, Volume 24, Issue 2, pp 211–221 | Cite as

Party size and early detection of predators in sumatran forest primates

  • Carel P. van Schaik
  • Maria A. van Noordwijk
  • Bambang Warsono
  • Edy Sutriono


Theoretical considerations suggest that the ability to detect the presence or approach of a predator when there is still enough time to flee (early detection) should improve with group size, if group living is to be advantageous for individual non-human primates. The hypothesis that the distance at which forest primates detect predators increases with the size of their party was confirmed by observation. It was found that in addition to party size height (vegetation density) could also influence detection distance. Because height relates not only to visibility but also to the number of potential predators, one would predict that small parties are found higher in the canopy to compensate for the increased risk of predation. This prediction was confirmed using data on long-tailed macaques (Macaca fascicularis).

The correlation found between party size and predation risk demonstrates that forest monkeys can adjust their behaviour in response to changes in predation risk, and hence support the hypothesis that predation risk has been an important, perhaps even the only, selective force responsible for the evolution of group living in non-human primates.


Early Detection Group Size Predation Risk Theoretical Consideration Animal Ecology 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Alexander, R. D., 1974. The evolution of social behavior.Ann. Rev. Ecol. Syst., 5: 325–383.CrossRefGoogle Scholar
  2. Altmann, S. A. &J. Altmann, 1970.Baboon Ecology. Chicago Univ. Press, Chicago.Google Scholar
  3. Bartles, M., 1929. Iets over het voedsel van de panter.De Tropische Natuur, 18: 81–83.Google Scholar
  4. Bertram, B. C. R., 1978. Living in groups: predators and prey. In:Behavioural Ecology,J. R. Krebs &N. B. Davies (eds.), Blackwell, Oxford, pp. 64–96.Google Scholar
  5. Clutton-Brock, T. H. &P. H. Harvey, 1977. Primate ecology and social organization.J. Zool. (London), 183: 1–39.Google Scholar
  6. Hamilton, W. D., 1971. Geometry and the selfish herd.J. Theor. Biol., 31: 295–311.CrossRefPubMedGoogle Scholar
  7. Hoogland, J. L., 1981. The evolution of coloniality in white-tailed and black-tailed prairie dogs (Sciuridae:Cynomys leucurus andC. ludovicianus).Ecology, 62: 252–272.Google Scholar
  8. ———— &P. W. Sherman, 1976. Advantages and disadvantages of bank swallow (Riparia riparia) coloniality.Ecol. Monogr., 46: 33–58.Google Scholar
  9. Jorde, L. B. &J. N. Spuhler, 1974. A statistical analysis of selected aspects of primate demography, ecology and social behaviour,J. Anthropol. Res., 30: 199–224.Google Scholar
  10. Marler, P., 1955. Characteristics of some animal calls.Nature, 176: 6–8.Google Scholar
  11. Pulliam, H. R., 1973. On the advantages of flocking.J. Theor. Biol., 38: 419–422.CrossRefPubMedGoogle Scholar
  12. Raemaekers, J. J. &D. J. Chivers, 1980. Socio-ecology of forest primates. In:Malayan Forest Primates,D. J. Chivers (ed.), Plenum Press, New York, pp. 279–316.Google Scholar
  13. Rijksen, H. D., 1978.A Field Study on Sumatran Orang Utans (Pongo pygmaeus abelliLesson 1827):Ecology, Behaviour and Conservation. Veenman, Wageningen.Google Scholar
  14. Rowell, T. E. &S. M. Richards, 1979. Reproductive strategies of some African monkeys.J. Mammal., 60: 58–69.Google Scholar
  15. Schaik, C. P. van, M. A. van Noordwijk, R. J. de Boer & I. den Tonkelaar, in press. The effect of group size on time budgets and social behaviour in wild long-tailed macaques (Macaca fascicularis).Behav. Ecol. Sociobiol.Google Scholar
  16. Schaller, G. B., 1967.The Deer and the Tiger. Chicago Univ. Press, Chicago.Google Scholar
  17. Siegel, S., 1956.Nonparametric Statistics for the Behavioral Sciences. McGraw-Hill, New York.Google Scholar
  18. Sokal, R. R. &F. J. Rohlf, 1969.Biometry. Freeman, San Francisco.Google Scholar
  19. Treisman, M., 1975. Predation and the evolution of gregariousness. I. Models for concealment and evasion.Anim. Behav., 23: 779–800.Google Scholar
  20. Vine, I., 1971. Risk of visual detection and pursuit by a predator and the selective advantage of flocking behaviour.J. Theor. Biol., 30: 405–422.CrossRefPubMedGoogle Scholar
  21. Waser, P. M., 1977. Feeding, ranging and group size in the mangabey,Cercocebus albigena. In:Primate Ecology,T. H. Clutton-Brock (ed.), Academic Press, London, pp. 183–222.Google Scholar
  22. Whitten, A. J., 1980. The kloss gibbon in Siberut rain forest. Ph.D. thesis, Univ. of Cambridge.Google Scholar
  23. Wrangham, R. W., 1980. An ecological model of female-bonded primate groups.Behaviour, 75: 262–300.Google Scholar

Copyright information

© Japan Monkey Centre 1983

Authors and Affiliations

  • Carel P. van Schaik
    • 1
  • Maria A. van Noordwijk
    • 1
  • Bambang Warsono
    • 2
  • Edy Sutriono
    • 2
  1. 1.Laboratorium voor Vergelijkende FysiologieRijksuniversiteit UtrechtUtrechtThe Netherlands
  2. 2.Fakultas BiologiUniversitas Nasional, Jl. Kebun Binatang RagunanJakarta SelatanIndonesia

Personalised recommendations