Characteristics of short-finned pilot whale clicks recorded in the far-field and by dorsally-attached tags. (a) Waveform of a click recorded in front of a pilot whale and close to the acoustic axis at 530 m depth. (b) Spectra of 30 clicks recorded close to the acoustic axis of a pilot whale (256 pt FFT). The dashed line indicates the combined ambient and system noise floor. (c) Waveform of a click recorded by a dorsally-attached tag (note the longer time scale compared to panel a). (d) The RMS amplitude (1 ms averages) in dB of 20 pilot whale regular clicks recorded by a dorsally-attached tag. All clicks were recorded with 192 kHz sampling rate. Decibels are with respect to an arbitrary reference.