The Mountain Gorilla (Gorilla beringei beringei) is one of the two subspecies of the eastern gorilla. There are two populations. One is found in the Virunga volcanic mountains of Central Africa, within three National Parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga in the eastern Democratic Republic of Congo (DRC). The other is found in Uganda's Bwindi Impenetrable National Park. Some primatologists say that the Bwindi population in Uganda may be a separate subspecies, though no description has been finished. As of November 2012, the estimated total number of mountain gorillas is around 950.
The fur of the mountain gorilla, often thicker and longer than that of other gorilla species, enables them to live in colder temperatures. Gorillas can be identified by nose prints unique to each individual. Males, at a mean weight of 195 kg (430 lb) and upright standing height of 150 cm (59 in) usually weigh twice as much as the females, at a mean of 100 kg (220 lb) and a height of 130 cm (51 in). This subspecies is on average the second largest species of primate; only the Eastern Lowland Gorilla, the other subspecies of Eastern Gorilla, is larger. Adult males have more pronounced bony crests on the top and back of their skulls, giving their heads a more conical shape. These crests anchor the powerful temporalis muscles, which attach to the lower jaw (mandible). Adult females also have these crests, but they are less pronounced. Like all gorillas they feature dark brown eyes framed by a black ring around the iris.
The mountain gorilla inhabits the Albertine Rift montane cloud forests and of the Virunga Volcanoes, ranging in altitude from 2,200–4,300 metres (7,200–14,100 ft). Most are found on the slopes of three of the dormant volcanoes: Karisimbi, Mikeno, and Visoke. The vegetation is very dense at the bottom of the mountains, becoming more sparse at higher elevations, and the forests where the mountain gorilla lives are often cloudy, misty and cold.
The mountain gorilla is highly social, and lives in relatively stable, cohesive groups held together by long-term bonds between adult males and females. Relationships among females are relatively weak. These groups are nonterritorial; the silverback generally defends his group rather than his territory. In the Virunga mountain gorillas, the average length of tenure for a dominant silverback is 4.7 years. Although strong and powerful, gorillas are generally gentle and shy. Severe aggression is rare in stable groups, but when two mountain gorilla groups meet, the two silverbacks can sometimes engage in a fight to the death, using their canines to cause deep, gaping injuries. The entire sequence has nine steps: (1) progressively quickening hooting, (2) symbolic feeding, (3) rising bipedally, (4) throwing vegetation, (5) chest-beating with cupped hands, (6) one leg kick, (7) sideways running, two-legged to four-legged, (8) slapping and tearing vegetation, and (9) thumping the ground with palms to end display.
- Shelter: Ape Nest, Grass Umbrella, Tree Hut
- Enrichment: Easel, Jungle Gym, Monkey Bars, Tire Swing
- Animal Food: Apples, Bananas, Leaves, Mixed Fruits