Gorilla beringei graueri

The eastern lowland gorilla is the largest of all gorilla subspecies. It has an intimidating size, making it the biggest of all primates in the world.

Its scientific name is in honor of the Austrian scientist Rudolf Grauer, who first identified this subspecies in the early twentieth century.

Order: Primates
Family: Hominidae
Genre: Gorilla
Species: Gorilla beringei

Description

The anatomy of the eastern lowland gorilla (Gorilla beringei graueri) is robust and big. There is sexual dimorphism as males are larger and heavier than females; on average, an adult male height is 1.69 meters and weighs 163 kilograms, while adult females are about 1.60 meters heigh and weight little more than 81 kg. The largest eastern lowland gorillas are in zoos, and they can reach more than 250 kilograms.

They have a strong skeleton with a big skull compared to the size of the rest of their body, a short snout and a jawbone with teeth. Their arms are long and very developed, longer in males than in females. Their thumbs are longer than the rest of the fingers. Like all gorillas, they walk relaying their weight on their knuckles.

The skin of all gorillas is thick, and the eastern lowland gorilla is no exception. They have a deep layer called the dermis and an outer layer, the epidermis, besides a layer of fat that help them to keep their body temperature stable. Their dark fur coat is shorter than the mountain gorilla, and the hair is absent in the face, hands, feet, and ears.

It has an intimidating size, making it the biggest of all primates in the world.

Information about Eastern lowland gorilla.

Eastern lowland gorilla in captivity. / Photo taken by Aglarech.

Habitat and distribution

The distribution range of eastern lowland gorilla is small, it covers only the eastern part of the Democratic Republic of Congo, with populations in the Maiko National Park, Kahuzi-Biega National Park, the Tayna Gorilla Reserve and Itombwe Mountains region.

This subspecies inhabits mountain tropical forests and lowland tropical forests, although it is capable of living in marshlands and areas with less dense vegetation, as long as they are plants of the genus Cyperus.

Feeding habits

It is a subspecies mainly herbivorous that feeds on leaves, fruits, stems and bark from at least 104 species of plants. Occasionally they add to their diet ants, termites, and some other small insects. They rarely drink water directly from a source, as they get water from the plants they eat.

Like other gorillas, adults can consume up to 18 kilograms of food per day, a significant amount for a human but just enough to allow this animal to maintain its size and health. Thanks to their strength, they can break tough, fibrous plants or tear banana trees to reach the center.

Behavior

The eastern lowland gorilla social structure is organized in family groups with a dominant male, the “silverback”, several females and their offspring. Typically, these groups are formed with 2 to 30 members. It is very rare, but in some cases, there are two leaders.

The dominant male has a privileged position and at the same time a great responsibility. He makes the important decisions as the resting and feeding places; he has access to more food than the other and mates with the sexually mature females. However, he should be alert to threats, and defend his troop from intruders.

Gorillas are not aggressive or territorial. Quite the reverse, they are usually gentle creatures. They spend their day resting, feeding and socializing, but they spend more of their time in feeding-related activities. They rest on nests built with branches and leaves in trees or on the ground.

Reproduction

They are polygamous; therefore males breed with several females of their group throughout his life. Females reach sexual maturity earlier than males, and they often give birth to one offspring per delivery after a gestation period of about 8.5 months.

While the mother takes care and feeds its young with dedication, the “silverback” males also do their part to protect them both. The infants usually sleep in the same nest of their mothers until they are about three years old, and they gradually become independent. Upon reaching sexual maturity, both genders separate from their birth group and create a new group or adhere to another.

Threats and conservation

The Eastern lowland gorilla is endangered (EN).

The Eastern lowland gorilla (Gorilla beringei graueri) is endangered (EN), according to the Red List of the International Union for Conservation of Nature. Records indicate that during the last 20 or 30 years, its population has declined dramatically: in the 1990s there were about 17,000 individuals, but it is likely that this figure was reduced by 50 percent now.

The main dangers of this subspecies are poaching and the trade of its parts, loss, and fragmentation of its habitat, mining (which attracts poachers and promotes social unrest among people in the region) and the armed conflicts that disturb the Democratic Republic of Congo. War is a major problem because it restricts law enforcement and deters the aiming of resources to the conservation of gorillas.

There are some conservation efforts made by international organizations that focus on creating and expanding protected areas and monitor the existing areas where these primates live to reduce the impact of poaching, habitat loss and war.