In Japan, the Japanese macaque (Macaca fuscata) has serious damages to agricultural products and its activities around human settlements impacted the human life. Little is known about the troop size and home-range area of wildlife troops of Japanese macaques that cause crop damages in relation to environmental conditions. We used monitoring survey data of twelve troops on Honshu Island, the main island of Japan. In this study, the core area was used as an index of the home-range area, which was defined as 65% of the utilization area of macaques by the fixed kernel method. The relationship between explanatory and dependent variables was analyzed by single regression analysis, where the explanatory variable was inclination angle or snow cover and the dependent variable was troop size or core area.
Results/Conclusions
The analysis showed that there was no relationship between the troop size and home-range area for the troops in Fukui Prefecture which is often covered by heavy snow in winter. The troop size was shown to be negatively correlated with snow cover. The core area was positively correlated with inclination angle. Snow is known as one of the limiting factors for the survival of macaques, because food resources such as herbs and plant roots for the macaques are reduced under heavy snow conditions. The human settlements and cropland are located on flat grounds where a variety of food resources for macaques are potentially available. In contrast, food resources such as barks and nuts are sparsely distributed in forest sites on steep slopes. For these reasons, Japanese macaques in forest sites might have wider migration areas to gain necessary food resources than those living near human settlements. These results suggested that the troop size and home-range area of Japanese macaques in a snowy region were independent of each other and depended on climatic and geographical conditions.