Fig. 2. Variability between trajectories. (A) Three consecutive 5-min recordings obtained from Fish 2 during its first visit to the tank. (B) Three consecutive 5-min trajectories from Fish 5 recorded during its first visit to the tank. Differences between Fish 2 and Fish 5 are distinct. (C) Three consecutive 5-min recordings from Fish 5 during its fifth visit to the tank. Visual comparison of B and C suggests the presence of a high degree of intra-individual variability, which was confirmed quantitatively with the nonlinear measures.