Gorillas are the main herbivorous apes living in the forests of central sub Saharan Africa. Gorillas are divided into two species: the eastern gorilla and the western gorilla (both critically endangered), and four or five subspecies. They are the largest living primates. Gorilla DNA is highly similar to human DNA, ranging from 95% to 99%, depending on the number counted, and they are the second closest human relatives after chimpanzees and Bo chimpanzees.

Gorilla's natural habitat covers tropical or subtropical forests in sub Saharan Africa. Although they cover a small part of Africa, gorillas cover a wide range of altitudes. Gorillas live in the cloud forest in the Great Rift Valley of Virunga volcano at an altitude of 2200 – 4300 meters (7200 – 14100 feet). Lowland gorillas live in dense forests, lowland swamps and swamps as low as sea level, western lowland gorillas live in Central West African countries, and eastern lowland gorillas live on the border between the Democratic Republic of Congo and Rwanda.

Gorillas walk back and forth through their knuckles, although sometimes their feet carry food or are in a defensive position when they walk. Male gorillas weigh 135 to 195 kg (300 to 430 lbs) and adult females typically weigh 70 to 115 kg (150 to 250 lbs), half the weight of adult males. Adult men are 1.5 to 1.8 m (4 ft 11 in to 5 ft 11 in) tall and have arms spanning 2.3 to 2.6 m (7 ft 7 in to 8 ft 6 in). Female gorillas are shorter and have smaller arms. Groves (1970) calculated that the average weight of 47 wild adult male gorillas was 143 kg, while Smith and Jungers (1997) found that the average weight of 19 wild adult male gorillas was 169 kg. Adult male gorillas are known as silverback gorillas because of the characteristic silver hair on the back reaching the buttocks. The tallest gorilla ever recorded was a 1.95 m (6 ft 5 in) silver back, 2.7 m (8 ft 10 in) wingspan, 1.98 m (6 ft 6 in) chest and 219 kg (483 lb) weight, shot at alimbongo in northern Kivu in May 1938. The heaviest gorilla ever recorded was a 1.83 m (6 ft 0 in) silver back shot in Ambam, Cameroon, weighing 267 kg (589 lb). Captive males are said to weigh 275 kilograms (606 pounds). The face structure of gorilla is described as protrusion of mandible, that is, the mandible protrudes further than the upper jaw. Adult males also have sagittal GIT.