Homophily around specialized foraging underlies dolphin social preferences

Area of Science:

• Behavioral Ecology
• Animal Social Networks
• Marine Mammal Behavior

Background:

• Social structure in animal populations is often influenced by individual associations.
• Homophily, the principle that individuals associate with similar others, is a proposed driver of social clustering.
• Bottlenose dolphin populations exhibit apparent social clustering around specialized foraging tactics, necessitating investigation into underlying social drivers.

Purpose of the Study:

• To test the hypothesis of homophily in a bottlenose dolphin population.
• To determine the influence of sex, age, genetic relatedness, home range, and foraging tactics on social associations.
• To assess whether homophily extends beyond specific foraging behaviors.

Main Methods:

• Social network analysis was applied to a bottlenose dolphin population.
• Individual attributes including sex, age, genetic relatedness, home range, and foraging tactic frequency were measured.
• Statistical models controlled for non-homophilous factors to isolate the effects of behavioral and spatial similarity on social associations.

Main Results:

• Dolphins showed significant social clustering based on similar home ranges.
• Association patterns were also influenced by the frequency of using a specialized cooperative foraging tactic.
• Homophilous social preferences were evident even when dolphins were not actively foraging, indicating broader social affiliations.

Conclusions:

• Homophily based on shared home range and specialized foraging tactics significantly structures bottlenose dolphin social groups.
• Social preferences are not solely driven by kinship or age, and extend beyond immediate foraging activities.
• Homophily around behavioral specialization may be a widespread driver of social patterns in animal populations, impacting social learning and cultural transmission.