Scientists have recently discovered that geckos have a sixth sense that detects low-frequency vibrations. Until now, only water-based creatures like amphibians and fish have shown this ability. This duality — both hearing and vibration sensing — suggests how hearing evolved from fish to land animals. People might have this residual ability, too.
“The ear, as we know it, hears airborne sound. But this ancient inner pathway, which is typically linked to balance, helps geckos detect vibrations that travel through mediums like the ground or water,” said study co-author Catherine Carr.
The vibration detector, called the saccule, sits in the gecko’s inner ear. It is vital for balance and completely independent of the gecko’s normal hearing mechanism.
With just their normal ears, geckos can hear higher-frequency sounds between 1,600 and 5,000 Hertz. The saccule targets the lower end of the spectrum, allowing them to detect faint low-frequency vibrations between 50 and 200 Hertz.
The gecko: two ways of hearing. Photo: Shutterstock
The researchers think that this link between the geckos’ hearing and the part of the inner ear that affects balance might also be present in humans.
“Think about when you’re at a live rock concert. It’s so loud that you can feel your whole head and body vibrate in the sound field. You can feel the music, rather than just hear it…meaning our sense of hearing and balance may also be closely linked,” said Carr.
The discovery also hints that other reptiles might actually be able to hear.
“A lot of snakes and lizards were thought to be ‘mute’ or ‘deaf’ in the sense that they do not vocalize sounds or hear sounds well,” explained lead author Dawei Han. “But they could potentially be communicating via vibrational signals.”
