The two chimpanzee species are separated by the huge Congo River. Its formation 1.5–2 million years ago may have led to the speciation of the bonobo. Their population is between 29,000 and 50,000 individuals. The species is listed as Endangered on the IUCN Red List. It is threatened by habitat destruction, human population growth and commercial poaching. The bonobo lives for about 40 years in captivity, though its lifespan in the wild is unknown.