Sequence of quorums during collective decision making in macaques
- 231 Downloads
Synchronization of activity is one of the major challenges of any society, and to what extent social animals reach a consensus still remains to be established. In the case of group movements, recent studies have underlined the importance of the pre-departure period and suggested that some individuals in a group express their motivation to move by showing a preference for a specific direction. However, how do other group members really choose the time and direction of movement? This study shows that in two semi-free ranging Tonkean macaque (Macaca tonkeana) groups, several individuals propose different directions for movement by displaying unique behavior. The whole group eventually moves in the choice of direction supported by the majority of individuals according to a sequence of three quorum rules. Moreover, when the number of individuals choosing another direction is higher than their own group, individuals that proposed alternative directions eventually renounce and follow the majority. Despite conflict of interests, group members reach a consensus before the actual start of group movement. This demonstrates that processes of this type, which can be considered to be voting processes, are not exclusive to human societies and may be explained by a complex sequence of simple rules.
KeywordsConsensus Voting process Vote Threshold Primates Group movement Self-organization
The authors are grateful to M. Pelé and J. Dubosq for the video analyses. We thank N. Poulin for statistical advice as well as L. Conradt, E. Danchin and R. Bon for helpful comments on this manuscript. This work was supported by the European Doctoral College of Strasbourg Universities, the French Research Ministry, the French Foreign Ministry, the Franco-American Commission, the Fyssen Foundation, and the Belgian National Funds for Scientific Research.
- Byrne R, Whiten A (1988) Machiavellian intelligence: social expertise and the evolution of intellect in monkeys, apes and humans. Oxford University Press, OxfordGoogle Scholar
- Cox DR, Oakes D (1984) Analysis of survival data. London, UK: Chapman and HallGoogle Scholar
- Kummer H (1968) Social organization of hamadryas baboons. University of Chicago Press, ChicagoGoogle Scholar
- Meunier H, Leca JB, Deneubourg JL, Petit O (2006) Group movement decisions in capuchin monkeys: the utility of an experimental study and a mathematical model to explore the relationship between individual and collective behaviours. Behaviour 143:1511–1527. doi: 10.1163/156853906779366982 CrossRefGoogle Scholar
- Norton GW (1986) Leadership decision processes of group movement in yellow baboons. In: Else JG, Lee PC PC (eds) Primate ecology and conservation. Cambridge University Press, Cambridge, pp 145–156Google Scholar
- Prins HHT (1996) Ecology and behaviour of the African buffalo. Chapman & Hall, LondonGoogle Scholar
- Supriatna J, Froehlich JW, Erwin JM, Southwick CH (1992) Population habitat and conservation status of M. maurus, M. tonkeana and their putative hybrids. Trop Biodivers 1:31–48Google Scholar
- Tomasello M, Call J (1997) Primate cognition. Oxford University Press, New York, 517 ppGoogle Scholar
- Whitten AJ, Mustafa M, Henderson GS (1987) The ecology of sulawesi. Gadjah Mada University Press, Yogyakarta, p 777Google Scholar