 The bossou chimpanzee community consists of about 12 individuals and has been studied by Japanese researchers for three decades.Bossou chimps are well known to use a pair of stones as hammer and anvil to crack open oil-palm nuts.Long-term research on wild chimpanzee tool use revealed interesting topics like handedness of use of a hammer, critical period of learning nut-cracking at around 3 to 5 year old, "education by master-apprenticeship " and observational learning, possession of stones, deception, new tool use like algae-scooping, use of leaves for cushions, cultural variation in adjacent communities, etc.