Gorillas are the largest living primates, massive apes whose size and bulk command respect in the tropical forests of equatorial Africa. Their dimensions vary significantly based on both sex and specific species classification. These differences are a result of evolutionary pressures related to social structure, competition, and the various habitats they occupy across the continent. Understanding their physical metrics requires looking closely at mass, linear dimensions, and the distinctions between the four recognized subspecies.
Adult Gorillas: Weight and Bulk
The most striking feature of gorilla size is the dramatic sexual dimorphism, which results in a massive weight disparity between adult males and females. Mature male gorillas, known as silverbacks due to the patch of white hair that develops on their backs, can weigh between 136 and 227 kilograms (300 to 500 pounds) in the wild. Adult females, by contrast, typically weigh about half as much, with a range of 68 to 113 kilograms (150 to 250 pounds).
This difference in weight is attributed to the male’s prolonged growth period, a phenomenon known as bimaturation, which allows them to continue gaining mass long after females have stopped growing. The immense bulk of the silverback is directly related to his role as the dominant leader and protector of his troop. However, these figures represent gorillas living in their natural environment; gorillas in captivity, benefiting from consistent and abundant diets, can sometimes become overweight and reach weights exceeding 270 kilograms (600 pounds), with some recorded individuals hitting up to 310 kilograms.
Dimensions: Height and Arm Span
While their weight conveys their mass, their height and reach provide a sense of their imposing stature. Gorillas primarily move by “knuckle-walking,” a quadrupedal gait that makes them appear shorter than their true standing height. When an adult male stands erect, which they do only occasionally or during chest-beating displays, his height can range from 1.4 to 1.8 meters (4 feet 7 inches to 5 feet 11 inches).
Female gorillas are noticeably shorter, generally standing between 1.25 and 1.5 meters (4 feet 1 inch to 4 feet 11 inches) tall. A male’s upper body bulk is also evident in his impressive chest circumference, which can measure almost two meters (6 feet 6 inches) around. The arm span, or reach, of the gorilla is significantly greater than its standing height. A large silverback’s arms can stretch up to 2.6 meters (8 feet 6 inches) from fingertip to fingertip, providing a mechanical advantage for locomotion and foraging.
Size Differences Among Species
The size of a gorilla is not uniform across the genus, which is divided into two species and four subspecies, with the Eastern gorilla species generally being the larger. The Grauer’s gorilla, also known as the Eastern Lowland gorilla (Gorilla beringei graueri), is widely recognized as the largest of all the subspecies. Adult male Grauer’s gorillas have a mean mass of approximately 220 kilograms (484 pounds) and can stand up to 1.85 meters tall when fully erect.
The other Eastern subspecies, the Mountain gorilla (Gorilla beringei beringei), is also a massive animal, with males reaching weights up to 220 kilograms as well. Western gorillas are noticeably smaller than their Eastern relatives, with the Western Lowland gorilla (Gorilla gorilla gorilla) males having an average mass closer to 170 kilograms (374 pounds) and a standing height of around 1.7 meters. The smallest subspecies, the Cross River gorilla (Gorilla gorilla diehli), is estimated to have adult males weighing approximately 180 kilograms (396 pounds).