Gorillas feed on trees, up to 30 m above the ground. Animals adopt sitting and standing positions for feeding. They twist the branches within reach, often without breaking them. The fruits and leaves are picked with the lips or picked by hand and transferred to the mouth. When fruit abundance is low, adults also bend and break saplings to access foliage, fruit, or vines.

Due to its large size, G.beringei probably has only two major predators. Mainly people and diseases are the major reasons why mountain gorillas are endangered. Humans are the main predator of G.beringei, killing them for their meat, and body parts and in retaliation for crop damage. A few cases of G. beringei predation by Leopards panthera pardus are described.

Upon rising from their night nests, gorillas spread out to forage. The animals sit on their haunches or eat while walking. Gorilla b. beringei is terrestrial for 96% of feeding time. Adults climb for only 4% of feeding time, while immatures feed in trees 18% of the time. Adult males eat up to 30 kg of vegetation per day. There is little competition between individuals, as food is generally abundant.

In 1989 there were approx. 324 eastern gorillas G.b. beringei in Virunga Mts.A census of this population in 2000 led to an estimateof 359–395 individuals , while a 2003 census estimated 380 individuals. A census, taken in of 2010, produced an estimate of 480 individuals.

Western gorillas are endemic to western central Africa where they live; Gorilla g. gorilla is distributed over six or seven countries from south of Sanaga R. south through S. Cameroon, SW Central African Republic, mainland Equatorial Guinea (Rio Muni/Mbini), and Gabon, into extreme N. Angola (Cabinda enclave) to Congo R., and east into W. Congo and across the Sangha R. to about the Oubangui R. Western boundary is the Atlantic Ocean.

Due to its large size, the gorilla has only two major predators. Humans are by far the main predator of G. gorilla, killing animals for their meat, and body parts and in retaliation for damage to crops. Leopards are important predators at some sites, with G. gorilla accounting for 4–9% of biomass consumed. Gorilla gorilla, like G.beringei, is prone to many pests and diseases.

The majority of western lowland gorillas are in Gabon and Congo. Their number in Gabon was estimated at between 28,000 and 42,000 in the early 1980s. Congo had a similar number in 1989–1990. Cameroon held ca. 15,000 gorillas in 1998. Equatorial Guinea (Rio Muni/Mbini) supported >3000 G. g. gorilla in 2011. In 2009, the total number of western gorillas was estimated at >150,000.