Abstract
Recent experiments have demonstrated the importance of numerical assessment in animal contests. Nevertheless, few attempts have been made to model explicitly the relationship between the relative number of combatants on each side and the costs and benefits of entering a contest. One framework that may be especially suitable for making such explicit predictions is Lanchester's theory of combat, which has proved useful for understanding combat strategies in humans and several species of ants. We show, with data from a recent series of playback experiments, that a model derived from Lanchester's 'square law' predicts willingness to enter intergroup contests in wild chimpanzees (Pan troglodytes). Furthermore, the model predicts that, in contests with multiple individuals on each side, chimpanzees in this population should be willing to enter a contest only if they outnumber the opposing side by a factor of 1.5. We evaluate these results for intergroup encounters in chimpanzees and also discuss potential applications of Lanchester's square and linear laws for understanding combat strategies in other species.
Full Text
The Full Text of this article is available as a PDF (91.4 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Heinsohn R. Group territoriality in two populations of African lions. Anim Behav. 1997 Jun;53(6):1143–1147. doi: 10.1006/anbe.1996.0316. [DOI] [PubMed] [Google Scholar]
- West S. A., Murray M. G., Machado C. A., Griffin A. S., Herre E. A. Testing Hamilton's rule with competition between relatives. Nature. 2001 Jan 25;409(6819):510–513. doi: 10.1038/35054057. [DOI] [PubMed] [Google Scholar]
- Wrangham R. W. Evolution of coalitionary killing. Am J Phys Anthropol. 1999;Suppl 29:1–30. doi: 10.1002/(sici)1096-8644(1999)110:29+<1::aid-ajpa2>3.3.co;2-5. [DOI] [PubMed] [Google Scholar]