Contents The Ants of Africa
The Mt Nimba area of Guinea and Ivory Coast




Research site


Geo. Bossou

Research Team

Chimp. Beh.


Field Info



Name of Chimps(PDF)



Members of the Bossou research team have also been carrying out surveys and studies of neighboring chimpanzee populations in Séringbara and Yéalé in the Nimba Mountains and Yossono and Nonah, in the Diécké Reserve.

The Nimba Mountains
The Nimba Mountains are located directly to the southeast of Bossou. Nimba is situated 230 km northwest of the Tai Forest, where a community of chimpanzees has been intensively studied since 1976 (Boesch, 1978).

The Nimba Mountains were established as a nature reserve in 1943 in Côte d'Ivoire, and in 1944 in Guinea. The nature reserve on the Côte d'Ivoire side is a "foret classee", under national ownership. The Guinea portion of the massif was accepted as a biosphere reserve in 1980, consisting of 17,130 ha. Both reserves now form a World Heritage Site, gazetted in 1981 for Guinea and in 1982 for Côte d'Ivoire.

The reserve extends over 220 sq. km and its highest peak, Mont Richard Molard, is at 1752 m. The reserve on the Guinean side extends over 13,000 ha and 5,000 ha on the Côte d'Ivoire side. The Nimba Mountains are cut up by deep, richly forested valleys. There is great topographical diversity, with valleys, plateaux, rounded hilltops, rocky peaks, abrupt cliffs and bare granite blocks, and the whole area constitutes a vast water catchment.

The Nimba Mountains have attracted the interest of scientists, including geographers, geologists, soil experts, botanists, zoologists and other specialists ever since the late 1930's (Kortlandt, 1986). Botanical, zoological and geological inventories have consequently been completed. The single most important work, a comprehensive and extensive record of the flora of the Nimba Mountains, was produced by Adam (1971-1983).

The Nimba Mountains are characterized by evergreen forest of medium altitude (Guillaumet & Adjanohoun, 1971). The region below 800 m is entirely covered by primary tropical forest and, above 800 m, where the mountain becomes steeper, the vegetation is interspersed with montane forest and patches of high terrestrial herbaceous vegetation and savanna.

Thus, there are three vegetation types which dominate the Nimba mountains (WCMC, 1982):
1) High altitude grassland near the summit and woody plants on the slopes, which are absent from the ridges; interspersed with patches of montane forest, dominated by Myrtaceae species, and Marantaceae and Zingiberaceae growth.
2) Savanna varying depending on the hardness and geological structure of the soil and supporting numerous herbaceous plant communities. The savanna is broken by gallery forests between 1,000m and 1,600m. Parinari excelsa is a dominant species above 1,000m, where there is also an abundance of epiphytes.
3) Predominantly primary forest, located mainly on the foothills and in the valleys, with dominant species including Triplochiton scleroxelon, Chlorophora regia, Morus mesozygia, Terminalia ivorensis, Lophira procera, Tarrieta utilis, Chrysophyllum gambia (perpulchrum), and Mapania spp. Drier mid-altitude forests with trees such as Triplochiton scleroxelon, Piptadeniastrum africanum, and Parkia bicolor are also found most commonly on the steeper slopes of the massif on the Côte d'Ivoire side. More than 2,000 plant species have been described from the Nimba region, and about 16 are thought to be endemic (Adam, 1971-1983). The area has, as a result, been identified as a center of plant diversity under the IUCN-WWF Plants Conservation Program (IUCN/WWF, 1988).

The Governments of both Guinea and Côte d'Ivoire have also organized since 1982 various missions and training conferences together with UNESCO in order to redefine the problems of ecosystem protection in the Nimba Mountain region (Pascual et al, 1988; Pascual et al, 1989). All these publications and missions have enormously contributed to scientific knowledge of various species of fauna (Lamotte, 1982) and flora (Fournier, 1987; Schnell, 1987), and soils found in the Nimba Massif. Since 2001, Fauna and Flora International has also supported Tripartite Meetings between Liberia, Guinea and Côte d'Ivoire in order to promote a more efficient and harmonious management of the entire Nimba Mountains' region.

