Effects of a Typhoon on Foraging Behavior and Foraging Success of Macaca fuscata on Kinkazan Island, Northern Japan

Abstract

We studied the effects of typhoon damage on the food habits, time budgets, and moving distances of Japanese macaques (Macaca fuscata) on Kinkazan Island, northern Japan. Before the typhoon (pre-typhoon phase), the macaques fed on various food items, including fruit in trees (Swida macrophylla) and nuts (Torreya nucifera) on the ground. After the typhoon passed (post-typhoon phase), the macaques fed intensively on the seeds of Perilla frutescens (a forb) and the nuts of Quercus serrata on the ground. One may attribute the changes to decreased food availability or foraging efficiency of fruits and nuts on the ground, due to their concealment by leaf litter and mud and their consumption by other animals, such as sika deer (Cervus nippon) and field mice (Apodemus argenteus). In the post-typhoon phase, the macaques fed more quickly on seeds of Perilla frutescens, spent less time traveling, and moved over shorter distances. The differences may be due to changes in the distribution of staple foods between the 2 phases. We also evaluated the energy intake and energy balance of the macaques in both phases, based on observations of foraging and nutritional analyses of the food items. There is no significant difference in either parameter between the 2 phases. The changes in food habits and movement behavior may have compensated for the reduced food availability or foraging efficiency caused by the typhoon. Both behavioral changes and nutritional issues are important when investigating the effects of storms on animal ecology.