International Journal of Primatology

, Volume 25, Issue 5, pp 1033–1041

Male Masturbation in Free-Ranging Japanese Macaques

  • Ruth Thomsen
  • Joseph Soltis


We studied masturbatory behavior of males over a 14-mo period in free-ranging Japanese macaques (Macaca fuscata yakui) on Yakushima island, Japan. We distinguished 2 types: (1) masturbation only and (2) masturbation with final ejaculation. Both types occurred in all 15 adult troop males. We calculated masturbation only as an index (M/h). It occurred over the whole year; however, it was more frequent during the mating than during the non-mating periods. Masturbation with ejaculation was restricted to the mating period. Male mating success correlated positively with social status. Both rate of masturbation only and masturbatory ejaculations increased as male social status and male mating success declined. Lower-ranking males had higher rates of masturbation only, i.e., they spent more time masturbating than higher-ranking males did. Lower-ranking males also had higher proportions of ejaculates for masturbation, while higher-ranking males used most of their ejaculates for mating.

masturbation Japanese macaques Yakushima 


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Copyright information

© Springer Science+Business Media, Inc. 2004

Authors and Affiliations

  • Ruth Thomsen
    • 1
  • Joseph Soltis
    • 2
  1. 1.Department of Evolutionary EcologyInstitute for Zoo and Wildlife ResearchBerlinGermany
  2. 2.Animal Programs Administration, Disney's Animal Kingdom, P.O. BoxWildlife Tracking CenterLake Buena VistaUSA

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