Fig. 8.

Relationship between tail beat amplitude and head angle. (A) In free-stream swimming, head angle increased linearly with tail beat amplitude (y=0.70x, r²=0.56, P<0.05, N=8). This indicates that when the tail beat amplitude was at one extreme, the head angle was also maximally at that side (i.e. in phase). (B) In contrast, during Kármán gaiting the tail beat amplitude lagged behind head angle by ~72 deg (r²=0.70, P<0.05, N=8).