Gorillas are the world’s largest living primates, found exclusively in the tropical and subtropical forests of Central Africa. These ground-dwelling, herbivorous apes belong to the genus Gorilla. Scientists recognize two distinct species, each divided into two subspecies. This classification helps distinguish differences in their appearance, behavior, and the conservation challenges they face.
The Two Primary Species
The genus Gorilla is split into two species: the Western Gorilla (Gorilla gorilla) and the Eastern Gorilla (Gorilla beringei). This division occurred approximately two million years ago, separated by the geographic barrier of the Congo River. Western Gorillas inhabit west-central Africa, while Eastern Gorillas live in east-central Africa.
Eastern Gorillas are the larger species, possessing a broader chest and a longer face. Western Gorillas are smaller and have a lighter, brownish-grey coat, sometimes including a reddish chest patch. The Western Gorilla population, estimated to be over 316,000, is significantly larger than the Eastern Gorilla population, which is fewer than 5,000 individuals.
Western Gorilla Varieties
The Western Gorilla species (Gorilla gorilla) includes two subspecies: the Western Lowland Gorilla (G. g. gorilla) and the Cross River Gorilla (G. g. diehli).
Western Lowland Gorilla
The Western Lowland Gorilla is the most numerous and widespread of all gorilla types. They range across a vast area of Central Africa, including Cameroon, the Central African Republic, Equatorial Guinea, Gabon, and the Republic of Congo. This subspecies is the smallest and most agile, which aids navigation through the dense lowland rainforests and swamp forests they inhabit. Their coat is a lighter brownish-grey, often displaying a reddish-brown cap of hair on the forehead. While accurate population counts are difficult due to their remote habitat, their numbers are estimated to be well over 100,000.
Cross River Gorilla
The Cross River Gorilla is the world’s rarest great ape, with estimates suggesting fewer than 300 individuals remain. This subspecies is restricted to a small, fragmented area of highland forest on the border between Nigeria and Cameroon. They are similar in size to the Western Lowland Gorilla, but they have been observed to have smaller hands, feet, and a slightly different skull and tooth structure. Their isolated population makes them especially susceptible to localized threats and genetic issues.
Eastern Gorilla Varieties
The Eastern Gorilla species (Gorilla beringei) divides into two subspecies: the Mountain Gorilla (G. b. beringei) and Grauer’s Gorilla (G. b. graueri), also known as the Eastern Lowland Gorilla.
Grauer’s Gorilla
Grauer’s Gorilla is the largest of all gorilla subspecies and is found only in the eastern Democratic Republic of Congo (DRC). They possess a robust build, a broad chest, and a dark, thick coat. Their numbers have plummeted by over 77% since the mid-1990s due to civil unrest and illegal hunting.
Mountain Gorilla
The Mountain Gorilla is perhaps the most well-known subspecies, inhabiting the high-altitude, cold cloud forests of the Virunga Volcanoes and the Bwindi Impenetrable Forest. This range includes parts of the DRC, Rwanda, and Uganda. They have the thickest and longest fur, an adaptation for surviving in their cold, mountainous environment, which can reach altitudes up to 4,300 meters. Intensive conservation efforts have resulted in a positive population trend, increasing their numbers to over 1,000 individuals. They are slightly smaller than Grauer’s Gorillas and tend to have a bluish-black coat color.
Protecting the Different Types
All four gorilla subspecies are currently listed under high threat classifications by the International Union for Conservation of Nature (IUCN). The Western Lowland Gorilla, Cross River Gorilla, and Grauer’s Gorilla are all classified as Critically Endangered. The Mountain Gorilla has been reclassified to Endangered, reflecting the success of focused conservation programs.
Gorillas face severe threats across their range. These include habitat destruction from mining and agriculture, which fragments their populations. Illegal poaching for the bushmeat trade remains a significant factor in their decline, particularly for the Western and Grauer’s Gorillas. Disease, such as the Ebola virus, also poses a major risk, especially to the densely populated Western Lowland Gorillas.
Conservation efforts focus on anti-poaching patrols to deter illegal hunting and on monitoring the small, fragmented groups. Ecotourism, particularly for the Mountain Gorilla, generates revenue that funds these protective measures. This also provides direct economic benefits to local communities. The long-term survival of all four types requires continued international support and stability in the regions where they reside.