Uncovering the Hidden Hearing Talent of Geckos: A Sixth Sense Revealed by University of Maryland Biologists

University of Maryland biologists have made a groundbreaking discovery that challenges our understanding of animal hearing. In a study published in Current Biology on October 4, 2024, the researchers revealed that geckos possess a hidden sensory talent that allows them to detect low-frequency vibrations using a part of their inner ear called the saccule.

Traditionally, the saccule has been associated with maintaining balance and body positioning in animals. However, the researchers found that in geckos, this sensory pathway plays a crucial role in detecting vibrations that travel through mediums like the ground or water. This unique ability, described as a “sixth sense” by the researchers, complements the geckos’ normal hearing and enhances their perception of the world around them.

According to Catherine Carr, a Distinguished University Professor of Biology at UMD and co-author of the study, this discovery sheds light on the evolution of the auditory system in animals. The presence of this sensory pathway in geckos suggests that similar mechanisms may be present in other reptilian species, challenging existing ideas about how animal sensory systems have evolved over time.

The saccule in geckos can detect faint vibrations ranging from 50 to 200 Hz, a range that is below what geckos can typically hear through their ears. This indicates that the saccule serves a distinct yet complementary function to the geckos’ regular auditory system. The lead author of the study, Dawei Han, a postdoctoral researcher at UMD, believes that this discovery may lead to a better understanding of communication and behavior in reptiles previously thought to have limited auditory capabilities.

The researchers suggest that the existence of this shared sensory pathway in modern reptiles provides insights into the evolutionary history of vertebrate sensory systems. It indicates that the transition from aquatic to terrestrial environments likely involved more complex and gradual changes in hearing mechanisms than previously thought.

While the findings are not directly related to human hearing, the researchers believe that there may be implications for understanding the link between hearing and balance in mammals. They hope that further research into this sensory pathway could provide new insights into human hearing and balance disorders.

This research was supported by the National Institutes of Health (Grant No. R01DC019341). The researchers, Carr and Han, are optimistic that uncovering these hidden mechanisms in animals will lead to a deeper understanding of how different species perceive and interact with their environments, potentially offering new insights into human sensory experiences.