AbstractThe authors explore coalitional play fighting (in which teams of at least two play against each other to achieve a goal) across hunter-gatherer societies, with the theory that play of this type may be a mechanism for assessing strength and utility for future defense or warfare. When played against other communities, they propose coalitional play fighting can also serve to gauge strength of potential allies or formidability of potential enemies. In order to test their theories, they predict that, despite the large energy cost and risk of sports associated with coalitional play fighting, these types of games will be widespread in hunter-gatherer societies. In addition, they predict that of those exhibiting coalitional play fighting, many will play against other communities. In support of their hypotheses, they find that 54% of hunter-gatherer societies examined exhibit coalitional play fighting, of which 81% play against other communities.