Fig. 3. Dive profile (A) and fluke rate (B) for a Ziphius. Vocal phase and buzzes are marked on the dive profile. The average fluke rate in 1 min intervals, measured by counting cyclic variations in the pitch signal from the tag, is shown in the lower panel. The fluke rate is high in the first minute of both deep and shallow dives but then drops markedly during the remainder of the descent. Ascents, in comparison, feature more steady fluking.