The mountain gorilla is one of the two subspecies of gorillas. Gorillas are ground-dwelling, predominantly herbivorous apes that inhabit the forests of East Africa. There are two populations. One is found in the Virunga volcanic mountains of East Africa within three National Parks: Mgahinga National Park, in south-west Uganda, Volcanoes in north-west Rwanda and Virunga in the eastern Democratic Republic of Congo (DRC). The other is found in Uganda’s Bwindi Impenetrable National Park. Some primatologists consider the Bwindi population in Uganda as may be a separate subspecies though no description has been concluded to ascertain this.
Few animals have sparked the imagination of man as much as the gorilla, the largest of the living primates and the last member of the ape family known to science. Most gorillas live in inaccessible regions in various dense forests in tropical Africa, and only in the last 30 years have scientists learned details of their life in the wild.
A chain of eight volcanoes known as the Virunga Volcanoes runs through a western section of the Rift Valley, forming part of the border between Uganda, Democratic Republic of Congo and Rwanda. These spectacular mountains and the nearby Bwindi Impenetrable National Park in Uganda are the last refuges of the most endangered of the gorilla subspecies, the mountain gorilla.
Mountain gorillas are as shy as they are strong. But when threatened, they can be aggressive. They beat their chests and let out angry grunts and roars. Group leaders will charge at the threat. Mothers will fight to the death to protect their young.
Mountain gorillas live in groups of up to 30. The group or family is led by a silverback. These males are called silverbacks because of the silver stripe they develop on their backs when they mature. The oldest males of the group are at least 12 years old. These troops also include several younger males, adult and juvenile females, and infants.
In addition to providing protection to group members, silverbacks maintain order and decide all activities within their troop. They schedule feeding trips, resting time, and travel. They also father the majority of the young in the group.
Female mountain gorillas can produce young ones beginning at age 10. They carry one or two babies at a time and give birth after 8.5-month gestation period. In general, they will bear between two and six offspring in a lifetime.
The gorilla is massive, with a short, thick trunk and broad chest and shoulders. Its eyes and ears are dwarfed by its large head and hairless, shiny black muzzle. Older males develop a crown of muscle and hair that makes the head look even longer. The arms are longer than the stubby legs. The fully adult male mountain gorilla is twice as large as the female.
The most serious threat to gorillas is habitat loss. The rich volcanic soil of the Virunga is as highly valued as farming land. In Rwanda, Uganda and Congo, a regional conservation program stressing the importance of maintaining the virgin forest watershed and the need to habituate some groups of gorillas for tourist visits has helped ease encroachment.
The gorilla is shy and retiring rather than ferocious and treacherous. It usually seeks no trouble unless harassed but will valiantly defend its family group if threatened. Family groups are close-knit and may have up to 30 members, but even if smaller, the group usually consists of at least one older male, one or more females and a few juveniles. Because gorillas are nomadic, they build new nests each day at dusk, constructing them of bent branches in a tree or of grasses on the ground.
A group’s hierarchy, ritualized behavior and bluff charges between males prevent conflict among and between groups. Gorillas scream, grab foliage and stuff it in their mouths, stand erect on their hind legs, tear up and throw plants, drum on the chest with hands or fists, stamp their feet, strike the ground with the palms of their hands and gallop in a mock attack on all fours.
Animals of this size need a lot of food, and the vegetarian gorilla is no exception. Although they eat a variety of plants, favorites include wild celery, bamboo, thistles, stinging nettles, bedstraw and certain fruit. These plants seem to provide sufficient moisture so that gorillas do not need water.
Mountain gorillas have a slow rate of reproduction. Females give birth for the first time at about age 10 and will have more offspring every three or four years. A male begins to breed between 12 and 15 years, when he is in charge of his own group. Able to conceive for only about three days each month, the female produces a single young.
Newborn gorillas are weak and tiny, weighing in at about 4 pounds. Their movements are as awkward as those of human infants, but their development is roughly twice as fast. At 3 or 4 months, the gorilla infant can sit upright and can stand with support soon after. It suckles regularly for about a year and is gradually weaned at about 31/2 years, when it becomes more independent.
The gorilla’s only known enemies are leopards and humans. Crocodiles are potentially dangerous to lowland gorillas. In western Africa, gorillas are commonly hunted for meat or in retaliation for crop raiding, but in eastern Africa they have been the victims of snares and traps set for antelope and other animals. Poachers have also destroyed entire family groups in their attempts to capture infant gorillas for zoos, while others are killed to sell their heads and hands as trophies.