Mountain Gorilla
The mountain gorilla is a subspecies of the eastern gorilla that lives in only two small areas of central Africa: the Virunga volcanoes, shared by Rwanda, Uganda and the Democratic Republic of the Congo, and Bwindi Impenetrable National Park in southwestern Uganda, which continues into Congo's small Sarambwe reserve. These great apes live between about 1,400 and 3,800 meters above sea level, in cloud forest, bamboo and mountain vegetation where nights can drop close to freezing. Their long, thick fur keeps them warm in the cold and misty highlands. Families usually number around ten gorillas, though some have more than thirty, and they are led by an adult male called a silverback for the saddle of silver hair on his back. Mountain gorillas spend much of the day eating leaves, stems, pith and shoots, and each evening every adult builds a fresh nest to sleep in. After falling to about 240 animals in the Virungas in 1981, the subspecies has climbed past 1,000 individuals thanks to rangers, veterinarians and carefully managed gorilla tourism, one of the few real recoveries among the great apes.
What is a mountain gorilla? Scientific name and relatives
The mountain gorilla is one of the four kinds of gorilla alive today and one of the rarest great apes on Earth. Its scientific name is Gorilla beringei beringei. The word beringei honors Robert von Beringe, a German officer who shot two of these gorillas on Mount Sabyinyo in 1902, the first time scientists were able to examine the animal. Gorillas are divided into two species. The western gorilla, Gorilla gorilla, includes the western lowland gorilla and the Cross River gorilla. The eastern gorilla, Gorilla beringei, includes the mountain gorilla and Grauer's gorilla, also called the eastern lowland gorilla, which lives in the lowland and hill forests of eastern Congo. In some places the mountain gorilla is also called the highland gorilla, a name that simply points to the cold mountain forests where it lives. Compared with lowland gorillas, mountain gorillas have longer and thicker black fur, which helps them cope with chilly nights high on the volcanoes. The gorillas of Bwindi and those of the Virunga volcanoes have been genetically separated for several thousand years, and some researchers think they could be treated as different groups, but the IUCN still counts them as a single subspecies.
What is a silverback gorilla?
A silverback is an adult male gorilla, usually around 12 years old or more, whose back has turned silver gray. As males mature, the hair on their back becomes short and pale, forming a saddle that stands out against the rest of the black coat. At the same time they grow long canine teeth, a broad chest and a crest of bone on top of the skull that anchors huge jaw muscles. Younger males, between about 8 and 12 years old, are known as blackbacks. Every gorilla species has silverbacks, but the picture most people have in mind, a huge male sitting in a misty bamboo forest, usually comes from the Virungas and Bwindi. The dominant silverback leads his family. He decides when the group moves, where it feeds and where it spends the night, and he steps in to calm fights between females or young gorillas. If danger appears, he stands up, hoots, beats his chest with cupped hands and may charge, a display meant to scare intruders away rather than to hurt them. In the Virunga mountains, about a third of the groups have two or more silverbacks, usually a leader and his sons or brothers, and some very large groups have had up to eight. These extra males help defend the family against rival males from outside.
How big is a mountain gorilla? Size, weight and the largest silverbacks
Mountain gorillas are among the largest primates in the world, and males weigh about twice as much as females. An adult silverback usually weighs about 140 to 200 kilograms, with an average close to 155 kilograms, and a few wild males have been recorded at around 220 kilograms. Standing fully upright, which gorillas rarely do, a male reaches about 1.5 to 1.7 meters, and his arms spread up to about 2.3 meters from fingertip to fingertip, much wider than his height. Adult females weigh around 70 to 100 kilograms and stand about 1.3 meters tall. Most of the time gorillas walk on all fours, resting their weight on the knuckles of their hands, so they look shorter and wider than they really are. Their long fur, thicker than that of lowland gorillas, makes them look even bigger. People often ask which is the largest silverback alive. In Rwanda, Guhonda, a famous silverback of the Sabyinyo group in Volcanoes National Park, has long been described as the biggest male in the Virungas, with a weight usually given as about 220 kilograms. That figure is an estimate, since wild dominant males are almost never weighed, and the heaviest wild gorilla on record was a western gorilla from Cameroon, not a mountain gorilla.
Where do mountain gorillas live?
Mountain gorillas live in only two places, both in the highlands where Rwanda, Uganda and the Democratic Republic of the Congo meet. The first is the Virunga massif, a chain of volcanoes protected by three neighboring parks: Volcanoes National Park in Rwanda, Mgahinga Gorilla National Park in Uganda and the Mikeno sector of Virunga National Park in Congo. The census carried out in 2015 and 2016 counted at least 604 gorillas there. The second is Bwindi Impenetrable National Park in southwestern Uganda, together with the small Sarambwe reserve just across the border in Congo, where the 2018 census counted 459 gorillas. The two areas lie only a few dozen kilometers apart, but farmland and villages separate them, so the gorillas cannot move from one to the other. According to the IUCN, mountain gorillas live between about 1,400 and 3,800 meters above sea level. In the Virungas they move through bamboo forest, cloud forest of hagenia and hypericum trees, and open slopes covered in giant herbs, where nights are cold and fog is common all year. Bwindi is lower and warmer, a steep maze of rainforest, hills and ravines that gave the park its impenetrable name.
What do mountain gorillas eat?
