Dear all,
We are pleased to announce the publication of the following paper
about the acoustic scanning behavior of pipistrelle bats:
Seibert A-M, Koblitz JC, Denzinger A, Schnitzler H-U (2013)
Scanning Behavior in Echolocating Common Pipistrelle Bats (Pipistrellus pipistrellus).
PLoS ONE 8(4):1-11.
doi:10.1371/journal.pone.0060752
Abstract
Echolocating bats construct an auditory world sequentially by analyzing successive pulse-echo pairs. Many other mammals
rely upon a visual world, acquired by sequential foveal fixations connected by visual gaze saccades. We investigated the
scanning behavior of bats and compared it to visual scanning. We assumed that each pulse-echo pair evaluation
corresponds to a foveal fixation and that sonar beam movements between pulses can be seen as acoustic gaze saccades.
We used a two-dimensional 16 microphone array to determine the sonar beam direction of succeeding pulses and to
characterize the three dimensional scanning behavior in the common pipistrelle bat (Pipistrellus pipistrellus) flying in the
field. We also used variations of signal amplitude of single microphone recordings as indicator for scanning behavior in
open space. We analyzed 33 flight sequences containing more than 700 echolocation calls to determine bat positions,
source levels, and beam aiming. When searching for prey and orienting in space, bats moved their sonar beam in all
directions, often alternately back and forth. They also produced sequences with irregular or no scanning movements. When
approaching the array, the scanning movements were much smaller and the beam was moved over the array in small steps.
Differences in the scanning pattern at various recording sites indicated that the scanning behavior depended on the
echolocation task that was being performed. The scanning angles varied over a wide range and were often larger than the
maximum angle measurable by our array. We found that echolocating bats use a ‘‘saccade and fixate’’ strategy similar to
vision. Through the use of scanning movements, bats are capable of finding and exploring targets in a wide search cone
centered along flight direction.
The full text/pdf can be downloaded from http://dx.plos.org/10.1371/journal.pone.0060752
Greetings,
Anna-Maria Seibert
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Dipl. Biol. Anna-Maria Seibert
University of Tuebingen
Institute for Neurobiology,
Animal Physiology
Auf der Morgenstelle 28
72076 Tuebingen
Germany
Tel: +49 (0)7071-2974839
Email: