How Strong Is a Gorilla? Facts Behind the Famous Strength

Why nobody has measured gorilla strength

Measuring strength requires a test of maximum effort, such as lifting a weight or pulling a handle as hard as possible. Humans can be asked to try their hardest; gorillas cannot. A gorilla that pulls lightly on a rope may simply not be trying, and pushing a wild animal of over 150 kg (330 lb) to its limit is neither safe nor ethical.

As a result, there is no published scientific test of a gorilla’s lifting or pulling strength. Numbers that circulate online, such as a gorilla lifting 800 kg or even 2,000 kg (1,800 or 4,400 lb), have no known source in a study. The same is true of claims that one silverback has the strength of several weightlifters: these are colorful comparisons, not measurements.

The closest real evidence comes from our other great ape relative. Early 20th-century pulling tests suggested chimpanzees were five to eight times stronger than men, but a 2017 study in the Proceedings of the National Academy of Sciences found that, size for size, chimpanzee muscle produces only about 1.35 times the force and power of human muscle (see How strong is a chimpanzee?). Gorilla muscle has not been studied in the same detail, but there is no reason to think it is dramatically different.

Where a gorilla’s strength comes from

The main reason gorillas are so strong is simply size. Wild adult males, called silverbacks, usually weigh about 140–230 kg (310–500 lb), roughly two to three times as much as an average man, and much of that weight is muscle. Females weigh about 60–100 kg (130–220 lb).

Several features add to this power:

• Massive upper body: gorillas have a broad chest, thick neck and very long, heavily muscled arms. An adult male’s arm span is about 2.3–2.6 m (7 ft 7 in–8 ft 6 in).
• Large hands: the hands are broad with thick fingers, and the arms carry much of the body’s weight during knuckle-walking.
• Strong jaws: adult males have a tall bony crest on top of the skull that anchors huge chewing muscles, used to grind tough stems, bark and pith all day.
• Muscle type: like chimpanzees, gorillas probably have a higher share of fast-twitch muscle fibers than humans, which favor short bursts of power over endurance.

Size for size, then, a gorilla is probably stronger than a person, perhaps by a similar modest margin as a chimpanzee. In absolute terms the gap is much larger, because the gorilla is so much bigger.

How gorillas use their strength in the wild

Most of a gorilla’s strength goes into ordinary daily life rather than fighting. Gorillas pull down and break thick plant stems, strip bark, tear open rotten logs for insects and split woody shoots to reach the soft pith inside. Mountain gorillas in East Africa can snap stems of bamboo and wild celery with their hands. Gorillas also haul their heavy bodies up into trees to reach fruit and leaves, and they build a new nest every evening by bending and breaking branches.

Their feeding is impressive in itself. An adult male mountain gorilla in one year-long study ate around 19 kg (41 lb) of plant food a day, much of it tough and fibrous. You can read more about this in What do gorillas eat?

Chest-beating and displays

The most famous show of gorilla strength is a display rather than an attack. A silverback facing a rival or a threat may hoot, rise onto two legs, throw vegetation, beat his chest with cupped hands, run sideways, tear at plants and slap the ground. The chest-beating makes a hollow popping sound that can carry about a kilometer (over half a mile) through the forest.

These displays are mostly bluff. They let males show off their size and vigor without risking injury, and most charges stop short or veer away. Research on mountain gorillas suggests that larger males produce lower-pitched chest beats, so the sound may help rivals judge each other’s size.

Real fights do happen, mainly when two groups meet or when an outside male tries to take over a group. Silverbacks fight with their teeth as well as their arms, and their long canines can cause deep wounds. Such serious fights are rare.

Gorilla strength compared with other animals

In total strength, a gorilla easily beats chimpanzees and humans. A large bear or an elephant is stronger still, simply because it is so much heavier. In strength relative to body weight, small animals such as beetles and ants far outdo any ape. See the strongest animals for how these comparisons work.

Are gorillas dangerous to people?

Despite their strength, gorillas are shy and usually calm. Wild gorillas normally move away from people, and the rare attacks on record mostly involved animals that were surprised, cornered, injured or protecting their young. Habituated gorillas visited by tourists in Uganda, Rwanda, the Democratic Republic of the Congo, Gabon and the Central African Republic can be watched safely when visitors follow the guides and keep a distance of at least 7 m (23 ft).

The best way to respect a gorilla’s strength is never to approach, crowd or provoke one, in the wild or in a zoo. If anyone is injured by a wild animal, seek emergency medical help immediately.

You can learn more about the two species in our profiles of the western gorilla and the eastern gorilla.