Fig. 3.
Echolocation and movement during prey capture attempts in Sowerby's beaked whale. (A) Waveforms of three buzz clicks recorded from untagged whales near a tagged whale (denoted by different colours). (B) Spectral density of the same three clicks. Variability in the spectra suggests that these clicks were probably not recorded close to the biosonar acoustic axis (off-axis). (C) Accelerometer data recorded during a sequence of buzzes produced by the tagged whale, at about 1020 m depth. The start times of buzzes are indicated by the black triangles. Sharp transients occur in the x and z accelerometer axes during the buzzes, and rapid cyclic variations in the same axes prior to each buzz indicate energetic swimming. (D) Echogram during a typical buzz (the 5th buzz in C) showing a steady approach speed of nearly 2 m s−1. The target is first visible in the echogram 6 s before the start of the buzz at a range of 15 m. The buzz begins when the target is at about 5 m range and there is no indication of an escape response by the targeted organism.