We studied the island-wide distribution of wild Japanese macaques in Yakushima (Macaca fuscata yakui) in May 2017 and 2018. We walked 165.4 km along roads and recorded the location of 842 macaque feces. We divided the roads into segments 50 m in length (N=3308) and analyzed the effect of the areas of farms and villages or conifer plantations around the segments and also the presence of hunting for pest control on the presence or absence of feces. We divided the island into three areas based on population trend changes over the past two decades: north and east (hunting present, population decreasing); south (hunting present, no change) and west (hunting absent, no change). According to conditional autoregressive models incorporating spatial autocorrelation, only farms and villages affected the presence of feces negatively in the island-wide data set. The effect of hunting on the presence of feces was present only in the north and east and the effect of conifer plantations was present only in the west. Qualitative comparisons of the census records from the 1990s with the more recent census indicated that feces were no longer found in the private land near the northern villages of Yakushima, where macaques were previously often detected in the 1990s. In other areas, such as near the southern villages or in the highlands, macaques were detected both in the 1990s and in 2017-2018. Our results further strengthen the possibility that the macaques have largely disappeared around the villages in the northern and eastern areas. Since the damage of crops by macaques has recently reduced considerably, we recommend reducing hunting pressure in the north and east areas and putting more effort into alternative measures such as the use of electric fences.
Direct observations of the behavior of wild Japanese macaques (Macaca fuscata) in many populations have been recorded over the decades. However, novel behaviors continue to be reported. Here, I report a novel social behavior “rump-rump contact” among males of one group in Yakushima, a behavior that has not been reported in any macaque species. Eight cases of this behavior were observed in 87 observation-days between August and October 2018. They were classified into two types: the RR type, where the rumps of the two individuals symmetrically touched each other, and the RT type, where the rump of one individual was in touch with the lateral torso of the other. At the same time as this behavior, the two individuals clasped the other's body and touched the other's hindquarter by wagging tails. The contexts in which this behavior was observed suggests that it helps in regulating social tension, as might be the case in bonobos where the RR type is known. However, it is likely that this behavior in the two species is not entirely comparable, as no genital contacts with thrust was observed in the Japanese macaques as part of this behavior. In the macaque, it is possible that this behavior was derived from “presenting” because it was seen just before this behavior, and the same action of clasping the other's body was seen at the same time as this behavior. This is a highly novel behavior in that, wagging tails may be a kind of tactile communication, which has never been reported in nonhuman primates. Additionally, it is valuable that this behavior previously known only in bonobos and chimpanzees was also observed in the Japanese macaques, which have very different phylogenetic relationships and social systems. Further studies may reveal the affinitive relationships that goes beyond the strict dominance relationship between males.
Modern primatology began in 1952-3 through artificial feeding of Japanese macaques at Koshima and Takasakiyama. Artificial feeding allowed short-distance observation, individual recognition and long-term observation. These new methods applied to wild monkeys made possible new findings, such as life-time kinship bonds, social organization, cultural behaviors, etc., which changed anthropology, biology, psychology and also other social sciences.
During the 1st stage of the studies led by K Imanishi and J Itani, researchers focused their efforts not on biology but on sociology. Itani declared that Japanese primate studies do not reflect natural science. On the other hand, some other researchers carried out ecological studies of monkeys and proceeded on to socioecology. Itani attributed the dominance relations among individuals to the social order or hierarchy, whereas other researchers did so to competition over resources to increase reproductive success.
In 1956 and in 1962, respectively, the Japan Monkey Centre and the Kyoto University Primate Research Institute were established. JMC contributed as the first organization of primatology in Japan, and KUPRI added to a confluence of field and experimental primatology. DNA fingerprinting to analyze the relatedness of individuals accelerated the unification of field and laboratory studies.
After 1970, agricultural damage caused by wild monkeys exploded due to deforestation and the presence of unguarded crops. Researchers had to work to prevent such monkey activity in the field. They were also forced to cull this endemic primate species. As a result, the field of primatology had to expand in cognitive science, physiology, brain science and genetics as well as conservation activity.
In school, students often experience a gap between theory and practice in many scientific subjects. A national assessment on academic ability in Japanese compulsory education has revealed a decline in students' motivation, achievement, and satisfaction towards science. To counter this, the Primate Society of Japan has promoted various primatology school programs by organizing visiting lectures and poster presentation awards at annual conferences since 2013. As a new endeavor to encourage primatology in school, the “High-school Student Meeting on the Environment in Kumamoto” was held on July 12th, 2019. Twenty-five students participated in a debate about current conflicts and future coexistence with Japanese macaques, as well as the anthropogenic impacts on wild orangutan populations by world-wide food supply chains. Student participants displayed sophisticated debate skills and dedicated attitudes towards tackling global environmental issues, impressing audiences and suggesting a high potential for the success of a student initiative in Kumamoto. The experience also enhanced the understanding of different educational systems. School students are often too busy to pursue their interests in depth, in part because of the curriculum system. Knowing this, we must design collaborative research programs closely with schools and improve their accessibility by encouraging fewer tasks and high flexibility. Following the meeting, we are now preparing a prefecture-wide questionnaire of Japanese macaque sightings to be available as an online wildlife and habitat survey application. We hope that this will lead to a fauna-flora database covering a broad area and various species, and that a voluntary citizen science project can be developed to further monitor biodiversity.