Western Gorillas
Western lowland gorillas feed on grasses, herbs and sedges that thrive in forest clearings and gaps in the canopy, and so are often found in areas of secondary forest. Social organisation takes the form of single-male harems, with female transfer and male emigration at maturity. At Mbeli Bai in the Nouabale-Ndoki National Park in northern Congo, group size varies from two to sixteen, with an average group size of 9.4 individuals. Females often transfer to another group before breeding, usually when they become adolescent at around eight years old, and sometimes transfer several times during their life. Females do not usually form bonds with other females, but bond instead with their own offspring and the group silverback, so that the silverback is the cohesive influence that holds the group together. When a silverback dies, groups typically disintegrate and females immigrate into new groups.
IUCN identifies trade, habitat loss and hunting and collecting as the main threats to the gorilla. The Ebola virus also presents a potent threat to some of the largest remaining western gorilla populations in the world. The commercial bushmeat trade is flourishing in several African countries, and some cultures favour gorilla meat because consumers are reputed to take on the strength of the gorilla when they eat the meat. In some parts of their range gorillas come into conflict with humans, especially where they raid crops, but most of their range lies across areas which are thinly populated by humans and often inaccessible. The western lowland gorilla is Integrally Protected in Congo.
When males reach maturity, they usually leave their natal group and become solitary, before eventually acquiring females of their own. In contrast to mountain gorillas, multi-male groups with more than one silverback are rarely observed in western gorillas.