Mountain gorillas are mainly plant eaters, and finding food fills a large part of their day. In the Virungas they feed on the leaves, stems, pith and roots of a few dozen kinds of plants, such as wild celery, thistles, nettles and bedstraw, and they eat young bamboo shoots when the bamboo sprouts in the rainy season. They also peel bark, chew rotting wood, lick soil and now and then eat ants and other small insects. Because leaves and stems give little energy, they need large amounts of them. A year long study in Bwindi found that adult males ate about 19 kilograms of food a day and adult females about 15 kilograms. Fruit matters more than people often think. The Virunga gorillas, living high on the volcanoes, are almost entirely leaf eaters, but the Bwindi gorillas eat fruit whenever the trees offer it. On average they spend about 15 percent of their feeding time on fruit, and in some months much more, which makes them walk farther each day than their Virunga cousins as they check fruiting trees. Mountain gorillas rarely drink water, since the juicy plants they eat give them almost all the moisture they need.
How do mountain gorilla families live?
Mountain gorillas live in stable family groups, usually of around ten animals, although sizes range from just two or three to more than thirty. In the Virungas, a few groups studied by the Dian Fossey Gorilla Fund grew to between 25 and 65 gorillas, with several silverbacks living together. A typical group has one dominant silverback, several adult females, their young and sometimes a few blackbacks or younger silverbacks. Unlike in many other mammals, it is mostly the females who change families. When they reach adulthood, many young females leave the group they were born in and join another group or a lone silverback, and some move more than once in their lives. Young males either stay and wait for a chance to lead, or leave and spend years alone until they can attract females and start a family of their own. The bond between each female and the silverback is the glue that holds the group together, more than friendships among the females. Mothers carry their babies on the chest at first and later on their backs, and infants stay close to them for about three to four years. Grooming, resting side by side and play keep relationships calm inside the group.
Mountain gorilla behavior: nests, chest beating and play
Despite their size, mountain gorillas are calm animals that spend most of the day eating, resting and moving slowly through the forest. Around midday the group usually stops for a long rest, when adults doze and young gorillas play nearby. Each evening, every gorilla older than about three years builds a fresh nest by bending and folding branches, leaves and stems into a kind of mattress. In the Virungas most nests are on the ground, while Bwindi gorillas sleep in trees more often. Infants share their mother's nest until they are old enough to build their own. Chest beating is the most famous gorilla behavior, and both sexes do it, although silverbacks do it most. A study of Virunga silverbacks found that the sound of their chest beats can be heard about a kilometer away and that bigger males produce deeper beats, so the drumming tells rivals and females how large the male is without a fight. Gorillas also communicate with soft belching grunts that mean all is well, barks, screams and loud hoots. Young gorillas are very playful. They chase each other, wrestle, climb and swing on vines, and this play teaches them the social skills they will need as adults.
Dian Fossey and the mountain gorillas
No person is more closely linked to mountain gorillas than Dian Fossey, an American researcher encouraged by the paleontologist Louis Leakey to study great apes in the wild. She began her work in the Congolese part of the Virungas in 1967, but unrest forced her to leave, and in September of that year she founded the Karisoke Research Center in Rwanda, between Mount Karisimbi and Mount Bisoke. Fossey spent years getting gorillas used to her presence by copying their sounds, feeding motions and calm postures, and her patient observations showed the world that gorillas are gentle, social animals, not the monsters of old stories. In 1977 poachers killed Digit, a young silverback she was especially fond of, and his death turned her into a fierce campaigner against poaching. She told her story in the book Gorillas in the Mist, published in 1983 and made into a film in 1988. In December 1985 Fossey was found murdered in her cabin at Karisoke, a crime that was never clearly solved, and she was buried beside Digit in the gorilla cemetery she had built. The Dian Fossey Gorilla Fund still runs Karisoke today, the longest running study of wild gorillas in the world.
Gorilla trekking: how to see mountain gorillas in the wild
Seeing mountain gorillas means walking into the forest with rangers to visit a habituated group, a family that has been slowly used to people over several years. In Rwanda, treks start from Volcanoes National Park, where a permit costs US$1,500 per person. In Uganda, visitors can trek in the four sectors of Bwindi Impenetrable National Park or in Mgahinga Gorilla National Park, where permits cost less than in Rwanda. In Congo, visits to the Mikeno sector of Virunga National Park depend on security and have been suspended for long periods because of armed conflict. Trackers go out early to find each family, and the walk can take from half an hour to several hours over steep, muddy slopes. The rules are strict to protect the gorillas: at most eight visitors per group each day, one hour with the gorillas, a minimum distance of about 7 meters, no visits for people who feel ill, and a minimum age of 15. Since gorillas catch human colds and other respiratory diseases, many parks now ask visitors to wear masks near them. Part of the permit money goes to the villages around the parks, which gives local families a direct reason to protect the forest and the gorillas in it.
Are mountain gorillas endangered?
Yes. The IUCN lists the mountain gorilla as Endangered, in an assessment made in 2018 that moved it down from Critically Endangered, and it counts about 600 mature individuals with an increasing trend. That improvement is one of the rare good news stories among great apes. In 1981 only about 240 gorillas were left in the Virungas. Today the last full counts add up to about 1,060 animals: at least 604 in the Virungas in 2015 and 2016, and 459 in Bwindi and Sarambwe in 2018. A new census of Bwindi began in 2025. The recovery is the result of what experts call extreme conservation: rangers who patrol every day, veterinarians of Gorilla Doctors who remove snares and treat sick gorillas in the forest, close daily monitoring of each family, and tourism money shared with local communities. The danger has not gone away. The gorillas live in two small islands of forest with no room to spread, and crowding in the Virungas has already led to more fights between groups. Human respiratory diseases, snares set for antelopes, and armed conflict in eastern Congo remain serious threats. In 2026 the IUCN Green Status rated the subspecies as Largely Depleted, a reminder that it is still far from the numbers its forests once held.
