Abstract
The behavior of chimpanzees of Bossou has been studied since 1975. The core-area of the Bossou chimpanzees was then separated about 6km from that of adjacent chimpanzee groups by savanna, though lone chimpanzees may sometimes have passed through. From the middle 1980s expansion of cultivated fields began to destroy the forests of the chimpanzees and the adjacent chimpanzees gradually disappeared. The rebellion in Liberia, which occurred by the end of 1989, produced many refugees, who came to Bossou and other villages near the frontier. The number of Bossou chimpanzees has decreased since 1990. The Government of Guinea decided to estab-lish a forest reserve enclosing the core-area of Bossou chimpanzees. The Japanese Government also decided to help establishment of the Bossou Institute of Environmental Research to promote research and conservation efforts.
