiles. ”A common impression has been that many snakes and lizards are either ‘mute’ or ‘deaf,’ in the sense that they not vocalize sounds or hear sounds well,” said lead author Dawei Han, a postdoctoral researcher and former graduate student at the University of Maryland. ”But it seems like they could in fact be communicating through vibrational signals using this sensory pathway instead, which really alters the way scientists have thought about animal perception on a whole scale.
The researchers suggest that as yet unidentified sensory pathways used to detect this signal could also be present in other reptiles, potentially opening up whole new avenues for research into the communication and behavior of animals.
Evolutionary Consequences andHuman Hearing
The shared sensory pathway in modern reptiles, then, is informative about the evolutionary history of vertebrate sensory systems. Hearing mechanisms probably changed in a more detailed and gradual way than early reconstructions of the transition from water to land had assumed, the researchers pose.
These results have no direct bearing to human hearing, but he points out that there could be some interesting connections. Carr pointed out, “Think of when you’re at a live rock concert. It is so loud that your skull feels it vibrating in place within the sound field, and even your body. Instead of just listening to music, you get to feel it. The question may be whether we are stimulating the human vestibular system at those loud concerts, which indicates that our hearing and balance sense is also interconnected. By identifying and unraveling the biochemistry of these rare mutations in people, the scientists hope to motivate more study of mammalian hearing — actually one both hearing and equilibrium problems.
