All subspecies of the common chimpanzee, Pan troglodytes, including the western chimpanzee, P. t. verus, are currently categorised as Endangered (A4cd) by the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN), which means that they face a high extinction risk in the wild (Oates et al. 2008). In addition, the species is included in CITES Appendix I, which in effect prohibits its international trade (UNEP-WCMC 2011).

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Chimpanzee taxonomy remains an active area of research. Four subspecies are presently recognized: the Western Chimpanzee Pan troglodytes verus; the Nigeria-Cameroon Chimpanzee P. t. ellioti; the Central Chimpanzee P. t. troglodytes; and the Eastern Chimpanzee P. t. schweinfurthii (Oates et al. 2008; Oates 2011). The subspecies found in Sierra Leone is the Western Chimpanzee, which occurs from Senegal in the west to the Dahomey Gap or perhaps the Niger River in the east (Butynski 2003; Gonder et al. 2006; Hill 1969; Kormos & Boesch 2003).