My studies of primates: Sex, affinity, and competition

Primates. 2023 May;64(3):285-303. doi: 10.1007/s10329-023-01063-y. Epub 2023 Apr 4.

Abstract

In this essay, I summarize my research career, with reference to the early days of the Laboratory of Physical Anthropology (LPA) at Kyoto University led by Kinji Imanishi and Junichiro Itani. When I started conducting research on the sexual behavior of Japanese macaques in 1975, I made some unexpected observations. High-ranking males did not obtain high mating success. Estrous females often rejected the courtships of high-ranking males and chose to mate with lower-ranking males. Some male-female dyads exhibited long-lasting affinitive relations, but they avoided mating. Females frequently showed 'excessive' sexuality. Clear explanations for some of these observations do not exist. After that, I changed my study subjects several times from chimpanzees, Yakushima macaques (a subspecies of Japanese macaque), and ringtailed lemurs. It is difficult to summarize my findings into a consistent story. Instead, I review my research and experiences. Throughout my career, I kept two things in mind. The first was established by Imanishi at the Laboratory of Physical Anthropology at Kyoto University: to explore the evolution of human society. Second, I tried to understand seemingly incomprehensible phenomena using evolutionary theory. Despite adhering to these foundational concepts, things did not always work out as planned.

Keywords: Chimpanzee; Japanese macaque; Reproduction; Ringtailed lemur; Sexual behavior; Social relationships.

Publication types

  • Review

MeSH terms

  • Animals
  • Courtship
  • Estrus
  • Female
  • Humans
  • Lemur*
  • Macaca
  • Macaca fuscata
  • Male
  • Sexual Behavior, Animal*