On the ground, gorillas normally move in a stooped posture, with the knuckles of the hands resting on the ground, but they do stand erect on occasion. Females and juveniles climb trees, but males rarely do so because of their great bulk. There may be some conflict with neighboring groups, but encounters are generally avoided by communications such as drumming on the ground from a distance. Old males will threaten rivals by standing erect and beating the chest while roaring and barking and sometimes by tearing up and throwing plants. When the leader of a troop dies, younger males contest for dominance.
Gorillas are active in the daytime.
The troop rises between 6 A.M. and 8 A.M., feeds for a while on plant material, such as leaves, buds, stalks, berries, bark and ferns, and then has a period of rest and relaxation. Gorillas do not appear to drink but get the water they need from their juicy diet. They feed again in the afternoon and then retire for the night in nests made of twigs and leaves. Young gorillas under 3 years old sleep with their mothers, but all others have their own nests. Breeding appears to take place at any time of year.