The evolution of intergroup conflict in animal societies

Intergroup conflict has been proposed as one of the major forces promoting the evolution of cooperation in animal societies ranging from termites to humans. In principle intergroup conflict could play a broader role in major transitions in social organisation, uniting the fitness interests of ‘unlike’ units and driving groups toward new tiers of biological complexity. Here I discuss research which sheds light on the evolution of war and peace in animal societies and the potential role of intergroup conflict in social evolution.