We documented nine male homosexual consortships within three different male–male dyads in a free-ranging all-male group of Japanese macaques (Macaca fuscata), at Minoo, Japan. A total of 63 male–male mounts were observed during these consortships. Male homosexual interactions shared most of the behavioral components that have been reported to characterize heterosexual and female homosexual consortships in this species. Convergent behavioral data, including analysis of male–male solicitations, mounting postures, body orientations, inter-mount activities, and third-party male intrusions supported the conclusion that male–male consortships are a sexual phenomenon. We discussed a series of proximate and ultimate hypotheses that purport to account for the occurrence of male homosexual behavior in all-male groups of primates, including humans. This first report of male homosexual interactions in an all-male group of Japanese macaques contributes to the growing database used to provide insights into the developmental processes, causal mechanisms, adaptive significance, and phylogenetic pathways of same-sex sexual behavior.
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Isosexual behavior includes same-sex mounting and presentation and is considered a neutral term (rather than sociosexual, homosexual, or bisexual behavior) that does not involve any assumptions about the motivation of the participants (Dixson, 2012).
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This study was funded by the following agencies: Natural Sciences and Engineering Research Council of Canada (NSERC), Alberta Innovates Health Solutions (AIHS), Japan Society for the Promotion of Science (JSPS), American Institute of Bisexuality (AIB), the L.S.B. Leakey Foundation, as well as the Office of the Dean of Arts and Science and the Office of Research Services at the University of Lethbridge. We thank Lydia Ottenheimer Carrier for assistance with data collection. We thank Penny D’Agnone for help securing AIHS funding. We thank Y. Iwanaga for permission to work at Meiji Memorial Forest Minoo Park and S. Suzuki for valuable information in the field. We thank the Editor, Alan Dixson, and one anonymous reviewer for fruitful comments on a previous version of the article.
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Leca, JB., Gunst, N. & Vasey, P.L. Male Homosexual Behavior in a Free-Ranging All-Male Group of Japanese Macaques at Minoo, Japan. Arch Sex Behav 43, 853–861 (2014). https://doi.org/10.1007/s10508-014-0310-6
- Male–male consortship
- Ventro-ventral mounts
- Sociosexual behavior
- Macaca fuscata