Cooperation-based concept formation in male bottlenose dolphins

Area of Science:

• Animal behavior
• Cognitive ethology
• Marine mammal science

Background:

• Male bottlenose dolphins in Shark Bay, Western Australia, exhibit complex nested alliances for female herding and defense.
• These alliances operate at multiple hierarchical levels (first, second, and third-order).
• The cognitive mechanisms underlying how dolphins classify these nested relationships were previously unknown.

Purpose of the Study:

• To investigate how male bottlenose dolphins classify their complex, nested social alliances.
• To determine if dolphins possess a social concept of cooperative team membership.

Main Methods:

• Utilized 30 years of behavioral data from Shark Bay dolphin populations.
• Conducted 40 contemporary sound playback experiments targeting allied male dolphins.
• Recorded male responses using drone-mounted video and a hydrophone array.

Main Results:

• Males demonstrated a first-person social concept of cooperative team membership specifically at the second-order alliance level.
• This classification was independent of first-order alliance history.
• The concept was also independent of current relationship strength across all three alliance levels.

Conclusions:

• Male bottlenose dolphins form associative concepts of cooperative team membership, indicating advanced social cognition.
• These cooperation-based concepts are not unique to humans and occur in societies with extensive non-kin cooperation.
• The findings suggest that such concepts may have played a role in the evolution of cooperation in early humans.