Fig. 2. Responses of individual dolphins in chemical familiarity and cross-modal experiments.

Each line connects the response data for one individual. (A) Mean duration of open-mouth sampling by individual, showing that dolphins sample urine longer than water. (B) Mean duration of open-mouth sampling by individual, showing that dolphins sample urine from familiar conspecifics longer than urine from unfamiliar individuals. (C) Mean approach duration by individual, showing that most individuals approach matched cross-modal presentations longer than mismatched presentations. Numbers in parentheses represent the number of observations for each individual and each condition. M, male; F, female. Full boxplots representing variation in individual response times are available in the Supplementary Materials (figs. S1 to S3). Note that the difference in each of the three panels reflects statistically significant effects in the multivariate models. Means and SEs are given in Table 1.