Despite 11 years of civil war in Sierra Leone, it appears that the mammal fauna of the project zone has survived relatively intact and that the project zone continues to be an important site for the conservation of threatened Upper Guinea forest wildlife, and the most important site for these species in Sierra Leone. No large mammal species was extirpated during the war and previously unrecorded species have been discovered in recent years. Some of the most threatened species continue to have healthy populations in the forest, especially primates, and showed little or no sign of reduced abundance. However, the population of African forest elephants has collapsed during the war, with only a few individuals remaining from approximately 110 in the mid-1980s (Lindsell et al 2011).
Eleven primates are known to occur in the project zone, including one ape and three prosimians. The Endangered Western red colobus is common but is mostly restricted to the less disturbed areas of the central and northern parts of the project area. The Vulnerable Diana monkey, Sooty mangabey and Western pied colobus are abundant and widespread but the only Near-threatened primate, Olive colobus seems to be rare (Klop et al, 2008).