Abstract
We surveyed chimpanzees in the Nimba Reserve, which is located 10km away from Bossou and have not been studied much until now. Only one encounter and a small number of field signs were recorded. The chimpanzees are appeared to be very timid against humans. Their population density is thought to be low mainly because the hunting pressure by human is high, Regarding tool-using behavior, there were some interesting findings. Instead of oil-palm nuts of Bossou, a few other nuts were found cracked and are supposed to have been eaten by the chimpanzees. There seems to be cultural difference in tool use between Bossou and the Nimba Reserve.
