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dc.contributor.authorZimmer, Walter M. X.
dc.contributor.authorTyack, Peter L.
dc.contributor.authorJohnson, Mark P.
dc.contributor.authorMadsen, Peter T.
dc.date.accessioned2008-08-27T16:20:54Z
dc.date.available2008-08-27T16:20:54Z
dc.date.issued2005-03
dc.identifier.citationJournal of the Acoustical Society of America 117 (2005): 1473-1485en
dc.identifier.urihttp://hdl.handle.net/1912/2361
dc.descriptionAuthor Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 117 (2005): 1473-1485, doi:10.1121/1.1828501.en
dc.description.abstractThe three-dimensional beam pattern of a sperm whale (Physeter macrocephalus) tagged in the Ligurian Sea was derived using data on regular clicks from the tag and from hydrophones towed behind a ship circling the tagged whale. The tag defined the orientation of the whale, while sightings and beamformer data were used to locate the whale with respect to the ship. The existence of a narrow, forward-directed P1 beam with source levels exceeding 210 dBpeak re: 1 µPa at 1 m is confirmed. A modeled forward-beam pattern, that matches clicks >20° off-axis, predicts a directivity index of 26.7 dB and source levels of up to 229 dBpeak re: 1 µPa at 1 m. A broader backward-directed beam is produced by the P0 pulse with source levels near 200 dBpeak re: 1 µPa at 1 m and a directivity index of 7.4 dB. A low-frequency component with source levels near 190 dBpeak re: 1 µPa at 1 m is generated at the onset of the P0 pulse by air resonance. The results support the bent-horn model of sound production in sperm whales. While the sperm whale nose appears primarily adapted to produce an intense forward-directed sonar signal, less-directional click components convey information to conspecifics, and give rise to echoes from the seafloor and the surface, which may be useful for orientation during dives.en
dc.description.sponsorshipThis work was funded by grants from the Office of Naval Research Grants N00014-99-1-0819 and N00014-01-1-0705, and the Packard Foundation.en
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.publisherAcoustical Society of Americaen
dc.relation.urihttp://dx.doi.org/10.1121/1.1828501
dc.subjectBioacousticsen
dc.subjectBiocommunicationsen
dc.subjectArray signal processingen
dc.subjectEchoen
dc.subjectHydrophonesen
dc.subjectMultidimensional signal processingen
dc.subjectUnderwater sounden
dc.subjectSonar signal processingen
dc.titleThree-dimensional beam pattern of regular sperm whale clicks confirms bent-horn hypothesisen
dc.typeArticleen
dc.identifier.doi10.1121/1.1828501


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