The brightly spotted tokay gecko (Gekko gecko) appears to have a hidden sensory talent akin to a “sixth sense”. The geckos can use a part of the inner ear associated with maintaining balance and body positioning called the saccule to detect low-frequency vibrations. This special sense plays a complementary role in their normal hearing and the way they sense their world. It may also be present in other reptilian species. The findings are detailed in a study published October 4 in the journal Current Biology.
“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,” study co-author and University of Maryland biologist Catherine Carr said in a statement. “This pathway exists in amphibians and fish, and now it’s proven to be preserved in lizards as well. Our findings shed light on how the auditory system evolved from what you see in fish to what you see in land animals including humans.”
Geckos are masters of balance and can cling to walls with the sticky hairs that line their feet and toe pads. Internally, they use the saccule, which can detect faint vibrations that range from 50 to 200 Hz. This spectrum is well below what geckos can usually hear with their ears alone. According to the team, this means that the saccule likely serves a distinct but complementary function to their auditory system.
To take a look at this pathway, the team observed how their auditory system responded to various stimuli in a lab. Here, they saw how the saccule appears to help them pick up these sounds.
Unlike other reptiles, geckos can actually hear airborne sounds, or sounds that travel through the air in the form of sound waves, not just their vibrations. Figuring out the saccule’s role in how geckos hear may lead to a better understanding of communication and behavior in other animals that were…
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