In this paper, we consider three hypotheses to account for the evolution of the extraordinary
capacity for large-scale cooperation and altruistic social preferences within human societies …

Out-group conflict is rife in the natural world, occurring from primates to ants. Traditionally,
research on this aspect of sociality has focused on the interactions between groups and their …

Evolutionary anthropologists seek to understand the evolution of warfare across multiple
timescales, from the roots of warfare in the intergroup aggression of our primate ancestors …

Free-ranging adult male baboons give loud two-syllable 'wahoo'calls during dawn choruses,
interactions between groups, when chasing females, and in aggressive interactions with …

How can collective action evolve when individuals benefit from cooperation regardless of
whether they pay its participation costs? According to one influential perspective, collective …

We present results of a 10-year study of free-ranging gray-footed chacma baboons (Papio
ursinus griseipes) in the Okavango Delta of Botswana. The majority of deaths among adult …

Group members do not always act cohesively when facing extra-group rivals. When benefits
such as group-defence are not monopolizable, it poses an economics problem: who should …

Male chimpanzees, Pan troglodytes, defend group territories, and sometimes injure or kill
members of other groups. To test which factors best predict the occurrence and outcomes of …

Numerical superiority confers a competitive advantage during contests among animal
groups, shaping patterns of resource access, and, by extension, fitness. However, relative …

In social-living animals, interactions between groups are frequently agonistic, but they can
also be tolerant and even cooperative. Intergroup tolerance and cooperation are regarded …