Gorillas live exclusively in the tropical rainforests of Africa. Their distribution area is divided in two - almost 1000 km separate the western from the eastern gorillas. One distinguishes five subtypes today thanks to more recent genetic investigations:
In the west one finds the western lowland gorillas (Gorilla gorilla gorilla diehli) and the Cross River gorillas (Gorilla gorilla diehli), in the east the mountain gorillas of the Virunga volcanoes (Gorilla beringei beringei), the Bwindi gorillas (Gorilla berengei bwindi) and the eastern lowland gorillas (Gorilla beringei graueri).
Gorillas usually live together in harem groups: Several adult women and young animals gather around a silver back - so called after the grey coat colour that a male animal with sexual maturity develops on its back. The silverback provides order in the group and protects it against danger. Usually a group consists of 4 and 8 members, in one case even 52 animals were counted. If the silverback dies, this usually also means the end of the group - except a subordinate silverback man, usually the son of the former leader, takes it over.
