[MARMAM] New paper on harbor porpoise echolocation

Jens Koblitz jens.koblitz at gmail.com
Thu Mar 15 14:16:57 PDT 2012


Dear colleagues,

I am pleased to announce the publication of the following paper in the 
Journal of the Acoustical Society of America:

Koblitz, J.C., M. Wahlberg, P. Stilz, P.T. Madsen, K. Beedholm, and 
H.-U. Schnitzler (2012).
Asymmetry and dynamics of a narrow sonar beam in an echolocating 
harborporpoise.
Journal of the Acoustical Society of America. 131 (3), 2315-2324

URL:http://link.aip.org/link/?JAS/131/2315
DOI: 10.1121/1.3683254


Abstract:

A key component in the operation of a biosonar system is the radiation 
of sound energy from the sound producing head structures of toothed 
whales and microbats. The current view involves a fixed transmission 
aperture by which the beam width can only change via changes in the 
frequency
of radiated clicks. To test that for a porpoise, echolocation clicks 
were recorded with high angular resolution using a 16 hydrophone array. 
The beam is narrower than previously reported (DI = 24 dB) and slightly 
dorso-ventrally compressed (horizontal -3 dB beam width: 13°, vertical 
-3 dB beam width: 11°). The narrow beam indicates that all smaller 
toothed whales investigated so far have surprisingly similar beam widths 
across taxa and habitats. Obtaining high directionality may thus be at 
least in part an evolutionary factor that led to high centroid 
frequencies in a group of smaller toothed whales emitting narrow band 
high frequency clicks. Despite the production of stereotyped narrow band 
high frequency clicks, changes in the directionality by a few degrees 
were observed, showing that porpoises can obtain changes in sound radiation.

Please feel free to contact me for a pdf copy.

With kind regards,
Jens Koblitz

Jens.Koblitz at uni-tuebingen.de

Biosonar Lab
Animal Physiology
Insitue for Neurobiology
University of Tuebingen

Auf der Morgenstelle 28
D-72076 Tuebingen
Germany

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