The Reseach Institute For Humanity & Nature

In the field of forensic sciences, human teeth are used to identify individuals in cases involving unidentified bodies. In recent years, isotope analysis of tooth enamel has been increasingly employed to estimate birth year and place of birth. The enamel is formed between the prenatal period and childhood, and after the tooth crown is complete, it does not undergo additional growth. Therefore, the oxygen isotope composition of the enamel bioapatite is significantly influenced by the environmental conditions during these periods, including dietary habits and tap water consumption. In this study, we aimed to predict the places of birth of 65 Japanese individuals, whose places of birth were known, by analysing the oxygen isotope ratios in carbonates in the enamel bioapatite. The oxygen isotope ratio in bioapatite varied from a maximum value of −3.4‰ to a minimum of −8.76‰, indicating lower and higher values in cold and warm areas, respectively. Furthermore, a correlation was observed between the oxygen isotope ratios and the latitudes and average annual temperatures of the place of residence during enamel formation (correlation coefficients: −0.84 and 0.81, respectively). Oxygen isotope analysis of enamel bioapatite can help in determining the environmental conditions in the place of residence during enamel formation. Overall, oxygen isotope analysis can be useful in predicting the place of residence during enamel formation of individuals in Japan.Key Points  Oxygen isotope ratios in tooth enamel bioapatite were analysed to determine the birthplaces of Japanese individuals.The oxygen isotope ratio correlated with the latitude and average annual temperature of the place of residence during enamel formation.Oxygen isotope analysis can help in estimating the place of birth of individuals in Japan.

Through primatology, I realized it was possible to examine sociality from a perspective outside of the human species. I joined Kyoto University's Laboratory of Physical Anthropology under the supervision of Imanishi Kinji and Itani Junichiro. I decided to pursue field-based discovery research on Japanese macaques and gorillas aligned with my mentor's frameworks. First, I traversed Japan, investigating macaque ecology, sociality, and morphologic variation. Next, Iinvestigated the socio-ecology of gorillas in Africa. I focused on Grauer's gorillas in Kahuzi-Biega National Park (Zaire), and mountain gorillas in Volcanoes National Park (Rwanda). These populations exhibited differences in the prevalence of multi-male groups, female migration patterns, and male group formations. Under the supervision of Dian Fossey in Rwanda, I studied male and group life histories. Following Fossey's tragic death and The movement of Karisoke Research Centre outside the park. I resolved to collaborate with local researchers and engage in community conservation activities. In Kahuzi, I studied the sympatric coexistence of gorillas and chimpanzees in higher and lower regions. They share habitats and diets but adopt different foraging strategies, particularly during periods of fruit scarcity. Early humans adopted a strategy of "turning weaknesses into strengths."This approach enabled us to colonize diverse environments inaccessible to other primates. Modern society has shifted toward a strategy of "amplifying strengths" through technology, leading to significant degradation of the environment. Field studies of nonhuman primates can shed light on the nature and origins of human societies. Continuation of field research is crucial for envisioning and shaping a prosperous future for humanity.