The juvenile period is a challenging life history stage, especially in species with a high degree of fission-fusion dynamics, such as bottlenose dolphins, where maternal protection is virtually absent. Here, we examined how juvenile male and female bottlenose dolphins navigate this vulnerable period. Specifically, we examined their grouping patterns, activity budget, network dynamics, and social associations in the absence of adults. We found that juveniles live in highly dynamic groups, with group composition changing every 10 minutes on average. Groups were generally segregated by sex, and segregation was driven by same-sex preference rather than opposite-sex avoidance. Juveniles formed strong associations with select individuals, especially kin and same-sex partners, and both sexes formed cliques with their preferred partners. Sex-specific strategies in the juvenile period reflected adult reproductive strategies, in which the exploration of potential social partners may be more important for males (which form long-term alliances in adulthood) than females (which preferentially associate with kin in adulthood). Females spent more time alone and were more focused on foraging than males, but still formed close same-sex associations, especially with kin. Males cast a wider social net than females, with strong same-sex associations and many male associates. Males engaged in more affiliative behavior than females. These results are consistent with the social bonds and skills hypothesis and suggest that delayed sexual maturity in species with relational social complexity may allow individuals to assess potential associates and explore a complex social landscape without the risks associated with sexual maturity (e.g. adult reproductive competition; inbreeding).
juvenile_joinleaves.csv - counts of join/leave events for juvenile focals, for calculating juvenile fission-fusion rate. For use with FissionFusionRate.R.
juvenile_events.csv - behavioral events during juvenile focal follows, for calculating juvenile behavioral event rates. For use with FocalFollows.R.
juvenile_pointsamples.csv - behavioral point samples during juvenile focal follows, for calculating juvenile activity budgets. For use with FocalFollows.R.
juvenile_jlevents.csv - list of join/leave events between juveniles, for calculating Hinde's index. For use with HindesIndex.R.
juvenile_surveys_SSAS.csv - counts of juvenile males and juvenile females in surveys in which no adults were present, for calculating Sexual Segregation and Aggregation Statistic. For use with SexSegregation.R.
juvenile_surveys.csv - survey data from surveys containing at least 1 juvenile, for calculating summary statistics (e.g. mean group sizes) and plotting Figures 1 and 2. For use with SummaryStats.R.
juvenile_surveys_activity.csv - primary activity in all-juvenile surveys, for calculating juvenile survey activity budgets. For use with SurveyActivityBudget.R.
real_network_metrics_20190930.csv - observed social network metrics of 140 juvenile individuals, for spatially explicit null model analysis. For use with SignificanceTestingAndFigures.R. This csv file is generated by the script SENM.R; raw data available upon request.
all_random_metrics_20190930.csv - simulated social network metrics of 140 juvenile individuals, for spatially explicit null model analysis. For use with SignificanceTestingAndFigures.R. This csv file is generated by the script SENM.R; raw data available upon request.
National Science Foundation, Award: 0847922
National Science Foundation, Award: 0820722
National Science Foundation, Award: 9753044
National Science Foundation, Award: 0316800
National Science Foundation, Award: 0918308
National Science Foundation, Award: 0941487
National Science Foundation, Award: 1559380
National Science Foundation, Award: 1755229