Séringbara, Guinea{short description of image}
The village of Séringbara (latitude 7°37'81 N and longitude 8°27'73 W) is located at the foot of the Nimba Mountains on the Guinean side, only 6 km to the southeast of Bossou. Two very basic campsites (the Gahtoy camp: latitude 7°39'57 N and longitude 8°25'08 W, and the Kiepa camp), which serve as our bases, were established within the reserve.

Shimada (2000) had previously provided confirmation of the occurrence of chimpanzees in the region, after two short surveys of the area in 1999, during which nests and feeding remains of chimpanzees were found in the forest beside the village. Indeed, over 70 nests were then found in the area. In addition, vocalizations of chimpanzees were frequently heard. This strongly suggested the presence of a resident group at this site. This was further confirmed during Matsuzawa's and colleagues' visit to the Séringbara forest in January and February 2000 and Humle visits to this site between June and September 2000 and June and September 2001, during which they recorded further evidence of chimpanzees in the area, including nests, feeding remains and indications of tool use (Humle and Matsuzawa, 2001).

{short description of image}During Humle's surveys of the site, minimum nesting group size was one and maximum was 21, therefore if infants are included, group size must be at least 30 individuals, assuming that at least nine adults females were present and carrying infants. Perhaps one or two more chimpanzee groups reside in the forest above the Séringbara village on the mountain slopes, but only further research will confirm exact group numbers and size.

There is no immediate threat to chimpanzees in this region, although some poaching is still going on in the reserve but not aimed at chimpanzees. Poaching incidences have reduced in frequency over the last three years. Fires in the dry season may be affecting the distribution of the chimpanzees but their influence has not yet been established. Local people (Manon) in the Séringbara and Bossou area consider the chimpanzee as the reincarnation of their ancestors and therefore the chimpanzee in this region benefit from some protection by indigenous people.

Yéalé, Ivory Coast
The village of Yéalé (7°32' N and 8°25' W) is located 12 km, southeast of Bossou, on the other side of the Nimba Mountains in Côte d'Ivoire. Matsuzawa and Yamakoshi established this study site in 1993. Since 1993, a plan of habituation of the chimpanzees in that area has been in progress, in collaboration with a local agent of the "Centre des Eaux et Forêts" of Danane. Preliminary surveys, carried out in the region, and information from local people reveal that maybe three groups of chimpanzees reside in the area, each one adjacent to one of three major rivers found in the Reserve - the Nuon, the Yan and the Toua. Humle has been continuing more intensive research at this site since 1999. A main campsite has been established within the reserve (Yanleu Camp, 7°33' N and 8°28' W), three and half hours walk from the village.

Goera (Gouela), Côte d'Ivoire
The Goera (Gouela) site (7°37'N and 8°22'W) is located 15km, southeast of Bossou, on the other side of the Nimba Mountains near the border with Côte d'Ivoire. Sugiyama saw chimpanzees in Goera and studied their nests and confirmed presence of ant-dipping in 1991 (Sugiyama et al., 1995). In 1999, Shimada surveyed this area again and further confirmed chimpanzee presence (Shimada, 2000). Traces of human activity and snares in the forest and the cautious behavior of the chimpanzees suggest presence of poaching at this site.


Diécké, Guinea
{short description of image}The Diécké forest or "Forêt Classée de Diécké" is located about 50 km to the west of Bossou. It is a reserve extending over 700 sq. km in area, stretching about 35 km from north to south and 35 km from east to west. The forest is under the control of the "Centre Forestier" of N'Zérékoré. The two study sites, which we have surveyed thus far, are located beside two villages: Yossono (west of the reserve, 7°38' N and 8°30' W) and Nonah (east of the reserve (7°33' N and 9°05' W)). The explored sites consist primarily of primary forest covering small hills, of which the highest peak is at 589 m above sea level (Matsuzawa et al., 1999). It still remains undetermined as to how many chimpanzees inhabit this reserve and how many communities pervade in the area. But some preliminary behavioral data have emerged, especially concerning tool-use at those sites (cf. Humle and Matsuzawa, 2001). There were recent reports of hunting of chimpanzees in the Yossono area dating back to July 2001, while hunting pressure at Nonah does not appear to be as high. But hunting seems to be a huge problem within this Reserve and may pose a considerable threat to the chimpanzee populations living in that region.