Western gorilla (Gorilla gorilla)
- Gorillas are the largest of the living apes, although the Western gorilla is smaller and lighter than its Eastern relative.
- Mature male Western gorillas are known as ‘silverbacks’, and are named after silvery-white hair on their back, rump and thighs.
- A sociable species, the Western gorilla lives in family groups containing a dominant male, several females and their offspring.
- Western gorillas have been known to live for up to 40 years in the wild.
Western gorilla fact file
Western gorilla description
The gorilla is a heavily built primate and is the largest of the living apes. Until recently it was considered a single species, but DNA evidence has led to the recognition of the eastern and western populations as distinct species: Gorilla beringei and Gorilla gorilla, respectively (4) . Gorillas have a characteristic body shape with a broad chest, heavy neck and strong hands and feet. They have a fine, brownish coat, often with a red or auburn tinge on the crown, and mature males are known as ‘silverbacks’ due to the silvery-white saddle of hair extending from the back to the rump and thighs (2) . Male gorillas have a larger skull crest than females and other apes, together with larger canines and a more pronounced ridge above the eyes (2) . Western gorillas are smaller and lighter bodied than eastern gorillas, because they must be agile climbers in order to reach fruits in the trees (2) .
French Gorille. Spanish Gorila. Size Male height: up to 180 cm (2) Female height: up to 150 cm (2) Male weight: 140 kg (2) Female weight: 70 kg (2)
Western gorilla biology
Western gorillas live in groups that vary in size between 2 and 20 individuals, composed of at least one male, several females and their offspring (2) . A dominant male silverback heads the group, with younger males usually leaving the group when they reach maturity. Females transfer to another group before breeding, which begins at eight to nine years old; they care for their young infant for the first four to five years of its life (2) . There is therefore a long interval between births, which partly explains the slow population growth rates that make the western gorilla so vulnerable to poaching (6) . Due to the long gestation time, long period of parental care, and infant mortality, a female gorilla will only give birth to an offspring that survives to maturity every four to six years. Gorillas are long-lived and may survive for as long as 40 years in the wild (4) .
Fruit forms a large part of the western gorilla’s diet and they will travel further each day in search of fruiting trees than their eastern relatives (2) . The distance that gorillas travel each day while they are searching for fruit trees varies between one and four kilometres. A group’s home range may be as large as 30 square kilometres (2) .
Western gorilla range
The two subspecies of western gorilla differ markedly in their range and abundance. The Cross River gorilla (Gorilla gorilla diehli) is the most restricted of the gorillas, being found only in a few isolated populations on the Nigerian-Cameroon border (5) . In contrast, the western lowland gorilla (Gorilla gorilla gorilla) is the most widespread, being found in areas of Cameroon, the Central African Republic, Congo, Gabon, Equatorial Guinea, and the Cabinda enclave of Angola (6) .
Species with a similar range