Current western and eastern gorilla populations are divided by a distance of approximately 900 km (see map). The current and most accepted taxonomy for this geographical, morphological and genetic divide is to class these two forms of gorillas as two separate species: Gorilla gorilla in the west, and Gorilla beringei in the east. Each of these two species also contains two to three subspecies. In the west, there are Cross River gorillas (Gorilla gorilla diehli) and western lowland gorillas (Gorilla gorilla gorilla). In the east, there are Virunga mountain gorillas (Gorilla beringei beringei), Bwindi gorillas (subspecies unnamed, or some scientists believe it is the same subspecies as the Virunga gorilla, G. b. beringei), and finally Grauer's gorillas (Gorilla beringei graueri). Grauer's gorilla is sometimes called the “eastern lowland” gorilla, but we refrain from using this common name since it is misleading: the altitudinal range for Grauer's gorillas varies from 550 meters in the west of their range to almost 3000 meters on Mts. Kahuzi and Tshiaberimu. For a review of the rich and colorful history of gorilla taxonomy, the reader is referred to a recent article by Colin Groves.
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