Animal Sonar pp 809-813 | Cite as

Sonar Discrimination of Metallic Plates by Dolphins and Humans

  • Whitlow W. L. Au
  • Douglas W. Martin
Part of the NATO ASI Science book series (NSSA, volume 156)


In the first Animal Sonar Systems symposium held in Frascati, Italy, Evans and Powell (1967) demonstrated that a blind-folded echolocating dolphin could discriminate the composition and thickness of metallic plates. Mackay (1967) orginally suggested this experiment to test if a dolphin could detect phase differences. An example of a typical sonar run showing the animal’s position at 1 s intervals is presented on the left side of Fig. 1. Weisser, et al. (1967) examined the plates by insonifying them at normal incident angle using simulated dolphin echolocation signals. No obvious differences between echo waveforms were observed. Fish et al. (1976) demonstrated that instrumented human divers wearing a helmet with a sending and two receiving transducers could perform the discrimination task as well as or better than the dolphin. Broadband simulated dolphin clicks with energy centered at 60 kHz were projected and the echoes time-streched by a factor of 128 before presentation to the divers.


Incident Angle Copper Plate Matched Filter Metallic Plate Trap Wave 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Au, W. W. L., and Synder, K. J., Long-range Target Detection in Open Waters by an Echolocating Atlantic Bottlenose Dolphin (Tursiops truncatus, J. Acoust. Soc. Am., 68:1077–1084.Google Scholar
  2. Evans, W. E., and Powell, B. A., 1967, Discrimination of Different Metallic Plates by an Echolocating Delphinid, in “Animal Sonar Systems: Biology and Bionics”, R. G. Busnel, ed., Laboratoire de Physiologie, Jouy-en-Josas, 78, France, pp. 363–382.Google Scholar
  3. Fish, J. F., Johnson, C. S., and Ljungblad, D. K., 1976, Sonar Target Discrimination by Instrumented Human Divers, J. Acoust. Soc. Am., 59: 602–606.PubMedCrossRefGoogle Scholar
  4. Mackay, R. S., 1967, Experiments to Conduct in Order to Obtain Comparative Results, in “Animal Sonar Systems: Biology and Bionics”, R.G.Busnel, ed., Laboratoire de Physiologie, Jouy-en-Josas, 78, France, pp. 1173–1196.Google Scholar
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Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

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

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