Eastern Lowland Gorilla (Grauer’s Gorilla): Size, Habitat, Diet & More

The eastern lowland gorilla, also known scientifically as Grauer’s gorilla (Gorilla beringei graueri), is the largest primate on Earth and a critically endangered subspecies native to the Democratic Republic of Congo (DRC).

Anyone researching gorilla trekking in the DRC or comparing it to mountain gorilla trekking in Uganda and Rwanda will want to understand this remarkable, lesser-known gorilla subspecies first.

Renowned for its stocky build, complex social behavior, and herbivorous diet, this majestic great ape faces severe threats from habitat loss, poaching, and civil unrest.

In 2025, conservation efforts — including the historic rewilding of four females by the Gorilla Rehabilitation and Conservation Education (GRACE) Center — offer real hope for its survival.

Eastern Lowland Gorilla

What Is the Eastern Lowland Gorilla?

The eastern lowland gorilla is one of two subspecies of the eastern gorilla (Gorilla beringei), alongside the mountain gorilla (Gorilla beringei beringei) trekked by travelers in Uganda’s Bwindi Impenetrable National Park and Rwanda’s Volcanoes National Park.

Named after Austrian zoologist Rudolf Grauer, it’s the largest gorilla subspecies and the largest living primate, distinguished by its stocky body, large hands, short muzzle, and jet-black fur.

Found exclusively in the lowland tropical rainforest of eastern DRC, it plays a vital ecological role, dispersing seeds and pruning vegetation throughout its range.

With a population estimated at 3,800–6,800 in 2021, down from roughly 17,000 in the 1990s, its critically endangered status underscores just how urgent conservation efforts have become.

Physical Characteristics of the Eastern Lowland Gorilla

Eastern Lowland Gorilla Body Features

The eastern lowland gorilla is distinguished by its stocky body, large hands, and broad chest, with a shorter muzzle than western gorillas that gives it a notably powerful jaw structure.

Its coat is typically short and jet black, though older males — silverbacks — develop the striking silver-grey saddle of hair across their backs that gives the term its name.

They possess thick limbs and heavily muscled shoulders adapted for knuckle-walking and climbing, along with a large skull featuring a pronounced sagittal crest that anchors strong jaw muscles.

This subspecies is built for strength rather than speed, allowing it to move through the dense lowland rainforest of the DRC with real dominance and endurance.

Eastern Lowland Gorilla Size

The eastern lowland gorilla is the largest primate on Earth, with males weighing 331–461 lbs (150–209 kg) and females 168–198 lbs (76–90 kg). It’s heavier than the mountain gorilla (males: 267–430 lbs, females: 150–200 lbs) thanks to its especially stocky build.

The western lowland gorilla is lighter still (males: 300–430 lbs, females: 150–180 lbs), while the Cross River gorilla is similar but slightly smaller (males: 300–400 lbs, females: 140–180 lbs).

The eastern lowland gorilla’s size reflects its adaptation to the DRC’s lowland forest, where robust strength is essential for foraging.

Eastern Lowland Gorilla Height

The eastern lowland gorilla is the tallest of all gorilla subspecies, with adult males reaching 1.7–1.85 meters (5 ft 7 in – 6 ft 1 in) when standing upright, and females averaging around 1.6 meters (5 ft 3 in).

By comparison, western lowland gorillas average 1.6–1.75 meters for males, and mountain gorillas — despite being more robust — are similarly shorter, averaging 1.6–1.75 meters for males as well.

The eastern lowland gorilla’s greater height, combined with its stocky build, makes it the most physically imposing gorilla subspecies of all.

Eastern Lowland Gorilla Strength

The eastern lowland gorilla is incredibly strong, with adult males capable of lifting or carrying loads up to ten times their body weight. Their muscular arms, broad shoulders, and powerful grip let them break apart thick vegetation, strip bark, and climb with ease.

This immense strength matters for dominance displays, defending the group, and foraging in dense rainforest — and while peaceful by nature, it makes them one of the most formidable animals in the entire animal kingdom.

Eastern Lowland Gorilla Habitat and Distribution

The eastern lowland gorilla inhabits the lowland tropical rainforest and montane forest of eastern DRC, with the widest altitudinal range of any gorilla subspecies. Key habitats include:

Kahuzi-Biega National Park — home to the largest protected population, with dense primary forest and Cyperus swamps.
Maiko National Park — hosts smaller populations across lowland forest.
Tayna Gorilla Reserve, Usala Forest, and Itombwe Massif — support fragmented populations in unprotected areas.
Mt. Tshiaberimu (Virunga National Park) — a small, isolated population of just 12 individuals (as of 2024) confined to a 77 sq km forest patch.

