Straddling the border between Cameroon and Nigeria, in a handful of highland forest massifs, survives the world's most endangered gorilla subspecies: the Cross River gorilla (Gorilla gorilla diehli).
Fewer than 300 individuals are thought to remain in the wild, spread across roughly a dozen groups isolated from one another. Classified as 'critically endangered' by the IUCN, it ranks among the world's 25 most threatened primates.
Sources: IUCN, World Wide Fund for Nature (WWF).
