Fig. 4. Plots of mean lateral excursion ± s.e.m. of the dorsal tip (circles), fork (triangles) and ventral tip (squares) of the tail fin during kick-and-glide (A, red), braking (B, white) and backing (C, green) maneuvers. A solid line connects the values for fork of the tail throughout the tail beat to compare against dorsal and ventral tail tip excursion. The dashed zero line indicates the mean direction of travel.