Intergroup conflict is a major evolutionary force sha** animal and human societies. Males
and females should, on average, experience different costs and benefits for participating in …

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 …

Intergroup violence is challenging to understand: why do individuals cooperate to harm
members of other groups when they themselves may be killed or injured? Despite progress …

Neighbouring groups compete over access to resources and territories in between-group
encounters, which can escalate into between-group conflicts (BGCs). Both the ecological …

Female mammals employ reproductive strategies (eg, internal gestation) that result in power
asymmetries specific to intersexual dyads. Because the number of eggs available for …

Conflicts between social groups or “intergroup contests” are proposed to play a major role in
the evolution of cooperation and social organization in humans and some nonhuman animal …

In group-living species, cooperative tactics can offset asymmetries in resource-holding
potential between individuals and alter the outcome of intragroup conflicts. Differences in the …

The costs and benefits of group living are also reflected in intraspecific variation in group
size. Yet, little is known about general patterns of fitness consequences of this variation. We …

In group-living animals, between-group relations are often revealed during intergroup
encounters, which may be intolerant (competitive), affiliative (cooperative) or neutral. We …

Intergroup relationships vary greatly among primate species from peaceful intermingling in
some species, to the consistent defense of territorial borders in others, to ritualized signaling …