The Taï Chimpanzee Project (TCP) was initiated in 1979 to obtain data on rainforest-living chimpanzees, as only chimpanzees in the woodland savanna of Gombe and Mahale National Park were known. Introducing ecology into the discussion on chimpanzee behavioural diversity, we identified human poaching and leopard hunting as important ecological pressures. Over 40 years, the TCP overcame two civil wars, recurrent poaching and the dramatic impact of Ebola, anthrax and respiratory diseases. The project habituated three neighbouring chimpanzee communities, integrating many local students and assistants to ensure continuity of data collection and the security of chimpanzees, even in times of extreme political instability. Taï National Park has become an island within a huge cocoa and coffee plantation, which the chimpanzees and the TCP survived thanks to the extreme dedication of local and international project members, a project-specific law enforcement programme, a complete health monitoring programme, and the support of local human populations. Taï chimpanzees have become famous for their nut-cracking behaviour, high level of cooperative hunting and extensive cultural diversity.