Fig. 3. The effect of experience on urine release: percentage of time urine is released by winners (filled columns) and losers (open columns) during first (N=16), second (N=15) and third (N=8) fights of winners and spontaneously (Spont.) (N=39). Values are means +1 S.E.M. Asterisks denote significant differences between winner and loser (^**P<0.01, ^*P<0.05; multi-way ANOVA for repeated measures). Crayfish are more likely to release urine in a fight than spontaneously (P<0.01; paired t-test). No difference was found in urine release for winners or for losers between first, second and third fights.