Gorillas (Gorilla) are the largest of all primates. They are herbivorous, ground-dwelling apes that inhabit lowland and montane forests in eastern equatorial Africa and central Africa. In addition to being the largest of the apes, gorillas are also the most endangered. They face numerous threats including habitat loss, hunting and disease such as Ebola. Gorillas also inhabit regions of political instability where civil wars rage. This creates a dangerous environment for the gorillas and makes conservation efforts very difficult. Of all the gorilla subspecies, the Cross River gorillas are the most endangered. There are less than 300 Cross River gorillas living in the wild, making it one of the world's 25 most endangered primates.
Gorillas move by a method known as knuckle walking in which they walk on all four limbs. Their feet and hands touch the ground and they hold their fingers in a folded position so that their knuckles touch the ground. They can also walk bipedally for short distances.
Gorillas form social groups which are referred to as troups. Troups are structured around one adult male silverback (a term which refers to the silver patch of fur which forms on the back of a mature male).
Gorillas are a group of great apes that includes two species, the eastern gorilla and the western gorilla. Each of the two gorilla species are further subdivided into two subspecies. Eastern gorilla subspecies include the eastern lowland gorilla and the mountain gorilla. Western gorilla subspecies include the western lowland gorilla and the Cross River gorilla. Gorillas belong to the Homininae, a group of hominids that includes humans, chimpanzees and gorillas.
The closest living relatives of gorillas are chimpanzees and humans. Gorillas and the other members of the Hominidea—a group that includes orangutans as well as humans, chimpanzees and gorillas—diverged from a common ancestor 7 million years ago.