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 3 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 say that the Bwindi population in Uganda is a 3rd subspecies, though no description has been finished.
The Mountain Gorilla has longer and darker hair than other gorilla species, allowing it to live in hot or cold weather and travel into areas where temperatures drop below 32 degrees Fahrenheit (0 degrees Celsius). It has chosen a life on the ground more than any other non-human primate, and its feet most resemble those of humans. Gorillas can be identified by nose prints unique to each individual. Males usually weigh twice as much as the females, and this subspecies is on average the largest of all gorillas. 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 masseter muscles, which attach to the lower jaw, or mandible. Adult females also have these crests, but they are less pronounced.
Adult males are called silverbacks because a saddle of gray or silver-colored hair develops on their backs with age. The hair on their backs is shorter than on most other body parts, and their arm hair is especially long. Upright, males reach 1.5â€“1.8 m (5â€“6 ft) in height, with an arm span of 2.25 m (7 ft 5 in) and weigh 204â€“227 kg (450â€“500 lb). The tallest silverback recorded was a 1.94 m (6 ft 4 in) individual shot in Alimbongo, northern Kivu in May 1938 and the heaviest was a 1.83 m (6 ft) silverback shot in Ambam, Cameroon which weighed about 266 kg (590 lb).
The Mountain Gorilla is primarily terrestrial and quadrupedal. However, it will climb into fruiting trees if the branches can carry its weight, and it is capable of running bipedally up to 6 m (20 ft). Like all great apes other than humans, its arms are longer than its legs. It moves by knuckle-walking (like the Common Chimpanzee, but unlike the Bonobo and both orangutan species), supporting its weight on the backs of its curved fingers rather than its palms.
The Mountain Gorilla is diurnal, most active between 6:00 a.m. and 6:00 p.m. Many of these hours are spent eating, as large quantities of food are needed to sustain its massive bulk. It forages in early morning, rests during the late morning and around midday, and in the afternoon it forages again before resting at night. Each gorilla builds a nest from surrounding vegetation to sleep in, constructing a new one every evening. Only infants sleep in the same nest as their mothers. They leave their sleeping sites when the sun rises at around 6 am, except when it is cold and overcast; then they often stay longer in their nests.