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Interspecies sexual behaviour between a male Japanese macaque and female sika deer


Interspecies sexual behaviour or ‘reproductive interference’ has been reported across a wide range of animal taxa. However, most of these occurrences were observed in phylogenetically close species and were mainly discussed in terms of their effect on fitness, hybridization and species survival. The few cases of heterospecific mating in distant species occurred between animals that were bred and maintained in captivity. Only one scientific study has reported this phenomenon, describing sexual harassment of king penguins by an Antarctic fur seal. This is the first article to report mating behaviour between a male Japanese macaque (Macaca fuscata yakui) and female sika deer (Cervus nippon yakushimae) on Yakushima Island, Japan. Although Japanese macaques are known to ride deer, this individual showed clearly sexual behaviour towards several female deer, some of which tried to escape whilst others accepted the mount. This male seems to belong to a group of peripheral males. Although this phenomenon may be explained as copulation learning, this is highly unlikely. The most realistic hypothesis would be that of mate deprivation, which states that males with limited access to females are more likely to display this behaviour. Whatever the cause for this event may be, the observation of highly unusual animal behaviour may be a key to understanding the evolution of heterospecific mating behaviour in the animal kingdom.

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  • Anne O, Rasa E (1983) Dwarf mongoose and hornbill mutualism in the Taru desert, Kenya. Behav Ecol Sociobiol 12:181–190

    Article  Google Scholar 

  • Axelrod R, Hamilton W (1981) The evolution of cooperation. Science 211:1390–1396

    CAS  Article  PubMed  Google Scholar 

  • Beetz AM (2004) Bestiality/zoophilia: a scarcely investigated phenomenon between crime, paraphilia, and love. J Forensic Psychol Pract 4:1–36

    Article  Google Scholar 

  • Beirne P (2009) Confronting animal abuse: law, criminology, and human-animal relationships. Rowman & Littlefield Publishers, New York

    Google Scholar 

  • Burdfield-Steel ER (2012) The causes and consequences of reproductive interference in the Lygaeidae. Doctoral dissertation, University of St Andrews

  • Clutton-Brock T (2002) Breeding together: kin selection and mutualism in cooperative vertebrates. Science 296:69–72

    CAS  Article  PubMed  Google Scholar 

  • Clutton-Brock TH, Parker GA (1995) Sexual coercion in animal societies. Anim Behav 49:1345–1365

    Article  Google Scholar 

  • de Bruyn PN, Tosh CA, Bester MN (2008) Sexual harassment of a king penguin by an Antarctic fur seal. J Ethol 26:295–297

    Article  Google Scholar 

  • Freedman H, Waltman P (1984) Persistence in models of three interacting predator-prey populations. Math Biosci 68:213–231

    Article  Google Scholar 

  • Gröning J, Hochkirch A (2008) Reproductive interference between animal species. Q Rev Biol 83:257–282

    Article  PubMed  Google Scholar 

  • Gunst N, Leca J, Vasey PL (2015) Influence of sexual competition and social context on homosexual behavior in adolescent female Japanese macaques. Am J Primatol 77:502–515

    Article  PubMed  Google Scholar 

  • Haddad WA, Reisinger RR, Scott T et al (2015) Multiple occurrences of king penguin (Aptenodytes patagonicus) sexual harassment by Antarctic fur seals (Arctocephalus gazella). Polar Biol 38:741–746

    Article  Google Scholar 

  • Herzing DL, Elliser CR (2013) Directionality of sexual activities during mixed-species encounters between Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus). Int J Comp Psychol 26(2):124–134

    Google Scholar 

  • Jędrzejewski W, Jędrzejewska B, Okarma H, Ruprecht AL (1992) Wolf predation and snow cover as mortality factors in the ungulate community of the Bialowieża National Park, Poland. Oecologia 90:27–36

