Gorillas are the largest living primates, known for their immense size, weight, and power. Their dimensions vary significantly depending on sex and the specific subspecies.
The Dramatic Difference Between Males and Females
Gorillas exhibit pronounced sexual dimorphism, meaning there is a substantial size difference between males and females. Adult males, known as silverbacks, weigh between 140 and 220 kilograms (300 to 485 pounds) in the wild. Females are much smaller, generally weighing between 70 and 115 kilograms (150 to 250 pounds), often making them about half the size of the dominant male.
This difference is also visible in height. A standing male can reach 1.4 to 1.8 meters (4 feet 7 inches to 5 feet 11 inches), while females are generally shorter, around 1.25 to 1.5 meters (4 feet 1 inch to 4 feet 11 inches) tall. The male’s size is visually emphasized by the “silver saddle,” a patch of silver-gray hair that develops across their back and hips upon reaching maturity. This feature gives the male the name “silverback” and marks his dominant status.
Size Variation Across the Four Subspecies
Gorilla size depends largely on which of the four recognized subspecies it belongs to. The genus Gorilla is divided into two species (Eastern and Western), each containing two subspecies:
- Western Lowland Gorilla (G. g. gorilla)
- Cross River Gorilla (G. g. diehli)
- Eastern Lowland Gorilla (Grauer’s) (G. b. graueri)
- Mountain Gorilla (G. b. beringei)
The Eastern Lowland gorilla is often considered the largest, with adult males averaging 160 to 180 kilograms (350 to 400 pounds) and reaching heights of 1.75 meters or more. The Mountain Gorilla is also large, with males averaging 150 to 160 kilograms (330 to 350 pounds). They appear more bulky due to their long, dense fur, an adaptation to their high-altitude habitat.
Conversely, the Western Lowland Gorilla is generally the smallest, with males typically weighing between 140 and 160 kilograms (300 to 350 pounds). The Cross River Gorilla is similar in size, with male estimates around 180 kilograms (396 pounds).
Differences in habitat and diet influence these size variations. Lowland gorillas consume more fruit and are more arboreal, tending to be less stocky and more slender. Mountain gorillas rely heavily on bulky, fibrous terrestrial vegetation, leading them to evolve a thicker build and larger internal structure to process this diet.
Physical Dimensions Beyond Weight
Other physical measurements contribute to the gorilla’s massive size beyond weight and standing height. The arm span of an adult male stretches approximately 2.3 to 2.6 meters (7 feet 7 inches to 8 feet 6 inches) from fingertip to fingertip. This arm length is significantly greater than their standing height, facilitating their primary mode of movement, known as knuckle-walking.
When gorillas stand bipedally for short distances or displays of dominance, they can reach 1.7 to 1.8 meters (5 feet 7 inches to 5 feet 11 inches) in height. This posture reveals their broad, muscular torso and chest circumference, which can measure up to 1.5 meters (5 feet) in the largest males.