Foraging in proximity to humans can shape social centrality in wild dolphins

Some marine animals can form social groups to detect and exploit patchy ocean resources efficiently, which can be beneficial during periods of low prey availability. However, human-provided food sources in coastal areas can reduce the necessity for cooperative hunting, potentially weakening social bonds among marine animals adapted to human-disturbed environments. In Sarasota Bay, Florida, some members of the long-term resident bottlenose dolphin ( Tursiops truncatus ) community engage in human-centric foraging, especially following environmental changes, such as intense harmful algal blooms that deplete natural prey. Here, we model how varying levels of human interaction with dolphins’ foraging behaviors influence their social network structure and evaluate correlations among behavior changes and harmful algal blooms. Using Bayesian inference and network analysis on a 18-yr comprehensive dataset of the Sarasota dolphin community, we compared the network positions of dolphins that engaged in human-centric tactics to those observed using only natural foraging tactics. We found that the type of human-centric behavior had different effects on sociality. More direct, risky interactions with humans caused individuals to become less connected with other dolphins, while human-centric foraging away from humans increased sociality. These findings have implications for understanding the long-term impact of human interactions on the social cohesion of wildlife communities.