Behavioral Ecology and Sociobiology

, Volume 60, Issue 5, pp 695–706

Comparative tests of reproductive skew in male primates: the roles of demographic factors and incomplete control

Original Article


Reproductive skew models have been proposed as a unifying framework for understanding animal social systems, but few studies have investigated reproductive skew in a broad evolutionary context. We compiled data on the distribution of mating among males for 31 species of primates and calculated skew indices for each study. We analyzed the determinants of mating skew with phylogenetic comparative methods to investigate two models from reproductive skew theory, the concession model and the tug-of-war model. Mating skew decreased as the number of males increased in multimale groups, suggesting that monopolization of females becomes more difficult when there are more rivals, and therefore supporting the tug-of-war model. We predicted that single males are unable to monopolize receptive females as overlap in female receptivity increases (estrous synchrony) and, as a result, that mating skew decreases. However, we did not find any evidence for a link between female estrous synchrony and male mating skew. Finally, the concession model predicts high skew in male philopatric species relative to species in which males disperse, yet our measures of mating skew showed no significant associations with qualitative scores of male dispersal. More definitive tests of the concession model will require more quantitative measures of relatedness, which are presently unavailable for most primate species in our study. Overall, our results provide support for the tug-of-war model in primates, and the approach developed here can be applied to study comparative patterns of skew in other biological systems.


Reproductive skew Primates Tug-of-war model Estrous synchrony Phylogenetic comparative test 

Supplementary material

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of Biological Sciences, Graduate School of SciencesUniversity of TokyoTokyoJapan
  2. 2.Max Planck Institute for Evolutionary AnthropologyLeipzigGermany
  3. 3.Department of Integrative BiologyUniversity of CaliforniaBerkeleyUSA
  4. 4.Laboratory for BiolinguisticsRIKEN Brain Science InstituteTokyoJapan

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