Why war is a man's game

Alberto Jacopo Cesare Micheletti, Graeme Douglas Ruxton, Andy Gardner

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Interest in the evolutionary origins and drivers of warfare in ancient and contemporary small-scale human societies has greatly increased in the last decade, and has been particularly spurred by exciting archaeological discoveries that suggest our ancestors led more violent lives than previously documented. However, the striking observation that warfare is an almost-exclusively male activity remains unexplained. Three general hypotheses have been proposed, concerning greater male effectiveness in warfare, lower male costs, and patrilocality. But while each of these factors might explain why warfare is more common in men, they do not convincingly explain why women almost never participate. Here, we develop a mathematical model to formally assess these hypotheses. Surprisingly, we find that exclusively male warfare may evolve even in the absence of any such sex differences, though sex biases in these parameters can make this evolutionary outcome more likely. The qualitative observation that participation in warfare is almost exclusive to one sex is ultimately explained by the fundamentally sex-specific nature of Darwinian competition—in fitness terms, men compete with men and women with women. These results reveal a potentially key role for ancestral conditions in shaping our species' patterns of sexual division of labour and violence-related adaptations and behavioural disorders.
Original languageEnglish
Article number20180975
Number of pages8
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1884
Publication statusPublished - 15 Aug 2018


  • War
  • Violence
  • Sex differences
  • Competition
  • Hysteresis
  • Behavioural disorders


Dive into the research topics of 'Why war is a man's game'. Together they form a unique fingerprint.

Cite this