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.

在这篇文章中，我总结了我的研究生涯，参考了京都大学体质人类学实验室 (LPA) 早期由今西欣司和板谷纯一郎领导的时期。当我在 1975 年开始研究日本猕猴的性行为时，我有一些意想不到的观察结果。高级男性没有获得高交配成功率。发情的雌性通常会拒绝地位高的雄性的求爱，而选择与地位低的雄性交配。一些男女配对表现出持久的亲密关系，但他们避免交配。女性经常表现出“过度”的性行为。对其中一些观察结果的明确解释并不存在。之后，我多次更换研究对象，从黑猩猩、屋久岛猕猴（日本猕猴的亚种）到环尾狐猴。很难将我的发现总结成一个前后一致的故事。相反，我回顾了我的研究和经历。在我的整个职业生涯中，我牢记两件事。第一个是由今西在京都大学体质人类学实验室建立的：探索人类社会的进化。其次，我试图用进化论来理解看似不可理解的现象。尽管坚持这些基本概念，但事情并不总是按计划进行。我试图用进化论来理解看似不可理解的现象。尽管坚持这些基本概念，但事情并不总是按计划进行。我试图用进化论来理解看似不可理解的现象。尽管坚持这些基本概念，但事情并不总是按计划进行。