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Eastern lowland gorilla. © Eric Baccega / Nature Picture Library

Eastern lowland gorilla. © Eric Baccega / Nature Picture Library

Eastern lowland gorilla

World’s largest ape


The eastern lowland gorilla is the largest of all four gorilla subspecies. It is also known as Grauer’s gorilla, a name that scientists tend to prefer. Its more common name is slightly misleading because it is equally at home at higher altitudes, but its range doesn’t overlap with its close – and more famous – cousin, the mountain gorilla. Both of these great apes are subspecies of eastern gorilla.

Fascinating facts about eastern lowland gorillas

    Name check

    This gorilla’s alternative and scientific names derive from the Austrian zoologist and explorer, Rudolf Grauer, who first recognised it as a separate subspecies. 

    Alpha Romeo

    The biggest silverbacks stand almost two metres tall and can weigh up to 250 kilos – roughly the same as a baby grand piano. 

    Heavy load

    Eastern lowland gorillas have broad hands and feet, with stubby fingers and toes, which help to support their vast bulk when they are upright or knuckle-walking on all fours. 

    Eastern lowland gorilla. Credit: Angelique Todd / Fauna & Flora

    Eastern lowland gorilla. Credit: Angelique Todd / Fauna & Flora

    Short & narrow

    Eastern lowland gorillas have shorter fur and narrower faces than mountain gorillas. 

    United we stand

    Anecdotal observations suggest that – unlike other gorilla subspecies – if a group feels threatened, the whole family will stand its ground instead of fleeing. 

Eastern lowland gorilla family life 

Eastern lowland gorillas are highly sociable primates. They live in family groups comprising up to 30 individuals. Every gorilla family includes an alpha male, known as a silverback, and several adult females. In larger groups, younger adult males are also tolerated. The world’s largest gorilla is a gentle giant. They live together harmoniously, avoid confrontation with other groups of gorillas and show aggression only when they feel threatened by intruders. Gorillas spend more time on the ground than most other primates, where their sheer size provides protection from predators.  

Baby eastern lowland gorilla. ©  Christophe Courteau / Nature Picture Library

Baby eastern lowland gorilla. ©  Christophe Courteau / Nature Picture Library

A baby eastern lowland gorilla safe in the protective arms of a family member.

How do eastern lowland gorillas communicate? 

Eastern lowland gorillas females and young are generally quiet, but the silverback advertises his presence with a series of loud hoots and chest-beating, a sound that carries over long distances. When alarmed, the alpha male also emits a range of barks, roars or screams.

What do eastern lowland gorillas eat? 

The diet of eastern lowland gorillas is almost exclusively vegetarian. They feed on a wide variety of herbs, leaves, bark, vines, bamboo and fruit, but will also eat insects. They favour clearings and other disturbed areas of forest where there is a dense tangle of new growth. 

Where do eastern lowland gorillas live? 

Eastern lowland gorillas are found only in the Democratic Republic of Congo (DRC). They are confined to primary tropical forest in the east of the country. Their main strongholds include Kahuzi-Biega and Maiko National Parks, but their range extends across unprotected areas of forest. An estimated three-quarters of eastern lowland gorilla habitat falls outside existing parks and nature reserves. 

Silverback Eastern lowland gorilla. © Karl Ammann / Nature Picture Library

Silverback Eastern lowland gorilla. © Karl Ammann / Nature Picture Library

A silverback male eastern lowland gorilla knuckle-walking through typical forest habitat.

How many eastern lowland gorillas are left? 

A 2016 report by Fauna & Flora, the Wildlife Conservation Society and other partners documented an alarming drop in eastern lowland gorilla numbers, from an estimated 17,000 in 1995 to just 3,800 individuals. A more recent follow-up study led to this estimate being revised upwards to 6,800, but this is still less than half the number recorded a quarter of a century earlier. The world’s largest gorilla subspecies is now classified as Critically Endangered on the IUCN Red List of Threatened Species.

Why are eastern lowland gorillas endangered? 

Eastern lowland gorillas are severely threatened by human activities, the most damaging of which are hunting for meat, deforestation and encroachment. 


The dramatic decline in eastern lowland gorilla numbers has been driven primarily by hunting. There is high and increasing demand for wild meat from a growing human population that has few alternative, affordable proteins. Rebel militia groups and increasing numbers of artisanal miners add to the hunting pressure. 

Habitat destruction 

Crucial tracts of eastern lowland gorilla habitat are being lost to agricultural conversion, timber extraction, livestock ranching, artisanal mining and infrastructure development. Barely a quarter of the forest landscapes with the eastern lowland gorilla’s range benefit from legal protection. Oil and gas exploration concessions pose an additional threat.

Agriculture beside Kahuzi-Biega National Park. © Thalia Liokatis / Fauna & Flora

Agriculture beside Kahuzi-Biega National Park. © Thalia Liokatis / Fauna & Flora

Beyond national park boundaries, much of the forested habitat of eastern lowland gorillas is being lost to agricultural conversion.

Human disturbance 

Eastern lowland gorillas have the misfortune to live in a conflict zone. The long-term presence of armed groups has had a destabilising impact on their population above and beyond the poaching threat. Human disturbance affects their behaviour, feeding patterns and social interaction. The permanent presence of people employed by extractive industries in the forest has also aggravated these threats in recent years. 


Gorillas share almost 98% of their DNA with humans. As a result, they are susceptible to the same diseases, but they lack the natural resistance to human-borne infections, meaning that these can be potentially fatal. This poses a constant danger to habituated eastern lowland gorilla groups that are exposed to tourists, and to gorillas that otherwise come into close contact with people. 

How can we help save eastern lowland gorillas? 

Since 2012, Fauna & Flora has worked with local communities and authorities to conserve eastern lowland gorillas and their habitat in community forest areas outside the national parks. 

Today, Fauna & Flora is supporting three community reserves that are home to eastern lowland gorillas. We help to build local capacity, as well as training and equipping community rangers. 

We have also been helping the reserves to conduct monthly bio-monitoring patrols that record the presence of eastern lowland gorilla groups and other threatened species such as chimpanzee, okapi and Congo peafowl. While monitoring, rangers also remove snares that can be life-threatening for these critically endangered apes. 

Save the world’s greatest ape

Together, we can bring eastern lowland gorillas back from the brink. 

Please help us to reverse their dramatic decline.

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