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J Acoust Soc Am. 2014 Dec;136(6):3389. doi: 10.1121/1.4898428.

Rapid shifts of sonar attention by Pipistrellus abramus during natural hunting for multiple prey.

Author information

1
Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara-Miyakotani Kyotanabe, Kyoto 610-0321, Japan.
2
Brain Science Institute, RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan.
3
Faculty of Life and Medical Sciences, Bio-Navigation Research Center, Doshisha University, 1-3 Tatara-Miyakotani Kyotanabe, Kyoto 610-0321, Japan.
4
Department of Neuroscience, Brown University, 185 Meeting Street, Box G-LN, Providence, Rhode Island 02912.

Abstract

Flight paths of echolocating Japanese house bats, Pipistrellus abramus, were tracked during insect hunting in a natural setting using a 32-microphone array. The array surrounded the foraging area, locating each bat, and determined the directional aim of the sonar beam. Successive interceptions, indicated by feeding "buzzes" and post-buzz pauses, occurred singly at intervals from over 20 s down to multiple interceptions at 2-3 s intervals. Bats flew on looping, curved paths. Turning radius tightened as rate of interceptions increased, keeping the bat in a smaller area of higher capture density. Broadcast beams shifted direction during search, often alternating between the direction of flight and another direction where, moments later, the next interception would occur. Broadcasts also shifted direction between the current target and the next target. Bats time-share biosonar attention between objects by alternating acoustic gaze. During search, most interpulse intervals (IPIs) were 70-120 ms, but bats interspersed long IPIs up to 200 ms when the rate of interception was low and flight paths followed broad curves. Mathematical modeling of search paths demonstrated that circular flight-paths with occasional long IPIs would be more effective for target search than either random, correlated random, or linear flights.

PMID:
25480083
DOI:
10.1121/1.4898428
[Indexed for MEDLINE]

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