Mount Nimba Strict Nature Reserve lies within Guinean Forests of West Africa Biodiversity Hotspot. It harbours an especially rich flora and fauna, and it is the home of more than 2000 vascular plant species, 317 vertebrate species, 107 of which are mammals, and to more than 2,500 invertebrate species. The reserve is a subject of biological surveys, because there are still large numbers of unknown species. Notably endemic vertebrates are Nimba viviparous toad (Nimbaphrynoides occidentalis), Lamotte's roundleaf bat (Hipposideros lamottei), and Nimba otter shrew (Micropotamogale lamottei). Other rare and endangered animals are West African lion (Panthera leo senegalensis), pygmy hippopotamus (Choeropsis liberiensis), zebra duiker (Cephalophus zebra), and western chimpanzee (Pan troglodytes verus) that uses stones as tools.