Echolocation Signals of the Atlantic Bottlenose Dolphin (Tursiops truncatus) in Open Waters

  • Whitlow W. L. Au
Part of the NATO Advanced Study Institutes Series book series (volume 28)


A wide variety of echolocation experiments performed with the Atlantic bottlenose dolphin (Tursiops truncatus) have indicated that these dolphins possess a highly sophisticated and adaptive sonar system. Results of discrimination experiments have shown that Tursiops can detect a 10% difference in the diameter of metallic spheres (Norris, Evans, Turner, 1967), material composition and thickness differences as small as 0.1 cm in metallic discs (Evans and Powell, 1967), differences between plates shaped as circles, triangles and squares independent of their cross sectional areas, as well as a 6% change in the diameter of the circles (Barta and Evans, 1970; Fish, Johnson, and Ljungblad, 1976), and a 0.8 dB difference in the target strength of corprene cylinders (Evans, 1973). Murchison and Penner (1975) have demonstrated detection ranges of 72.2 m for a 2.54-cm diameter solid steel sphere and 76.8 m for a 7.6-cm diameter water-filled sphere. Range resolution capabilities of 0.9, 1.5 and 2.8 cm for target ranges of 1,3, and 7 m have been reported by Murchison (1976). Nachtigall, Murchison and Au (1978) reported on the ease with which a Tursiops could discriminate between foam cubes and cylinders of different sizes.


Peak Frequency Sound Pressure Level Bottlenose Dolphin Beam Pattern Target Strength 
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Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • Whitlow W. L. Au
    • 1
  1. 1.Naval Ocean Systems CenterKailuaUSA

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