Uploaded August 2025 | Updated September 2026, 23 hours ago
Prof Catherine Carr
Abstract Title: Sound localization behavior in the Barking Gecko
Co-Authors: Michael Cherry; Jakob Christensen-Dalsgaard
Author affiliations: Univ Stellenbosch, Uni Southern Denmark
Abstract: Lizards have coupled, highly directional ears, but sound localization behavior has not been observed in this clade. We therefore examined orientation in male Barking geckos. Their calls serve both to attract females, and in male-male competition by enabling males to maintain exclusive space surrounding male burrows. Thus, there should be strong selection on males to orient towards the calls of conspecifics.
To examine sound localization in barking geckos, we measured their auditory brainstem responses to sound, laser vibrometry, anatomy and orientation at the Kuruman River Reserve, South Africa. ABRs were measured in a sound-insulated box, and directional responses to sound were recorded using a portable laser vibrometer. Interaural transmission was computed using local sound stimulation and laser vibrometry. Sound localization behavior was recorded on a video camera under infrared illumination. The camera was directed at the burrow mouths of calling geckos to record responses to recorded gecko calls played sequentially from eight Bluetooth speakers at 30˚ intervals around the burrow. Orientation responses were quantified from the video recordings.
Barking geckos are very sensitive to sound in a frequency range up to 10 kHz with peak sensitivity at 3 kHz. The ear is strongly directional from 2 to 4 kHz (the peak frequencies in their calls), where interaural transmission gain is close to 0 dB, showing strong interaural coupling. Behavioral analyses showed that geckos oriented to call playbacks with an accuracy of about 8°. The accuracy was highest from sounds from frontal angles and closer to 20° for the most lateral sound sources.
This first demonstration of sound localization in lizards should support further studies of their directional behavior and inform our understanding and modelling of directional sensitivity and neural processing of directional sound.
Prof Catherine Carr
Abstract Title: Sound localization behavior in the Barking Gecko
Co-Authors: Michael Cherry; Jakob Christensen-Dalsgaard
Author affiliations: Univ Stellenbosch, Uni Southern Denmark
Abstract: Lizards have coupled, highly directional ears, but sound localization behavior has not been observed in this clade. We therefore examined orientation in male Barking geckos. Their calls serve both to attract females, and in male-male competition by enabling males to maintain exclusive space surrounding male burrows. Thus, there should be strong selection on males to orient towards the calls of conspecifics.
To examine sound localization in barking geckos, we measured their auditory brainstem responses to sound, laser vibrometry, anatomy and orientation at the Kuruman River Reserve, South Africa. ABRs were measured in a sound-insulated box, and directional responses to sound were recorded using a portable laser vibrometer. Interaural transmission was computed using local sound stimulation and laser vibrometry. Sound localization behavior was recorded on a video camera under infrared illumination. The camera was directed at the burrow mouths of calling geckos to record responses to recorded gecko calls played sequentially from eight Bluetooth speakers at 30˚ intervals around the burrow. Orientation responses were quantified from the video recordings.
Barking geckos are very sensitive to sound in a frequency range up to 10 kHz with peak sensitivity at 3 kHz. The ear is strongly directional from 2 to 4 kHz (the peak frequencies in their calls), where interaural transmission gain is close to 0 dB, showing strong interaural coupling. Behavioral analyses showed that geckos oriented to call playbacks with an accuracy of about 8°. The accuracy was highest from sounds from frontal angles and closer to 20° for the most lateral sound sources.
This first demonstration of sound localization in lizards should support further studies of their directional behavior and inform our understanding and modelling of directional sensitivity and neural processing of directional sound.
