Poster presentation 12th International Mammalogical Congress

How do deer achieve foraging success under intraspecific competition for food dropped by foraging macaques? (#612)

Yoshimi Agetsuma-Yanagihara 1 , Naoki Agetsuma 2
  1. Waku Doki Science Planning, Kozagawa, Wakayama, Japan
  2. Field Science Center for Northern Biosphere, Hokkaido University, Kozagawa, Wakayama, Japan

In an warm temperate forest of Yakushima, Japan, Yaku sika deer (Cervus nippon yakushimae) often gather under trees to obtain food dropped by foraging Yakushima macaques (Macaca fuscata yakui) in the branches above. We defined areas under the food trees as macaque-food patches (MFPs). In MFPs, agonistic interactions frequently occur for food among the deer. Thus, the deer develop foraging strategies to acquire food and counter intraspecific competition in MFPs. Their ability to compete varies among the age–sex classes. In addition, the condition of the dropped foods can be classified into two types (L-type, cluster of fruits and leaves attached to a branch; S-type, individual fruit and leaf dispersed over MFPs). Therefore, we predicted that their foraging strategy changes with the age–sex class and food type. We recorded residence time, food intake, and agonistic interactions of deer in MFPs. Agonistic interactions occurred more frequently in L-type MFPs than S-type MFPs. Adult males tended to stay in L-type MFPs for a longer period, frequently attack other deer, and achieve higher food intake speed. Young males also tended to stay for a longer period; however, they were frequently attacked, and they achieved middle food intake speed. Adult and young females tended to stay for a shorter period, were frequently attacked; however, adult females also tended to attack frequently. Further, adult females achieved lower food intake speed, although young females could obtain little food. The deer in MFPs appeared to apply different foraging strategies corresponding to their age–sex classes.