Do several species of Gorillas exist?

In former times, all gorillas were classified as one species, Gorilla gorilla, with three subspecies. A few years ago, experts decided to separate two species: eastern and western gorillas. They recognize 4 subspecies. The western lowland gorilla occurs in West Africa (Gorilla gorilla gorilla), the Cross River Gorillas (Gorilla gorilla diehli) at the Nigerian/Cameroonian border; the mountain gorilla (Gorilla beringei beringei) lives in the Democratic Republic of the Congo, Rwanda and Uganda on the Virunga Volcanoes and in the Bwindi forest, and Grauer's gorilla or eastern lowland gorilla (Gorilla beringei graueri) in the eastern Democratic Republic of the Congo.

Externally, the species differ in several characteristics. The nose of the western gorillas is broader than in the eastern populations. The silvery back of adult males extends to hips and upper thighs in the western gorillas. The mountain gorillas of the Virungas have shorter arms and very long, silky hair, mainly on the arms. While the hair of the eastern species is usually deep black (apart from the silvery back of the males), the western gorillas' hair can take on a grey or brownish tinge in both males and females.