Male mountain gorilla beating his chest. The mountain gorilla (Gorilla beringei beringei) is one of two subspecies of eastern gorillas. It inhabits the Virunga volcanic mountains of Central Africa and feeds mainly on leaves, shoots and stems of plants. Each troop of gorillas is lead by a single mature male known as the silverback. The silverback will often beat his chest to exert his dominance and warn of danger. Photographed in Volcanoes National Park, Rwanda.