Bossou 30 Years

Tetsuro Matsuzawa
Primate Research Institute, Kyoto University

This article provides a report on an international symposium held in Guinea in 2006 and will briefly summarize the current situation of a small group of chimpanzees living near Bossou in Guinea, West Africa. Bossou is a village located west of the Nimba Mountains, the only World Natural Heritage site (UNESCO/MAB) in Guinea. French and Dutch scholars had carried out early studies of the fauna and flora —including chimpanzees— of this area1. In 1976, Yukimaru Sugiyama launched a long running field study of the Bossou chimpanzees2. Since then, many researchers from the Primate Research Institute of Kyoto University (KUPRI) have made contributions to a joint effort to study the chimpanzees and to promote the conservation of their habitat3. Bossou chimpanzees are well known to use a variety of different tools, including the use of a stone hammer and stone anvil for cracking open oil-palm nuts4. Other unique examples of tool use in the repertoire include pestle pounding5, and ant-dipping6.

KUPRI organized an international symposium celebrating the 30th anniversary of chimpanzee research at Bossou in association with two Guinean public institutions, DNRST (Direction Nationale de la Recherche Scientifique et Technique) and IREB (Institut de Recherche Environnementale de Bossou), the official counterparts of the scientific collaboration between KUPRI and Guinea that began 30 years ago. The international team of researchers called KUPRI-International is carrying out long running studies of Bossou-Nimba chimpanzees based on a formal convention with the two Guinean authorities. The symposium was entitled “Research and Conservation of the African Great Apes: The 30th Anniversary of the Bossou-Nimba Project”. The symposium was held from 27 to 29 November, 2006, in Conakry, the capital of Guinea. The first two days, during which oral presentations were delivered, were held at the Hotel Riviera Palace, while the third day consisted of a film festival at the Franco-Guinean Cultural Center. The official language was French throughout the entire period. The symposium was opened by an address from the Minister of Higher Education and Scientific Research, followed by a speech by the Japanese ambassador, Mr. Rinzo Kataoka. Dr. Tamba Tagbino, vice director of the DNRST, presented a summary of the collaboration between the two countries, Japan and Guinea, in terms of the scientific research of chimpanzees at Bossou, Nimba, and the surrounding areas. There were three plenary talks. Yukimaru Sugiyama talked on the 30 years research of Bossou chimpanzees. Tetsuro Matsuzawa talked on the current program of Bossou-Nimba research and the green corridor project. William McGrew of Cambridge University gave a plenary talk to illuminate the unique contribution of the long running studies at Bossou to international primatology.

The sessions that followed focused on the various studies of chimpanzees at Bossou and Nimba by the KUPRI-International team. The speakers were as follows: Gen Yamakoshi (Kyoto University, Japan), Tatyana Humle (University of Wisconsin, USA), Dora Biro (Oxford University, UK), Claudia Sousa (Lisbon New University, Portugal), Gaku Ohashi (KUPRI, Japan), Katelijne Koops (Cambridge University, UK), Kimberly Hockings (Stirling University, UK), Kazunari Ushida (Kyoto Prefectural University, Japan), Asami Kabasawa (Kyoto University, Japan), Nicolas Granier (University of Liege, Belgium), and Susana Carvalho (Lisbon University of Technology, Portugal). The symposium also included talks on topics related to the research at Bossou: baboons in Guinea by Marie-Claude Huynen (Liege University, Belgium), the conservation efforts of chimpanzees in Guinea by Christine Sagno and Sedibinet Sidibe (Guinea), and the tree nursery for the green-corridor project in Bossou and Nimba by Makan Kourouma (IREB, Guinea). There were four other guest speakers from different parts of Africa, addressing the following topics: conservation efforts, especially environmental education, in Guinea and Gambia by Janis Carter (Gambia), chimpanzees in eastern Congo by Augustin Basabose (DRC), chimpanzees of the Mahale Mountains in Tanzania by Michio Nakamura (Japan), and chimpanzees in Liberia by Joel Gamys (CI, Libieria). There were about 80 participants of the symposium (Fig.1).

Fig. 1. Group photo of invited speakers of the international symposium held in Conakry (Photo provided by KUPRI-International).

The film festival on the third day was open to the public. Four films were shown: “A hard nut to crack”, made by ANC/NHK, illuminating developmental changes in stone-tool use by Bossou chimpanzees, “Jokro: The death of an infant chimpanzee” by ANC focusing on a chimpanzee mother carrying the mummified body of her dead infant, “Return to the Great Apes Planet: the Chimpanzees of Bossou” by TF1/WLP/Ushuaia, and “Le Pacte de Bossou” by France3/Gaia-Video-Concept documenting the unique coexistence of humans and chimpanzees at Bossou. All films were shown with French narration, and after each presentation Tatyana Humle answered questions posed by the audience.