Their range has shrunk to just 13% of its historical 21,000 sq km — from 8,100 sq miles to 4,600 sq miles over 50 years — driven by deforestation and human encroachment.

Eastern Lowland Gorilla Diet and Feeding Habits

The eastern lowland gorilla is primarily herbivorous, consuming up to 18 kg of vegetation daily, supplemented occasionally by insects. Their diet includes:

Plants — fruit, leaves, shoots, stems, and bark, with a preference for regenerating vegetation in abandoned fields.
Insects — ants, termites, and other small insects form a minor part of the diet.
Ecological role — by dispersing seeds and pruning plants, eastern lowland gorillas enhance forest biodiversity and open sunlight gaps that support new plant growth.

Their moisture-rich diet reduces the need for drinking water, and while they generally avoid banana fruit, they may eat banana pith when it’s available.

Eastern Lowland Gorilla Lifespan

The eastern lowland gorilla has an average lifespan of 35 to 40 years in the wild, though individuals in captivity can live slightly longer, sometimes reaching 50 years with proper care. Longevity depends on habitat quality, food availability, and protection from threats like poaching and disease. In stable environments, they can thrive for decades, with silverbacks leading and protecting their groups through most of their adult life, ensuring the ongoing survival and stability of the troop.

Social Behavior and Group Structure

Eastern lowland gorillas are highly social, living in troops of 2 to 30 individuals led by a dominant silverback.

Troop dynamics: Groups typically comprise one or two silverbacks, females, and their offspring — some groups even include two mature males, unlike many other primates.

Silverback role: The alpha male protects the group, leads foraging, and chooses nesting sites.

Social bonds: Grooming, play, and vocalizations — grunts, hoots — strengthen family bonds within the troop.

Female mobility: Females may transfer to other troops or join lone silverbacks at maturity, while males may form new groups or challenge for leadership as they mature.

Reproduction and Parenting

Reproduction in eastern lowland gorillas is slow, which contributes directly to their vulnerability as a species.

Gestation lasts 8.5 to 9 months, similar to humans, with females giving birth to a single infant (or, rarely, twins) every 4 to 6 years.

Infant care: Newborns weigh around 2 kg (4.4 lbs), are carried for the first 3 months, and breastfeed for up to 3 years. Infants sleep in their mother’s nest and ride on her back as they grow.

Maturity: Females reach sexual maturity at around 8 years, males at 9, though males typically don’t reproduce as full silverbacks until 12–15 years of age.

Parenting: Mothers provide primary care, while silverbacks play with and actively protect the group’s offspring.

Eastern Lowland Gorilla Population and Conservation Status

The eastern lowland gorilla is critically endangered, with a population estimated at 3,800–6,800 as of 2021 — down more than 50% from roughly 17,000 in the 1990s.

Historical decline: Numbers fell from 16,900 in 1996 to 3,800 by 2015, with a 77% drop in some areas. A 2021 survey suggests the population may be as high as 6,800, indicating a slower decline than previously feared.

Mt. Tshiaberimu: A tiny population of just 12 individuals (as of 2024) faces genuine extinction risk without reinforcement.

Captivity: Only one female lives in captivity, at Antwerp Zoo in Belgium, as the subspecies adapts poorly to zoo environments.

Why Is the Eastern Lowland Gorilla Endangered?

The eastern lowland gorilla is endangered primarily due to habitat loss, poaching, and the effects of civil conflict across its native range in the DRC. Expanding agriculture, logging, and mining have destroyed large areas of rainforest habitat, while poachers hunt gorillas for bushmeat and sometimes capture infants for the illegal wildlife trade — often killing protective adults in the process.

Armed conflict in the region compounds these threats further, disrupting conservation work and forcing displaced people into gorilla habitat. As a result, the population has declined by over 50% in recent decades, making urgent, well-funded protection genuinely vital.

eastern lowland gorilla size

Conservation Efforts in 2026

GRACE Center: The Gorilla Rehabilitation and Conservation Education (GRACE) Center, near the Tayna Nature Reserve, is the only sanctuary dedicated to Grauer’s gorillas. In May 2025, GRACE reintroduced four rehabilitated females — Isangi, Lulingu, Mapendo, and Ndjingala — to Mt. Tshiaberimu, boosting the population there from 8 to 12 individuals.

Rewilding process: Orphans rescued from the wildlife trade between 2010 and 2016 were rehabilitated in a 39-acre forest enclosure, learning foraging, nest-building, and social skills. Released in December 2024, they successfully integrated with a wild silverback named Mwasa, showing both mating behavior and dietary adaptation, including eating bamboo.

