Fig. 1 (A) Non-dimensional fluke-beat amplitude, A/L, as a function of length-specific swimming speed, U/L, where A is the peak-to-peak fluke-beat amplitude, L is the body length and U is the swimming speed. (B) Non-dimensional fluke-beat amplitude, A/L, as a function of fluke-beat frequency f (Hz), where A is the peak-to-peak fluke-beat amplitude and L is the body length. Symbols indicate particular cetacean species: Tursiops truncatus (solid red circles), Pseudorca crassidens (open green squares), Orcinus orca (solid blue triangles), Globicephala melaena (blue crosses), Lagenorhynchus obliquidens (solid blue diamonds), Stenella frontalis (open brown diamonds) and Delphinapterus leucas (solid black triangles).