High Intensity Narwhal Clicks
The hypothesis that some odontocetes use their sonar not only to find prey, but also to debilitate it (Norris and Møhl, 1983) requires that odontocetes produce sound pressures in excess of 230 dB re. 1 μPa (Zaegaesky, 1987; Hubbs and Rechnitzer, 1972). While maximum source levels1 (SL) of clicks recorded from trained Tursiops (Au et al., 1974) and Delphinapterus (Au et al., 1987) are only a few dB short of this value, there is a gap of 50 to 120 dB between the debilitation threshold and the SL’s reported for odontocete clicks in nature (Levenson, 1974; Watkins and Schevill, 1974; Watkins, 1980a, b).
KeywordsSource Position Sperm Whale Time Domain Measure Acoustical Axis Echolocation Signal
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