    Article  PubMed  Google Scholar 

  • Kyogoku D (2015) Reproductive interference: ecological and evolutionary consequences of interspecific promiscuity. Popul Ecol 57:253–260

    Article  Google Scholar 

  • Matsubara M (2003) Costs of mate guarding and opportunistic mating among wild male Japanese macaques. Int J Primatol 24:1057–1075

    Article  Google Scholar 

  • Nishikawa M, Mochida K (2010) Coprophagy-related interspecific nocturnal interactions between Japanese macaques (Macaca fuscata yakui) and sika deer (Cervus nippon yakushimae). Primates 51:95–99

    Article  PubMed  Google Scholar 

  • Pays O, Ekori A, Fritz H (2014) On the advantages of mixed-species groups: impalas adjust their vigilance when associated with larger prey herbivores. Ethology, n/a-n/a. doi:10.1111/eth.12292

    Google Scholar 

  • Prasad TR, Rao R, Sanjay M, Sharma R (2013) Grooming of sambar (Rusa unicolor) by rhesus macaque (Macaca mulatta) in Sariska Tiger Reserve, Rajasthan. India. Curr Sci 104(3):296–298

    Google Scholar 

  • Shimada M (2009) The “difficulties” and “interest” of study of play: a genealogy of ethology. In: Kamei N (ed) Introduction to anthropology of play. Showado, Kyoto, pp 21–37 (in Japanese)

  • Shuker DM, Currie N, Hoole T, Burdfield-Steel ER (2015) The extent and costs of reproductive interference among four species of true bug. Popul Ecol 57:321–331

    Article  Google Scholar 

  • Sprague DS (1991) Mating by nontroop males among the Japanese macaques of Yakushima Island. Folia Primatol (Basel) 57:156–158

    Article  Google Scholar 

  • Takahata Y, Suzuki S, Agetsuma N et al (1998) Reproduction of wild Japanese macaque females of Yakushima and Kinkazan Islands: a preliminary report. Primates 39:339–349

    Article  Google Scholar 

  • Thomsen R, Soltis J (2004) Male masturbation in free-ranging Japanese macaques. Int J Primatol 25:1033–1041

    Article  Google Scholar 

  • Tsuji Y, Shimoda-Ishiguro M, Ohnishi N, Takatsuki S (2007) A friend in need is a friend indeed: feeding association between Japanese macaques and sika deer. Acta Theriol (Warsz) 52:427–434

    Article  Google Scholar 

  • Yamagiwa J, Izawa K, Maruhashi T (1998) Long-term studies on wild Japanese macaques in natural habitats at Kinkazan and Yakushima: preface. Primates 39:255–256

    Article  Google Scholar 

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This article and this observation were made possible by funds donated to the “Saru: Singes du Japon” Grant Initiative d’Excellence W15RJSHO project by the University of Strasbourg and the French Ministry for Higher Education. We also thank Hiroyuki Miyamoto from JSPS Strasbourg office and Hideki Sugiura from Kyoto University Wildlife Research Center for their help on Yakushima Island. We thank Munro Language Services for English language editing.

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Correspondence to Cédric Sueur.

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Authors declare no competing interests and no conflicts of interests. Our approach solely involved observations of non-human animals. Animals were not handled, and no invasive experiments were carried out. This study was conducted with the approval of the Prefecture of Kagoshima (with the help of the Wildlife Research Centre and the Japanese Society for the Promotion of Science) to be in the Yakushima Forest and with the authorisation of our institute (IPHC, CNRS). Animals were already used to human presence on Yakushima.

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Supplementary video file: Movie of sexual mounts of a Japanese macaque male on two different deer: (MP4 87498 kb)

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Pelé, M., Bonnefoy, A., Shimada, M. et al. Interspecies sexual behaviour between a male Japanese macaque and female sika deer. Primates 58, 275–278 (2017).

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  • Heterospecific mating
  • Sexual harassment
  • Primate
  • Macaca fuscata yakui
  • Reproductive interference