Scientists at the University of Maryland have found that geckos have an unusual way of sensing vibrations that is changing what we know about how animals hear.
In a study published on October 4, 2024, in Current Biology, the researchers revealed that geckos use a part of their inner ear, called the saccule, to detect low-frequency vibrations.
This part of the ear was previously thought to only help with balance, but now it’s clear it plays a role in hearing too.
The study, led by biologists Catherine Carr and Dawei Han, shows that this “sixth sense” helps geckos detect vibrations in their surroundings, like those moving through the ground or water.
This adds a new layer to their regular sense of hearing and gives them more ways to understand what’s happening around them.
The researchers believe that this hidden hearing system might be present in other reptiles too, and it could change how we think about the evolution of hearing in animals.
Carr explained that the ear is usually thought of as a tool for hearing airborne sounds.
However, this ancient part of the inner ear helps geckos feel vibrations traveling through solid surfaces.
This type of hearing is common in amphibians and fish, but now scientists know it exists in reptiles like lizards too.
The geckos’ saccule can pick up vibrations in a range between 50 and 200 Hz, which is lower than what their normal hearing can detect.
Many reptiles, like snakes and some lizards, were previously thought to be “deaf” because they don’t hear airborne sounds well. But this discovery suggests that they might communicate using vibrational signals instead.
The researchers think this finding will lead to new studies about how reptiles, and possibly other animals, sense and communicate through vibrations.
Although this discovery doesn’t directly affect how humans hear, it opens up new questions about the connection between hearing and balance in mammals. For example, at loud concerts, people can often feel the music vibrating through their bodies.
This could mean that our own vestibular system (which controls balance) is involved in our sense of hearing as well.
The researchers hope their findings will inspire further studies into how mammals, including humans, use these hidden pathways for hearing and balance.
