Dear Marmam subscribers, The following paper has recently been published online in the Journal of the Acoustical Society of America. For a copy, you can check the journal website at http://link.aip.org/link/?JAS/129/449, or contact: chaka@wrc.kyoto-u.ac.jp . Echolocation signals of Heaviside's dolphins (Cephalorhynchus heavisidii) Tadamichi Morisaka, Leszek Karczmarski, Tomonari Akamatsu, Mai Sakai, Steve Dawson, Meredith Thornton, J. Acoust. Soc. Am. 129, 449-457 (2011) The abstract is as follows; Field recordings of echolocation signals produced by Heaviside's dolphins (Cephalorhynchus heavisidii) were made off the coast of South Africa using a hydrophone array system. The system consisted of three hydrophones and an A-tag (miniature stereo acoustic data-logger). The mean centroid frequency was 125 kHz, with a -3 dB bandwidth of 15 kHz and -10 dB duration of 74 µs. The mean back-calculated apparent source level was 173 dB re 1 µPap.-p.. These characteristics are very similar to those found in other Cephalorhynchus species, and such narrow-band high-frequency echolocation clicks appear to be a defining characteristic of the Cephalorhynchus genus. Click bursts with very short inter-click intervals (up to 2 ms) were also recorded, which produced the "cry" sound reported in other Cephalorhynchus species. Since inter-click intervals correlated positively to click duration and negatively to bandwidth, Heaviside's dolphins may adjust their click duration and bandwidth based on detection range. The bimodal distribution of the peak frequency and stable bimodal peaks in spectra of individual click suggest a slight asymmetry in the click production mechanism. URL: http://link.aip.org/link/?JAS/129/449 DOI: 10.1121/1.3519401 Permalink: http://dx.doi.org/10.1121/1.3519401 =========================================== Tadamichi MORISAKA, Ph.D. Assistant Professor Wildlife Research Center of Kyoto University 3F, 2-24, Tanaka-Sekiden-cho, Sakyo-ku, Kyoto 606-8203, Japan Tel: 075-771-4388; Fax: 075-771-4394 chaka@wrc.kyoto-u.ac.jp http://www23.atwiki.jp/cetacea http://www.wrc.kyoto-u.ac.jp/ ===========================================