Data from: Individual foraging variation drives social organization in bottlenose dolphins

Identifying foraging variation within a population and assessing its
relationship with social structure is essential to increase knowledge
about the evolution of social systems. Here, we investigated individual
foraging variation in bottlenose dolphins and its potential influence on
their social organization. We used generalized affiliation indices and
applied social network analysis to data collected over 4 consecutive years
of research in a coastal area subject to significant use and pressure by
humans. Our findings revealed variation in foraging behavior among
individual bottlenose dolphins, which in turn shapes their social
organization. Our results indicated that individuals that frequently
foraged within human-altered areas (i.e., shellfish farms) exhibited
weaker Strength, Reach, and Affinity compared to others. These bottlenose
dolphins profit from a reliable and easily located food source which may
increase their energy intake and inter-individual competition. In
contrast, individuals that foraged less frequently within the shellfish
farms occupied a central position within the network and exhibited strong
associations. These individuals may benefit from increased cooperation and
reduced intragroup competition, thus increasing learning and
information-sharing, as they may face a patchy and irregular distribution
of prey. We also demonstrated that bottlenose dolphins preferred to
affiliate with other individuals with similar foraging strategies (i.e.,
homophily), which could promote, through time, a segregation of the
population into behaviorally distinct groups. These findings provide
valuable insight into the evolution of bottlenose dolphin social systems
and their response to human-induced changes in the marine environment.