The study of aggression and affiliation motifs in bottlenose dolphins’ social networks

Abstract

Networks in biology have provided a powerful tool to describe and study very complex biological processes and systems such as animal societies. Social network analysis allows us to assess different processes occurring in animal groups. In the current study, we use this approach to investigate how conflict dynamics and post-conflict interactions shape the social networks of groups of captive bottlenose dolphins. We first examined temporal changes and aggression-affiliation motifs in the observed dolphins’ network structure. Using the results of the previous analysis, we built two models that simulate the dynamics of aggression and affiliation in a small dolphin group. The first model is based only on the observed statistics of interactions, whereas the second includes post conflict memory effects as well. We found that the resulting social networks and their most common motifs matched the association patterns observed in wild and captive dolphins. Furthermore, the model with memory was able to capture the observed dynamics of this group of dolphins. Thus, our models suggest the presence and influence of post-conflict behaviors on the structure of captive dolphins’ social networks. Therefore, the network approach reveals as an effective method to define animal social networks and study animal sociality. Finally, this approach can have important applications in the management of animal populations in captive settings.

Dolphin-WET—Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care

“…For example, dolphins engaged in more social interactions and exhibited high group activity rates when new enrichment devices were regularly provided [ 26 ]. Recent studies have pointed out several other promising potential welfare indicators: the behavioural diversity index, which refers to the frequency and variability of species-specific behaviours displayed by an individual, suggests that high behavioural diversity may indicate a positive welfare state [ 3 , 27 ]; predictable training schedules [ 24 ] linked to anticipatory behaviour (another potential welfare indicator) [ 28 , 29 ]; the dolphins’ willingness to participate in training activities [ 15 , 30 , 31 ]; post-conflict behaviours that structure dolphins’ social networks [ 32 ]; and swimming features as potential indicators of the dolphins’ emotional states [ 33 ]. Despite all these studies, to date, there is still no individual-based welfare assessment tool specifically developed for bottlenose dolphins under human care that includes a wide range of animal- and resource-related indicators.…”