Correlates of individual participation in boundary patrols by male chimpanzees

Anthony Massaro, Ian Gilby, Nisarg Desai, ALEXANDER Weiss, Joseph Feldblum, Anne Pusey, Michael Wilson

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Group territory defense poses a collective action problem: individuals can free-ride, benefiting without paying the costs. Individual heterogeneity has been proposed to solve such problems, as individuals high in reproductive success, rank, fighting ability, or motivation may benefit from defending territories even if others free-ride. To test this hypothesis, we analyzed years of data from chimpanzees (Pan troglodytes) in the Kasekela community, Gombe National Park,
Tanzania (1978-2007). We examined the extent to which individual participation in patrols varied according to correlates of reproductive success (mating rate, rank, age), fighting ability (hunting), motivation (scores from personality ratings), costs of defecting (the number of adult males in the community), and gregariousness (sighting frequency). In contrast to expectations from collective action theory, males participated in patrols at consistently high rates (mean ±
S.D. = 74.5 ± 11.1% of patrols, n=23 males). The best predictors of patrol participation were sighting frequency, age, and hunting participation. Current and former alpha males did not participate at a higher rate than males that never achieved alpha status. These findings suggest that the temptation to free-ride is low, and that a mutualistic mechanism such as group augmentation may better explain individual participation in group territorial behavior.
Original languageEnglish
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Issue number1851
Early online date4 Apr 2022
Publication statusPublished - 23 May 2022

Keywords / Materials (for Non-textual outputs)

  • collection action problems
  • Pan troglodytes
  • territorial behaviour
  • intergroup aggression
  • hunting
  • boundary patrols


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