Virunga National Park hosts the Mt. Tshiaberimu population, protected through ranger patrols and community programs covering all 12 gorillas.

Kahuzi-Biega National Park supports the largest remaining population, with gorilla trekking permits (around $400 each) directly funding conservation work.

Community engagement: GRACE has educated roughly 27,000 local residents through World Gorilla Day events and school programs, fostering genuinely community-led conservation.

WWF and partners: The World Wildlife Fund and the Gorilla Organization fund ranger training, anti-poaching patrols, and habitat restoration, while Gorilla Doctors provide non-invasive health monitoring to keep rewilded gorillas healthy long-term.

Gorilla Trekking in the DRC: What to Expect

Gorilla trekking offers a genuinely unique way to support eastern lowland gorilla conservation directly through your visit.

Locations: Kahuzi-Biega and Maiko National Parks are the primary trekking sites for this subspecies.
Cost: Around $400 per permit, allowing a one-hour visit with a habituated troop.
Best time: The dry season (January–February, May–September) avoids muddy, difficult trails.
Requirements: Hiking boots, a hat, sunscreen, insect repellent, binoculars, and a valid trekking permit.
Experience: Treks last 30 minutes to 2 hours, guided by experienced rangers, offering close encounters with silverbacks and their troops.

Because Kahuzi-Biega and Virunga sit close to the Rwandan border, many travelers combine eastern lowland gorilla trekking in the DRC with mountain gorilla trekking in Rwanda’s Volcanoes National Park on a single cross-border itinerary — our 5 Days Rwanda Congo Gorilla Safari is built specifically around that combination, letting you see both gorilla subspecies on one trip.

How Eastern Lowland Gorilla Trekking Compares to Mountain Gorilla Trekking

Travelers researching Grauer’s gorilla naturally compare it to the better-known mountain gorilla trekking safaris in Uganda and Rwanda.

Mountain gorillas live in cooler, high-altitude forest across Volcanoes National Park in Rwanda and Bwindi Impenetrable National Park in Uganda, with a larger, more stable population and significantly more developed trekking infrastructure — reflected in higher permit costs but smoother logistics overall.

Eastern lowland gorilla trekking in the DRC, by contrast, is rarer, more affordable, and less crowded, but comes with more variable security conditions given ongoing regional instability.

For a full breakdown of what to expect on the more established Rwanda side, see our guide to gorilla trekking in Rwanda, or our detailed comparison of gorilla trekking in Rwanda vs Uganda if you’re deciding where to base a wider East Africa gorilla safari.

Future Outlook for Eastern Lowland Gorillas (2026–2030)

2025–2026: Rewilding efforts, like GRACE’s work at Mt. Tshiaberimu, aim to bolster small, isolated populations, with continued monitoring by Gorilla Doctors supporting long-term health stability.

GRACE plans to expand its education programs to 50,000 local residents by 2026, strengthening community anti-poaching support, while projected 10% growth in trekking tourism helps fund park security.

2027–2030: WWF and the Gorilla Organization aim to restore 10% of lost habitat through reforestation, targeting population stabilization at 7,000–8,000 individuals alongside stronger anti-poaching enforcement and mining bans. Global support — including carbon credit programs and ethical sourcing initiatives like coltan-free electronics — could help further reduce habitat destruction. Civil unrest, illegal mining, and climate-driven threats like wildfires remain significant hurdles to all of this.

How to Support Eastern Lowland Gorilla Conservation

Donate — support GRACE, WWF, or the Gorilla Organization to fund rehabilitation and ranger patrols; even modest monthly donations to organizations like the Gorilla Organization help fund habitat protection.
Adopt a gorilla — WWF’s adoption program channels ongoing funding directly into conservation projects.
Go gorilla trekking — book through a reputable operator to help fund park maintenance and ranger salaries directly. If you’re planning a Rwanda-based trip alongside a DRC extension, our guides to Rwanda’s national parks, the best time to visit Rwanda, and our full range of Rwanda safari itineraries can help you plan the logistics.
Raise awareness — share GRACE’s rewilding success on social media or take part in World Gorilla Day events.
Make ethical consumer choices — choosing coltan-free electronics helps reduce mining pressure on gorilla habitat.

Interested in combining eastern lowland gorilla trekking in the DRC with a wider Rwanda gorilla safari? A Kigali to Volcanoes safari or 2 Days Rwanda Gorilla Trekking Safari both pair naturally with a Congo extension. Get in touch with our safari planners to build an itinerary around your travel dates, or learn more about how Hail Tours Uganda plans cross-border gorilla safaris across Uganda, Rwanda, and the DRC.