Echolocation strategy for multiple target-preys by foraging bats investigated by field measurement and mathematical modeling

Using a super microphone-array system, 3-D flight paths of echolocating Japanese house bats, Pipistrellus abramus, across whole foraging area were successfully measured in the field, together with the directional aim of their sonar beams. Sonar sounds were sometimes rapidly alternated between its direction and other one or two particular directions during search phase. Especially, when the bats consecutively captured multiple insect preys, their emissions were directed toward not only the current target prey and also the next target. These suggest that the bats process multiple echo streams by time-sharing manner and plan the flight path to efficiently capture multiple target preys. In order to examine whether the bats select the efficient flight path to consecutively capture multiple targets, the bats' 3-D flight behavior while approaching two target preys was then modeled. The modeling analysis suggested that the echolocating bats select their flight paths to easily direct their sonar beams toward both targets. [This research was supported by the Aihara Project, the FIRST program from JSPS, initiated by CSTP, a Grant-in-Aid for Young Scientists (A) of JSPS, and the Murata Science Foundation.]