Visualization of bat “echo space” using acoustic simulation

Abstract Behavioral experiments with acoustic measurements have revealed the intriguing strategies of flight navigation and the use of ultrasound by echolocating bats in various environments. However, the echolocation behavior of bats has not been thoroughly investigated in regard to the environment they perceive via echolocation because it is technically difficult to measure all the echoes that reach the bats during flight, even with the conventional telemetry microphones currently in use. Therefore, we attempted to reproduce the echoes of bats during flight by combining acoustic simulation and behavioral experiments with acoustic measurements. As a result, we visualized the spatiotemporal changes in the echo incidence points detected by bats during flight, which enabled us to investigate the “echo space” revealed through echolocation. In addition, we could observe how the distribution of visualized echoes concentrated at the obstacle edges after the bats became more familiar with their environment. Furthermore, our results indicate that the direction of preceding echoes affects the turn rates of the bat's flight path, revealing their original echolocation behavior.