Mountain Gorillas vs Eastern Lowland Gorillas

The Difference Between Mountain Gorillas and Eastern Lowland Gorillas: A Detailed Guide

Gorillas are among the most fascinating creatures on Earth, captivating both scientists and tourists alike with their intelligence, social behavior, and resemblance to humans. Of the two main species, the western gorilla and the eastern gorilla—the eastern species is further divided into two subspecies: the Mountain Gorilla (Gorilla beringei beringei) and the Eastern Lowland Gorilla (Gorilla beringei graueri), also known as Grauer’s gorilla.

Though they share many similarities, mountain gorillas and eastern lowland gorillas differ significantly in their habitat, physical features, diet, behavior, and conservation status. This article provides a comprehensive look at the key differences between these two incredible subspecies.

1. Habitat and Range

Mountain Gorillas

Mountain gorillas inhabit the high-altitude forests of central and eastern Africa. Specifically, they are found in:

  • The Virunga Mountain Range, which spans Rwanda (Volcanoes National Park), Uganda (Mgahinga Gorilla National Park), and the Democratic Republic of Congo (Virunga National Park)

  • Bwindi Impenetrable National Park in southwestern Uganda

These areas are typically located at elevations between 2,200 to 4,300 meters (7,200 to 14,100 feet) above sea level. The climate is cool and moist with dense montane forests and thick undergrowth.

Eastern Lowland Gorillas

Eastern lowland gorillas live in the lowland tropical forests of the eastern Democratic Republic of Congo, primarily in:

  • Kahuzi-Biéga National Park

  • Maiko National Park

  • Surrounding areas including the Itombwe Massif and Tayna regions

They prefer lower elevations—between 600 and 2,900 meters (2,000 to 9,500 feet)—in dense, humid rainforests.

2. Physical Appearance

Mountain Gorillas

  • Fur: Have longer and thicker fur than their lowland counterparts. This helps them stay warm in cold mountain temperatures.

  • Build: Stocky and muscular with shorter arms compared to body size.

  • Color: Adults often have darker, almost black fur. Males develop a silvery patch on their backs as they age, known as a silverback.

  • Facial features: More pronounced brows and a shorter face.

Eastern Lowland Gorillas

  • Fur: Shorter and finer fur adapted to the warmer climate.

  • Size: Larger than mountain gorillas; males can weigh up to 250 kilograms (550 lbs) and stand up to 1.85 meters (6 feet) tall.

  • Build: Broad chest, massive hands, and more elongated limbs.

  • Color: Coat tends to be dark brown to black with a slight grayish tint.

3. Diet and Foraging Behavior

Mountain Gorillas

  • Diet: Primarily folivorous (leaf eaters). They consume a variety of leaves, shoots, stems, bark, and occasionally fruits when available.

  • Food Sources: Due to their habitat, fruit is less abundant, so they rely heavily on fibrous vegetation.

  • Foraging Range: Smaller home ranges since their food sources are generally plentiful and closely packed.

Eastern Lowland Gorillas

  • Diet: More frugivorous (fruit eaters) than mountain gorillas. Their diet includes fruits, leaves, stems, bark, and seeds.

  • Food Sources: Their rainforest habitat provides a richer supply of fruits, especially during the rainy season.

  • Foraging Range: Tend to travel longer distances in search of fruiting trees.

4. Behavior and Social Structure

Mountain Gorillas

  • Live in groups ranging from 5 to 30 individuals, usually led by one dominant silverback male.

  • Highly cohesive social units with strong family bonds.

  • Groups are more stable, and infighting or challenges to the dominant male are less frequent.

  • Less arboreal; spend most of their time on the ground due to their large size and forest type.

Eastern Lowland Gorillas

  • Also live in groups, though sometimes more fluid in composition.

  • Social groups can be larger, sometimes exceeding 30 individuals.

  • Slightly more arboreal, especially juveniles and females, as their environment allows easier tree access.

  • Groups may split or merge based on food availability and social dynamics.

5. Population and Conservation Status

Mountain Gorillas

  • Estimated population: Around 1,063 individuals (as of 2023)

  • Conservation Status: Endangered (IUCN Red List)

  • Main threats: Habitat loss, human encroachment, disease (especially respiratory diseases from human contact), and poaching (though direct poaching is rare today).

  • Conservation efforts: Robust conservation programs in Rwanda, Uganda, and DRC have led to a slight increase in numbers. Gorilla trekking tourism has also contributed positively to their protection.

Eastern Lowland Gorillas

  • Estimated population: Fewer than 3,800 individuals (drastically down from over 17,000 in the mid-1990s)

  • Conservation Status: Critically Endangered

  • Main threats: Civil conflict in eastern DRC, illegal mining, habitat destruction, bushmeat hunting, and limited conservation infrastructure.

  • Conservation challenges: Lack of political stability and ongoing violence make conservation efforts more difficult compared to mountain gorilla regions.

6. Tourism and Human Interaction

Mountain Gorillas

  • A major focus of eco-tourism in Rwanda and Uganda.

  • Well-regulated tourism with permits and strict guidelines to prevent disease transmission and minimize stress to the animals.

  • Gorilla trekking generates significant revenue, a portion of which supports local communities and conservation.

Eastern Lowland Gorillas

  • Less accessible to tourists due to the volatile security situation in the DRC.

  • Some trekking is possible in Kahuzi-Biéga National Park, but it is far less developed compared to mountain gorilla tourism.

  • Increased security and investment are needed for lowland gorilla tourism to thrive.

In conclusion While mountain gorillas and eastern lowland gorillas both belong to the same species group, their differences are shaped by their unique environments. Mountain gorillas are adapted to cool, mountainous regions and have thicker fur and a largely leafy diet. Eastern lowland gorillas, by contrast, thrive in tropical rainforests with access to a wider variety of fruits and have a more robust build with finer fur.

Understanding these differences is not only important for scientific and educational purposes but also crucial for designing effective conservation strategies tailored to each subspecies. As we continue to learn more about these incredible primates, their protection must remain a global priority.