They are found mostly in lowland rain forest and occasionally in mountainous rain forest. They are almost totally vegetarian, eating leaves shoots, and stems, supplemented by wood, roots, flowers, and grubs. The females give birth to a single young every few years. Some individuals have lived 50 years or more. They are mostly terrestrial, though they can climb well enough.
Adult males spend most of their time on the ground because of their weight.
They are diurnal, and sleep in crude nests either in trees or on the ground. The troops are partly territorial. In captivity, gorillas have exhibited very intelligent behavior and a few have even been taught to speak basic sign language. They are endangered due to habitat destruction.