To detect low-frequency vibrations, geckos use the saccule, a part of the inner ear traditionally associated with maintaining balance and body position, the institute’s biologist duo said. University of Marylandthis special “sixth sense” serves as a complement to the gecko’s normal sense of hearing and how it senses the world around it.

“As we know, the ear hears sounds in the air,” says Katherine Kerr, a professor at the University of Maryland.

“However, this ancient internal pathway is usually associated with balance and helps geckos sense vibrations traveling through media such as the ground or water.”

“This pathway is present in amphibians and fish, and has now been shown to be conserved in lizards.”

“Our findings reveal how the auditory system evolved from being visible in fish to being visible in land animals, including humans.”

In their research, Professor Kerr and colleague Dr. Dawei Han, a postdoctoral fellow at the University of Maryland, focused on: Tokay gecko (gecko gecko).

They discovered that the gecko’s saccule can sense weak vibrations in the 50 to 200 Hz range. This is a much lower spectrum than what geckos can normally hear.

This indicates that the saccule serves a different, but complementary, function to the gecko’s normal auditory system.

Geckos can hear sounds in the air, but many other reptiles do not have this ability.

“Discovery of the role of the saccule in gecko hearing may lead to a better understanding of communication and behavior in other animals previously thought to have limited hearing ability,” said Dawei of the University of Maryland.・Dr. Han said.

“Many snakes and lizards were thought to be ‘dumb’ or ‘deaf’ in the sense that they could not make or hear sounds very well.”

“But it turns out that animals could potentially be using this sensory pathway to communicate via vibrational signals. This has revolutionized the way scientists think about animal perception as a whole. Ta.”

The existence of this common sensory pathway in modern reptiles provides a unique window into the evolutionary history of vertebrate sensory systems, suggesting that the transition from aquatic to terrestrial environments may be more complex than previously thought. This suggests that gradual changes in auditory mechanisms are likely involved.

Although these discoveries are not directly related to human hearing, researchers believe there is always more than meets the eye – in this case, the ears.

“Think about going to a live rock concert,” Professor Kerr says.

“The sound is so loud that you can feel your whole head and body vibrating in the sound field.”

“You don’t just hear music, you can feel it. This sensation suggests that the human vestibular system may be stimulated during loud concerts, which This means that the sense of balance may also be closely related.

of findings Published in a magazine current biology.

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Dawei Han & Catherine E. Kartkay The gecko’s auditory pathway for sensing vibrations. current biologypublished online on October 4, 2024. doi: 10.1016/j.cub.2024.09.016