Eastern Lowland Gorilla

The eastern lowland gorilla is a subspecies of eastern gorilla endemic to the mountainous forests of eastern Democratic Republic of the Congo. Important populations of this gorilla live in the Kahuzi-Biega and Maiko National Parks and their adjacent forests, the Tayna Gorilla Reserve, the Usala forest and on the Itombwe Massif.

It is the largest of the four gorilla subspecies. It has jet black coats like the mountain gorilla (Gorilla beringei beringei), although the hair is shorter on the head and body. The male's coat, like that of other gorillas, greys as the animal matures, resulting in the designation "silverback".

There are far fewer eastern lowland gorillas compared to western lowland gorillas. According to a 2004 report there were only about 5,000 eastern lowland gorillas in the wild, down to fewer than 3,800 in 2016, compared to over 100,000 western lowland gorillas.

Eastern lowland gorillas are highly sociable and very peaceful, living in groups of two to over 30. A group usually consists of one silverback, several females and their offspring. Silverbacks are strong and each group has one dominant leader (see alpha male). These males protect their group from danger. Young silverback males will slowly begin to leave their natal group when they reach maturity, and will then attempt to attract females to form their own group.

Relatively little is known about the social behaviour, history and ecology of eastern lowland gorillas, partly because of civil war in the Democratic Republic of the Congo. However, some aspects of social behaviour have been studied. For example, gorillas form harems which may include two full-grown males. One third of gorilla groups in East Africa have two grown males in their group.

Most primates are bonded together by the relationship between females, a pattern also seen in many human families. Once they reach maturity, both females and males usually leave the group. Females usually join another group or a lone silverback adult male, whereas males may stay together temporarily, until they attract females and establish their own groups. It is commonly believed that the structure of the gorilla group is to prevent predation

A female will give birth to a single infant after a gestation period of about 8½ months. They breastfeed for about three years. The baby can crawl at around nine weeks old and can walk at about 35 weeks old. Infant gorillas normally stay with their mother for three to four years and mature at around 8 years old (females) and 12 years old (males).

The western lowland gorilla (Gorilla gorilla gorilla) is one of two subspecies of the western gorilla (Gorilla gorilla) that lives in montane, primary and secondary forests and lowland swamps in central Africa in Angola, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Equatorial Guinea and Gabon. It is the nominate subspecies of the western gorilla, and the smallest of the four gorilla subspecies.

The western lowland gorilla is the only subspecies kept in zoos with the exception of Amahoro, a female eastern lowland gorilla at Antwerp Zoo and a few mountain gorillas kept captive in the Democratic Republic of the Congo.