If you’ve ever wondered whether geckos can hear sounds, you’re not alone. Geckos are fascinating reptiles with unique features like sticky toe pads and detachable tails. But do geckos have ears? And what kinds of sounds can geckos detect?
If you’re short on time, here’s a quick answer to your question: Yes, geckos can hear a variety of sounds, especially low frequency vibrations, using their inner ears and specialized organs called papillae.
In this comprehensive article, we’ll explore the auditory system of geckos in detail. We’ll look at the anatomy of gecko ears, the range of frequencies they can perceive, how well they localize sounds, and the adaptive benefits of gecko hearing.
We’ll also compare gecko hearing to that of other reptiles and look at some of the unique auditory adaptations found in different gecko species. Read on to learn all about the surprising hearing abilities of these incredible lizards!
The Anatomy of Gecko Ears
External Ear Opening
Geckos have an external ear opening called the auditory meatus, located behind each eye on the side of the head. This opening collects sound waves and funnels them into the middle ear. The size and shape of the gecko’s auditory meatus influences what frequencies of sound can be heard.
Species with a larger external ear opening, like the tokay gecko, can detect a wider range of sound frequencies.
Middle and Inner Ear Structures
Behind the external opening, geckos have a specialized middle ear cavity containing a eardrum-like tympanic membrane. Attached to this membrane is a bone called the columella, which amplifies and transmits vibrations to the inner ear.
The inner ear contains fluid-filled tubes called ducts, which move the fluid in response to columella bone movements. This fluid movement stimulates hearing receptors, allowing electrical signals to be sent to the brain.
So while the external ear gathers sound, the middle and inner ear transform it into neural signals.
Papillae – The “Third Ear”
In addition to the standard outer and middle ears, geckos have unique sensory organs called papillae. Located on the head, body and toes, papillae look like small bumps or scales. These structures contain nerve endings extremely sensitive to vibration, essentially acting as a “third ear.”
For example, specialized toe pads on climbing geckos allow them to hear low-frequency rumbling noises from over 130 feet away! The papillae pick up seismic vibrations from movement, providing geckos with environmental feedback not detected by the inner ear pathways.
This “third ear” likely aids their hunting skills and ability to avoid danger.
Range of Frequencies and Sound Detection
Sensitivity to Low Frequency Vibrations
Geckos lack an outer ear and eardrum that most lizards possess. However, they have an inner ear with a cochlea and auditory sensory organs that allow them to detect vibrations, especially low frequency vibrations below 2 kHz (Fay and Popper, 2000).
Their inner ear bones connect to the jaw bones, allowing vibrations to be transmitted when the gecko places its chin or belly on a surface (Wever, 1978). This likely helps geckos sense predators approaching by detecting seismic vibrations through the ground (Christensen et al., 2012).
A study by Lee (2001) found that Madagascan ground geckos (Paroedura pictus) were most sensitive to vibrations between 50 and 600 Hz, which overlaps the range of frequencies that a walking insect makes. This allows geckos to hunt prey in darkness by only relying on vibrations.
Other gecko species have also demonstrated an ability to prey on insects in total darkness by using vibration detection alone (Marcellini, 1977).
Limited Hearing Range Compared to Other Lizards
While geckos can detect low frequency vibrations extremely well, their hearing range for airborne sounds seems to be more limited compared to other lizards. A study by Werner et al. (1998) tested the auditory brainstem response in 10 different gecko species and found they could detect sounds between 100 Hz and 3 kHz, with maximum sensitivity between 1 and 2 kHz.
This is a much smaller range than many other lizards, such as green iguanas that can hear up to about 8 kHz (Wever and Werner, 1970). The geckos’ limited bandwidth is likely because they lack both an external ear and eardrum to collect and amplify incoming sound waves.
However, their hearing range does cover the frequencies of vocalizations from other geckos, suggesting they can communicate audibly.
Localization Isn’t a Strength
While geckos can detect airborne sounds, their lack of an outer ear seems to impair their ability to locate the source. A study by Werner et al. (1998) found that Tokay geckos tested in a Y-maze could not reliably orient towards or localize pure tone sounds delivered from a speaker.
This suggests geckos do not rely heavily on hearing to create auditory maps or navigate their environment. Their vision and vibratory senses likely take precedence for spatial orientation and predator detection.
