Analysis of bats’ gaze and flight control based on the estimation of their echolocated points with time-domain acoustic simulation

Abstract

Bats detect objects by echolocation. With those echoes, they can describe the shape of objects as well as position, and then approach or avoid them. To reveal which part of objects bats gaze at, we simulated the echoes that bats hear, and estimate the bats’ echolocated points by time-domain 2D-acoustic-simulation based on the behavioral data during obstacle-avoiding flight. First, we constructed a microphone array system in an experimental chamber and attached telemetry-microphones to Japanese horseshoe bats. With that measurement system, we obtained the timing, positions and directions of emitted pulses during obstacle-avoiding flight. Using these data, we simulated the echoes returning from the obstacles (acrylic boards) and investigated how the bats show spatial and temporal changes in the echolocated points of objects as they became familiar with the space. In a comparison between before and after the habituation in same obstacle layout, there are differences in the wideness of echolocated points on objects. By flying same layout repeatedly, their echolocating field become narrower. This study suggests the help of acoustic simulation to understand the way bats see the world. [This research was supported by Scientific Research on Innovative Areas of JSPS, and the JST PRESTO program.]