The victory squeal of dolphins and white whales on the surface and at 100 m or more in depth.

Abstract

After seizing a fish, small odontocetes often produce a rapid series of pulses that we call a ‘‘Victory squeal.’’ Animals trained to dive to depth and turn off a switch that was emitting a continuous tone [S. H. Ridgway etal., Science 166, 1651–1654; Can. J. Zool. 62, 2349–2351] made the victory squeal (Vs) within 1 s of tone termination (reinforcement signal or Sr). When dolphins (Tursiopstruncatus) or white whales (Delphinapterusleucas) were trained for other tasks, a Vs was commonly produced after the Sr (in these cases Sr was a whistle, tone, or underwater buzzer activated by the trainer for correct responses). At a depth of 100 m or more, Vs peak frequency of the white whale was lower than at the surface (p<0.001), while pulse repetition rate was higher at depth (p<0.05). Vs averaged 14.2-kHz peak frequency, 7.14-kHz, 3-dB bandwidth, and 247 pps at depth. At the surface, values were 29.3 kHz, 15.30-kHz, 3-dB bandwidth, and 179 pps (n=10 at surface, 10 at depth). Dolphin Vs latency after Sr was 560±192 ms (n=179). White whale Vs latency was 796±170 ms (n=104). Vs latency was shorter with higher amplitude of the Sr.