Citation

Lehmann L, Feldman MW. Proc. Biol. Sci. 2008; 275(1653): 2877-2885.

Affiliation

Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. lehmann@stanford.edu

Copyright

(Copyright © 2008, Royal Society of London)

DOI

10.1098/rspb.2008.0842

PMID

18755675

PMCID

PMC2605837

Abstract

Tribal war occurs when a coalition of individuals use force to seize reproduction-enhancing resources, and it may have affected human evolution. Here, we develop a population-genetic model for the coevolution of costly male belligerence and bravery when war occurs between groups of individuals in a spatially subdivided population. Belligerence is assumed to increase an actor's group probability of trying to conquer another group. An actor's bravery is assumed to increase his group's ability to conquer an attacked group. We show that the selective pressure on these two traits can be substantial even in groups of large size, and that they may be driven by two independent reproduction-enhancing resources: additional mates for males and additional territory (or material resources) for females. This has consequences for our understanding of the evolution of intertribal interactions, as hunter-gatherer societies are well known to have frequently raided neighbouring groups from whom they appropriated territory, goods and women.

Language: en