Antitragus Suppresses Fundamental Harmonic Pulse in a Horseshoe Bat, Rhinolophus Sinicus

Abstract

The biosonar system of bats utilizes physical baffle shapes around the sites of ultrasound reception for diffraction-based amplitude modulation. Bat antitragus has been hypothesized to affect the bat biosonar. Using numerical methods, we show that the antitragus of a Chinese horseshoe bat has an effect on increasing the acoustic near field as well as enhancing the reflection coefficient of the external ear. The simulation result provides a direct link between the biosonar signal and the morphological structure. The underlying physical mechanism suggested by the properties of the effect is that standing waves are produced between the pinna and antitragus.