Figure 4.

Acoustic features of rapping and ticking. The distribution of interclick intervals (A) in milliseconds and amplitudes (B) in decibels (dB at 1 V/μPa) for each call are illustrated for 804 raps from eight females (96–109 samples per animal) and 208 ticks from three females (99–236 samples per animal). (C) Fast Fourier transform analyses of three representative clicks (one per animal) from rapping and ticking; frequency is 0–3 kHz for each graph and relative amplitudes (y axis) are measured in millivolts. Recordings were obtained in the artificial pond.