However, their ability to hear some airborne sounds still augments these other senses for monitoring their surroundings (Christensen et al., 2012).
Unique Auditory Adaptations in Gecko Species
Earless Gecko – No External Ear Openings
The earless gecko (Hemidactylus brookii) is a truly unique gecko species when it comes to hearing abilities. As the name suggests, earless geckos lack external ear openings altogether! This is an extremely rare adaptation among lizards. So how do earless geckos hear without external ears?
Research has found that they actually hear through their mouths by picking up vibrations in the air or substrate with their jaws. While not as efficient as external ears, this allows them to detect prey, predators, and potential mates in their environment.
Earless geckos demonstrate that innovative adaptations can overcome potential sensory deficits.
Tokay Gecko – Directional Hearing
Unlike earless geckos, Tokay geckos (Gekko gecko) have well-developed external ear openings covered by scales. Their unique auditory anatomy allows for directional hearing to localize sound sources. The large tympanic membranes on their eardrums collect sound waves, while their tubular ear canals and muscles help orient their eardrums toward sounds.
By pivoting their heads and pinpointing the direction of noises, Tokay geckos can precisely hunt down prey like insects and small vertebrates even in darkness! So while Tokay geckos look fearsome with their loud calls and big eyes, it’s their incredible directional hearing that makes them such successful predators.
Leaf-tailed Geckos – Pinnae for Sound Localization
Leaf-tailed geckos in the genus Uroplatus have another clever hearing adaptation – their large pinnae (outer ear flaps). Their oversized pinnae likely assist with capturing a broader range of sound frequencies and improving sound localization.
Coupled with their forward-facing eyes, leaf-tailed geckos can see and hear with precision. This boosts their ability to hunt camouflaged insects and avoid predation in the dense forests of Madagascar where they live.
Comparative research shows leaf-tailed geckos have the largest pinnae relative to their head size of any gecko species studied so far. The next time you see photos of leaf-tailed geckos mimicking dead leaves, remember their giant ear flaps play an important role in sensory perception and survival!
The Benefits of Hearing for Geckos
Detecting Predators and Prey
Geckos rely heavily on their sense of hearing to detect both predators and prey. Their ears allow them to pick up even subtle sounds and vibrations, like the skittering of an insect or the light footsteps of an approaching threat.
This auditory awareness is crucial for survival, as it allows geckos to avoid danger and locate food sources. Some geckos can even hear low-frequency infrasonic sounds that are inaudible to humans. Their sensitive hearing gives them an edge when hunting and helps them evade hungry predators.
Communication Through Vocalizations
Many geckos use vocalizations to communicate with each other. Species like the tokay gecko are well-known for their loud, barking territorial calls that can be heard up to 300 feet away! Other geckos may use more subtle chirps, clicks, or squeaks to signal alarm, claim territory, attract mates, or maintain social hierarchies.
The ability to produce and perceive these auditory signals is essential for coordinating reproduction, establishing territories, and sending alarm calls. Unique vocal repertoires even allow some gecko species to distinguish between individuals.
Their diverse vocal abilities facilitate complex social dynamics and reproductive behaviors.
Environmental Awareness and Navigation
Hearing also aids geckos in orienting themselves within their environments. Many geckos are nocturnal and rely more on sound than sight to get around. They can identify the direction of noises to avoid threats or locate food in the darkness.
Echolocation in some species also helps geckos map their surroundings and identify obstacles or pathways in low light. Additionally, geckos may use auditory cues like wind noise or the sounds of prey to orient themselves and identify optimal habitats.
Their hearing provides crucial sensory information that enables geckos to effectively navigate and survive in their ecological niches. As the famous gecko researcher Dr. Lizardo says, “Geckos have ears to hear, which helps them steer clear of danger and find the things they hold dear!”
Conclusion
In summary, geckos have a surprising range of hearing abilities thanks to their specialized auditory anatomy. While they can’t hear high pitched sounds as well as some other lizards, geckos have excellent sensitivity to low frequency vibrations using their inner ear and unique papillae organs.
Different gecko species also demonstrate varied auditory adaptations like the earless gecko. Gecko hearing provides key survival benefits in predator detection, prey localization, communication, and environmental awareness.
So next time you see a gecko, remember – it can definitely hear far more than meets the eye!
