Do killer whale tail slaps generate cavitation?
Some of the single pulses found in the sounds of killer whale underwater tail slaps had waveforms and spectral characteristics very similar to those obtained from the sound pulses of snapping shrimp, which are produced by cavitations (Fig. 4A, inset from Versluis et al., 2000). Snapping shrimp produce broadband sounds containing frequencies beyond 200 kHz and with a peak frequency in the range of 2 5 kHz (Au and Banks, 1998). The high-speed recordings of killer whale tail slaps revealed that parts of the sound contained frequencies beyond 150 kHz, with peak frequencies below 10 kHz (Fig. 4B). Average source level measurements of cavitation made by snapping shrimps were between 183 191 dB (pp) re. 1 µPa at 1 m (Au and Banks, 1998). The fact that the average source levels measured from single pulses in underwater tail slaps presented here [186 dB (pp) re. 1 µPa at 1 m] were within this range further suggests a similarity between the sound production mechanism of killer whale tail slaps,
