Eastern gorillas live in stable, cohesive family groups, led by a dominant silverback male. Eastern gorillas tend to have larger group sizes than their western relatives, exceptionally numbering more than 50 individuals (2). There is no distinct breeding season and females give birth only once every three to four years due to the gestation period of 8.5 months and a long period of parental care. Newborn gorillas have greyish-pink skin and can crawl after nine weeks; they are not fully weaned until 3.5 years (2). Males defend their females and offspring using their large size in intimidating displays involving charging and chest-beating (2).
Eastern gorillas are herbivorous, with a heavily foliage-based diet (2). They have smaller home ranges than western gorillas as foliage is more abundant than fruit. They are diurnal but most foraging occurs in the morning and late afternoon. At night they build nests by folding over vegetation, usually on the ground (2).