They live in heavy rain forests, and it is difficult for scientists to accurately estimate how many survive in Cameroon, Central African Republic, Congo, Equatorial Guinea, Gabon, Angola, and the Democratic Republic of Congo.
Live on the ground in communities of up to 30 individuals. These troops are organized according to fascinating social structures. Troops are led by one dominant, older adult male, often called a silverback because of the swath of silver hair that adorns his otherwise dark fur. Troops also include several other young males, some females, and their offspring. The leader organizes troop activities like eating, nesting in leaves, and moving about the groups three-quarter- to 16-square-mile (2- to 40-square- kilometer) home range They can climb but usually tend not to because of their large size
Female gorillas give birth to one infant after a pregnancy of nearly nine months. Unlike their powerful parents, newborns are tiny—weighing four pounds (two kilograms)— and able only to cling to their mothers fur. These infants ride on their mothers backs from the age of four months through the first two or three years of their lives. Young gorillas, from three to six years old, remind human observers of children. Much of their day is spent in play, climbing trees, chasing one another, and swinging from branches.
Those who challenge this alpha male are apt to be cowed by impressive shows of physical power. He may stand upright, throw things, make aggressive charges, and pound his huge chest while barking out powerful hoots or unleashing a frightening roar. Despite these displays and the animals obvious physical power, gorillas are generally calm and nonaggressive unless they are disturbed.
In the wild, western lowland gorillas eat mostly fruit, leaves and other plant parts. In at least some areas, gorillas may eat termites and other small insects. In the Zoo, gorillas receive nutritionally complete primate chows plus a wide variety of fresh produce including oranges, apples, carrots, grapes, kale and other types of greens. They also receive puffed cereal, popcorn, raisins and seeds that are scattered outside in the grass or inside in hay to encourage foraging behavior.