After the symposium in Conakry, some of the participants traveled to Bossou, 1,050 km from the capital. A ceremony was held on site, on the 3rd of December, to commemorate the project’s 30th anniversary. The Manon people of Bossou village acted as the hosts of the ceremony, joined by the Guinean and foreign researchers and their local assistants. The Manon has a religious belief that their ancestors are the chimpanzees that inhabit the sacred forest of Mont Gban behind the village. The chimpanzee is one of the totems of the Manon family that founded Bossou village. The ceremo- ny of Mont Gban incorporated performances by three masked men and traditional dancing accompanied by drumming.

Bossou chimpanzees are very unique: they are not afraid of humans and coexist peacefully with them (Fig. 2). This is in part due to the attitude of the local Manon people and partly to the long-running habituation by the researchers. Bossou is home to about 2,500 villagers. The chimpanzees live in the secondary forests of the hills surrounding the village, so that they have to cross roads to move from one part of the forest to another7. Over the past 30 years, the number of chimpanzees in the Bossou community has been stable at around 19 individuals on average (range: 16–22). However, there was a flu-like epidemic in November 2003 and we lost five chimpanzees within a short time8. The number of Bossou chimpanzees is now 12, stable over the past three years. We have been applying strict rules to protect this precious community: we always keep our distance from the chimpanzees, limit the number of tourists, wear masks during observation, and so forth. Bossou is located only 4 km from the border to Liberia and 8 km from the border of Cote d’Ivoire. The two neighboring countries were recently shaken by civil war and many refugees fled into the Bossou area. Bossou chimpanzees also occasionally range into Liberia. The KUPRI-International researchers, in collaboration with IREB, the villagers, and local NGOs, initiated a reforestation program called the Green Corridor Project (Projet Corridor Vert) in 19979. This project has the aim of planting trees to enlarge the forests of Bossou and create a corridor over the savanna that separates the hills of Bossou from the Nimba Mountains. In Nimba, there is another community of chimpanzees, with the unique culture of making ground-nests10. The green corridor aims to connect the fragmented forests of Bossou to the large primary forest in Nimba in order to secure the exchange of individuals with adjacent communities. Bossou chimpanzees have been utilizing the forests of the Nimba mountains more and more frequently. The KUPRI-International team, in collaboration with the Guinean authorities DNRST and IREB, will make continuous efforts to monitor the Bossou chimpanzees and to promote conservation efforts in the area. Please visit the following web site for further information: http://www.greenpassage.org.

Fig. 2. Chimpanzees at Bossou cracking nuts with stone tool (Photo by E. Nogami)

Acknowledgment: The symposium was finan- cially supported by Kyoto University, KUPRI, and JSPS-HOPE program.


  1. Kortlandt A 1986. The use of stone tools by wild-living chimpanzees and earliest hominids. J Hum Evol 15: 77–132.
  2. Sugiyama Y, Koman J 1979. Social structure and dynamics of wild chimpanzees at Bossou, Guinea. Primates 20: 513–524.
  3. Matsuzawa T 2006. Sociocognitive development in chimpanzees: A synthesis of laboratory work and fieldwork. In: Cognitive Development in Chimpanzees, Matsuzawa T, Tomonaga M, Tanaka M (eds.), Springer, Tokyo, pp. 3–33.
  4. Biro D, Inoue-Nakamura N, Tonooka R, Yamakoshi G, Sousa C, Matsuzawa T 2003. Cultural innovation and transmission of tool use in wild chimpanzees: evidence from field experiments. Anim Cogn 6: 213–223.
  5. Yamakoshi G, Sugiyama Y 1995. Pestle-pounding behavior of wild chimpanzees at Bossou, Guinea: A newly observed tool-using behavior. Primates 36: 489–500.
  6. Humle T, Matsuzawa T 2002. Ant-dipping among the chimpanzees of Bossou, Guinea, and some comparisons with the other sites. Am J Primatol 58: 133–148.
  7. Hockings K, Anderson J, Matsuzawa T 2006. Road crossing in chimpanzees: A risky business. Curr Biol 16: 668–670.
  8. Matsuzawa T, Humle T, Koops K, Biro D, Hayashi M, Sousa C, Mizun Y, Kato A, Yamakoshi G, Ohashi G, Sugiyama Y, Kourouma M 2004. Wild chimpanzees at Bossou-Nimba: Deaths through a flu-like epidemic in 2003 and the green-corridor project. Primate Res 20: 45–55.
  9. Hirata S, Morimura N, Matsuzawa T 1998. Green passage plan (Tree planting project and environmental education using documentary videos at Bossou: A progress report. Pan Afr News 5: 9–11.
  10. Koops K, Humle T, Sterck E, Matsuzawa T 2006. Ground-nesting by the chimpanzees of the Nimba Mountains, Guinea: Environmentally or socially determined? Am J Primatol 65: 1–13.

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