Dolphin Air Sac Motion Measurements During Vocalization by Two Noninvasive Ultrasonic Methods

  • R. Stuart Mackay
Part of the NATO Advanced Study Institutes Series book series (volume 28)


Method one uses short pulses of 2 MHz sound in a sonar system. A probe on the subject’s head projects impulses downward or inward. Echoes from successively deeper structures return to the probe to brighten a downward moving spot on a cathod ray tube. The spot jumps back to the top of the display and moves slightly to the right for the next pulse. Traced from left to right (Fig. 1) is the time pattern of movement of a line of internal reflecting structures, all correctly laid out in relative depth within the animal. Instead of being held stationary, the probe can be angulated on a small waterfilled balloon (flexible coupling) to outline internal structures (form image) and thus achieve the desired aim for time recording.


Doppler Frequency Shift Sonar System High Frequency Sound Flexible Coupling Sonic Beam 
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  1. Mackay, R. S., 1966, Telemetering physiological information from within cetaceans, and the applicability of ultrasound to understanding in vivo structure and performance, in: “Whales, Dolphins, and Porpoises”, K. Norris, ed., U.C. Press, Berkeley.Google Scholar
  2. Mackay, R. S., Rumage, W. T., and Becker, A., 1977, Sound velocity in spermaceti organ of a young sperm whale, in: “Proc. Second Conference on Biology of Marine Mammals”, San Diego.Google Scholar

Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • R. Stuart Mackay

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