Gorillas are the largest living primates, inhabiting the tropical and subtropical forests of Central Africa. They are divided into two species and four subspecies, each adapted to its specific forest environment. While often portrayed as aggressive, gorillas are generally peaceful herbivores whose sheer size commands respect in their ecosystems.
Primary Metrics of Gorilla Size
The most massive gorillas are mature males, known as silverbacks, representing the maximum size potential of the species. A mature male gorilla can weigh between 136 and 270 kilograms (300 to 600 pounds) in the wild, though the upper end of this range is exceptional. When standing upright, a silverback can reach a height of 1.4 to 1.8 meters (4 feet 7 inches to 5 feet 11 inches). This standing measurement is often less relevant than their weight, as they typically move on all fours in a knuckle-walking posture.
Wild adult females are considerably smaller, typically weighing 68 to 113 kilograms (150 to 250 pounds). Their standing height generally ranges from 1.25 to 1.5 meters (4 feet 1 inch to 4 feet 11 inches). The immense weight difference highlights the pronounced sexual dimorphism within the species. Size is an important factor in the social hierarchy, with the largest silverback usually dominating the troop.
How Species and Sex Influence Size
Subspecies Variation
The size a gorilla achieves is highly dependent on its specific subspecies. The Eastern Lowland Gorilla (Grauer’s gorilla) is generally recognized as the largest subspecies, while the Western Lowland Gorilla is typically the smallest. The Mountain Gorilla is the second largest and possesses a bulkier frame with thicker fur, an adaptation for its colder, higher-altitude habitat.
Sexual Dimorphism and Male Features
Mature male silverbacks can weigh nearly twice as much as adult females. Males develop a muscular build, particularly across the shoulders and neck, supporting their role as troop protector. The prominent silver saddle of hair running down the male’s back and hips is a visual signal of full maturity and dominance.
The skull of a mature male also develops a bony ridge on the top, called the sagittal crest, which is almost absent in females. This crest anchors the powerful temporalis muscles used for chewing tough vegetation. The combination of the sagittal crest, the immense body mass, and the silver back patch defines the mature male.
Proportional Physical Dimensions
Beyond height and weight, the gorilla’s physical dimensions define its structure. A silverback’s arm span is significantly greater than its standing height, reaching up to 2.6 meters (8 feet 6 inches). This wide reach results from their long, powerful arms, which are longer than their legs and used for knuckle-walking locomotion. The wide chest of a silverback can measure nearly 1.5 meters (60 inches) in circumference, emphasizing their broad, barrel-chested build.
The gorilla’s bones are much denser than a human’s, contributing to their body weight and muscular power. Their large head features a pronounced brow ridge that overhangs the eyes. Males also develop massive, sharp canine teeth that are proportionately much larger than those of the females.
The Process of Reaching Full Size
Gorillas follow a distinct timeline of growth before reaching their full adult dimensions. Infants are highly dependent on their mothers, clinging to her fur for the first few months of life. They transition through a juvenile stage, moving independently but not yet sexually mature. This period of rapid growth lasts until approximately age six to eight.
Male gorillas enter the blackback stage, an adolescent phase where they are physically large but lack the full size and silver coloration of a mature leader. Males continue to gain size and muscle mass until they reach full physical maturity around 12 to 15 years of age. The appearance of the silver patch of hair on the back marks the final transition to a silverback. Females typically reach their full adult size and sexual maturity earlier, around 8 to 10 years old, and then primarily gain weight rather than height.