How Strong Is a Gorilla Compared to a Human?

Stand a silverback next to an average man and the tops of their heads land at about the same height. The scale tells a different story. The gorilla weighs as much as three men, and most of the extra mass is loaded into the upper body: a barrel chest, heavy shoulders, and arms that stretch well beyond a man's height from fingertip to fingertip.

So the obvious question follows. How much stronger does that body make him? There is a real answer, and it arrives with an honest asterisk attached.

The short answer

A mature male gorilla weighs 160 to 230 kilograms, and exceptional males pass 270. Comparative anatomy puts his strength at roughly six to ten times that of a man of the same body weight. That range is an estimate, because no silverback has ever been tested on a strength machine. In practice the power works mostly as a deterrent: rival males settle most contests with displays, and the animal spends its days as a highly social, generally gentle plant eater.

Where a gorilla carries its power

A gorilla's muscle is laid out on a different plan from a human's. The bulk sits in the shoulders, chest, and arms, and the arms are enormous levers in their own right. A silverback's span measures 2.3 to 2.6 metres from one fingertip to the other, wider than most doorways.

Those arms also serve as front legs. Gorillas travel on all fours with their weight resting on folded knuckles, so the upper body bears load every time the group moves. The animal shifts its mass through forest and up steep hillsides with a quiet, unhurried economy. Muscle force rises with the size of the muscle, and a body three times a man's weight gives that rule a great deal to work with.

Why nobody can give an exact number

The six-to-ten range exists because the direct experiment is off limits. Ethics keep silverbacks away from dynamometers and weight stacks, so the estimate comes from comparative anatomy instead. Researchers set a gorilla's skeleton, musculature, and mass beside a human's and reason from that structure to the force it can produce.

That makes the figure the most honest translation available, and still a translation. Read it as a range with soft edges, and treat any tidier number you meet elsewhere as more confident than the evidence behind it. Even the low end of the range describes a gulf between the two bodies, which is exactly why the gorilla so rarely needs to use its strength.

What gorillas actually use their strength for

Most of the time, a silverback spends his strength as information. The chest beat is the famous example. He drums on his chest with cupped hands and sends a deep, hollow beat through the trees, one burst of noise that warns rivals, steadies the group, and announces his standing. When two groups meet, the silverbacks usually trade displays until the weaker side backs away.

Real fights are uncommon, and they are costly when they come. Wounds from a clash between competing silverbacks can end a male's time as leader, or end his life. The picture of the gorilla as a rampaging brute grew out of early colonial encounters and was amplified by cinema. Actual groups pass their days feeding, resting, and moving together under green cover, with the strength held in reserve.

What fuels all that muscle

Nearly everything a gorilla eats is a plant: leaves, stems, roots, bark, and fruit, topped up now and then with ants and termites. The balance shifts with habitat. Mountain gorillas live mostly on foliage, while lowland gorillas eat more fruit wherever it is plentiful. That choice reshapes the whole day, because fruit trees stand farther apart than continuous greenery, so fruit-eating groups walk longer routes between meals.

How closely related are gorillas to humans?

Close enough to make the strength gap striking. Humans and gorillas share roughly 98.3 percent of their DNA, while humans and mice share about 85 percent. A person and a gorilla are genetically nearer to each other than a gorilla and an orangutan are. The two lines have evolved separately for about 10 million years, and only the chimpanzee is a closer living relative.

The family tree is also more tangled than it looks. When the gorilla genome was sequenced, the team found that across about 15 percent of the human genome, our DNA sits closer to the gorilla's than to the chimpanzee's, according to the gorilla genome study published in Nature in 2012.

Two species, four kinds of gorilla

The word gorilla covers two species, and each divides into two subspecies, the regional forms within a species.

• Western lowland gorilla (Gorilla gorilla gorilla): the most numerous form, spread through the Congo Basin rainforest of Cameroon, Equatorial Guinea, Gabon, the Central African Republic, and the Republic of Congo.
• Cross River gorilla (Gorilla gorilla diehli): the other western form, numbering fewer than 250 and confined to a small area along the border between Nigeria and Cameroon, which makes it one of the rarest primates alive.
• Mountain gorilla (Gorilla beringei beringei): an eastern form, living on the Virunga volcano chain and in Bwindi Impenetrable Forest.
• Grauer's gorilla (Gorilla beringei graueri): the second eastern form, also called the eastern lowland gorilla, found in the eastern Democratic Republic of Congo.

Across all four, a silverback earns his name the same way. As a male matures, a saddle of silver hair spreads across his back.

Strength is only the first fact

The muscle is what people notice first, and it is far from the whole animal. Gorillas solve problems, use objects as tools, share a vocabulary of gestures, and keep long memories of faces and events. Studies of gorillas in captivity have repeatedly stretched what scientists thought a non-human mind could manage, and the same abilities are at work in the wild, mostly out of sight beneath the canopy. The strongest ape on Earth is also one of our nearest kin, and its muscle turns out to be the plainest thing about it.

Key terms

Silverback

The adult male who leads and guards a gorilla group. The name comes from the silver hair that spreads across his back as he matures.

Comparative anatomy

The study of how body structures differ between species. It is the basis for estimating gorilla strength, which cannot be measured directly.

Chest-beating display

A silverback's drumming on his chest with cupped hands, a show of size and status that usually settles a dispute before it becomes a fight.

Subspecies

A distinct regional form within a species. Gorillas have four, grouped into two species.

Related field notes

For how gorillas build their bodies, their groups, and their daily routines around all that power, browse more Gorillas Decoded field notes.

This article is adapted from The Strongest Ape on Earth, the opening chapter of Gorillas Decoded. The book goes on to follow how the largest ape lives, talks, and thinks, and what it will take to keep all four kinds of gorilla in the wild.