Fig. 3. Effect of dominance status on mean electric organ discharge (EOD) duration (error bars ± 1 S.E.M.) of freely interacting female–female (A), male–male (B) and mixed-sex (C) pairs of Gnathonemus petersii (N=5 fish per group). EOD duration increased in all groups during interaction, with most of the increase occurring in dominant fish. The horizontal bar spanning days 4–8 represents the duration of interaction.