A young male chimpanzee grabs a low branch, swings his whole body up in one pull and is gone into the canopy. No gym, no warm-up. It looks effortless, and that is where the legend of chimp “super strength” begins.
How strong is a chimpanzee? Stronger than a person of the same size, but not by much. A 2017 study in the journal PNAS found that chimp muscle makes about 1.35 times the force and power of human muscle of a similar size. The famous claim that chimps are “5 to 8 times stronger” traces back to one dramatic test in the 1920s.
Key takeaways
- About 1.35 times: muscle for muscle, chimps produce about 35% more force and power than humans (O’Neill et al. 2017).
- The secret is fibre type: about 67% of chimp muscle fibres are fast-twitch, built for bursts of power.
- “5 to 8 times” is a zombie statistic: it grew out of one angry pull by a chimp named Suzette in 1923.
How strong is a chimpanzee, really?
Muscle for muscle, about 1.35 times stronger than a human. Matthew O’Neill and colleagues measured single muscle fibres from chimps and people, then built computer models of whole muscles. They found chimp muscle produces about 1.35 times more maximum force and power. Their review of older studies gave a similar average of about 1.5 times.
There is a catch. Chimps are smaller than most adults. A male chimp weighs 40 to 55 kg (90 to 120 lb) and a female 32 to 45 kg (70 to 100 lb), says San Diego Zoo Wildlife Alliance. So a chimp is stronger pound for pound, but a big, fit adult has more total muscle to work with.
| Test | What was measured | Result | How much stronger than a human? |
|---|---|---|---|
| Bauman, 1923 (Bronx Zoo) | One female chimp, Suzette, pulling a rope on a gauge | 571 kg (1,260 lb), vs 151 kg (332 lb) for a college student of her weight | About 4 times, from one angry pull |
| Finch, 1943 (Yale) | Several chimps pulling ropes for food | It took an 86 kg (190 lb) man to beat a 49 kg (107 lb) chimp | Around 1.5 to 2 times per kilogram |
| Review of earlier studies (in O’Neill et al. 2017) | Average across earlier strength and jumping tests | About 1.5 times per kilogram | About 1.5 times |
| O’Neill et al., 2017 (PNAS) | Single muscle fibres in the lab, plus whole-muscle computer models | About 1.35 times the maximum force and power | About 1.35 times, muscle for muscle |
The Bauman and Finch results are as quoted in Scholz and colleagues (2006). The “how much stronger” figures for those two tests are our own arithmetic from the published numbers.
Why are chimpanzees stronger than humans?
Mainly because of the kind of muscle fibres they have. About 67% of chimp muscle fibres are fast-twitch, which give quick, powerful bursts, reports the 2017 PNAS study. That is about twice the share in human muscle. Single fibres were surprisingly similar in both species; the mix of fibres, and fibre length, made the difference.
Human muscle has a high share of slow-twitch fibres, which tire slowly and suit walking and running long distances, explains the University of Arizona release on the study. The authors think our ancestors traded some power for stamina over the last 7 to 8 million years, as walking and steady, repeated effort became more useful than bursts of strength.
Build and lifestyle add to it. Chimps have long, powerful arms and spend their days climbing, swinging and knuckle-walking, according to San Diego Zoo Wildlife Alliance.
Picture it: you vs a chimp
Imagine you and a chimp each have exactly the same amount of leg muscle. Here is how the 2017 study says that muscle compares. Bars are drawn to scale.
Your muscle: maximum force and power 100
Chimp muscle of the same size: about 135
The old “5 times stronger” myth would look like this: 500
(This bar would need to be almost four times wider than the chimp bar to fit on the page.)
In everyday terms: if you can just about lift a 20 kg suitcase onto a shelf, a chimp with the same amount of muscle could manage about 27 kg (20 × 1.35). Impressive, but not superhero stuff. You would still win a long walk: your slow-twitch muscle keeps going after the chimp’s has tired.
| You | Chimpanzee | |
|---|---|---|
| Force and power, same muscle size | 1× | About 1.35× |
| Fast-twitch fibres | About half the chimp’s share | About 67% |
| Best at | Endurance: walking and running far | Bursts: climbing, jumping, yanking |
| Adult body weight | Varies | 40–55 kg male; 32–45 kg female |
Sources: O’Neill et al. 2017; University of Arizona; San Diego Zoo Wildlife Alliance.
Where did the “5 to 8 times stronger” myth come from?
Mostly from one chimp on one day in the 1920s. At the Bronx Zoo, a female chimp named Suzette pulled 571 kg (1,260 lb) on a rope gauge, while a college student of her weight managed about 151 kg (332 lb). That single, angry pull was quoted for decades, and the gap grew with each retelling.
When Glen Finch tested chimps at Yale in 1943, the results were far less dramatic. It still took an 86 kg (190 lb) man to beat a 49 kg (107 lb) chimp in a rope pull, but that is nothing like five times, as summarised by Scholz and colleagues. The PNAS abstract itself notes that “super strength” stories go back to at least the 1920s, and that a critical review of the data points to a more modest advantage.
How strong is a chimp’s grip and bite?
Nobody has measured either one properly. You may read that a chimp’s grip is 200 kg (441 lb) or 330 kg (727 lb), or that a chimp can bench press a tonne. We found no study or zoo record behind any of these numbers, so treat them as guesses. Chimps have never been tested on a bench press.
What we do know is that chimps have long canine teeth, and males use them in fights. Chimp bites can cause serious injuries, which is one reason chimps are not safe pets. For animals whose bites have been measured or modelled, see which animal has the strongest bite force.
Is a chimpanzee stronger than a gorilla?
Almost certainly not. A gorilla is several times heavier than a chimp, and more muscle means more total force. Nobody has measured gorilla strength in a controlled test, though, so there is no reliable number for either ape’s total strength. See how strong gorillas are for what is known.
Why do chimpanzees matter to the forest?
Chimps are important seed dispersers. In Uganda’s Kibale Forest, 98.5% of chimpanzee dung samples contained seeds, and passing through a chimp’s gut made seeds sprout faster and more often, found Wrangham and colleagues (1994). Chimps also hunt monkeys and small antelope.
That role is at risk. The chimpanzee is listed as Endangered on the IUCN Red List, according to a 2016 IUCN announcement. San Diego Zoo Wildlife Alliance lists the threats as hunting for meat, the illegal pet trade, killing to protect crops, and loss of forest.
Myths about chimp strength
Myth: Chimps are 5 to 8 times stronger than humans.
Fact: Muscle for muscle, they are about 1.35 times stronger (O’Neill et al. 2017). Why people believe it: one record pull in 1923 was repeated and exaggerated for a century.
Myth: A chimp can bench press 600 to 900 kg.
Fact: No chimp has ever been tested on a bench press, and no source for this figure exists. Why people believe it: it sounds like a natural follow-on from the “super strength” story.
Myth: Chimp muscle fibres are made of stronger stuff than ours.
Fact: Single fibres were similar in both species. Chimps simply have a much higher share of fast-twitch fibres. Why people believe it: it was a leading idea until the 2017 study tested it.
Test yourself
1. Muscle for muscle, how much stronger is a chimp than a human?
About 1.35 times, according to the 2017 PNAS study.
2. What share of chimp muscle fibres are fast-twitch?
About 67%.
3. Where does the “5 to 8 times stronger” idea come from?
Mostly from one pull by a chimp named Suzette at the Bronx Zoo in 1923.
Where to next?
➡️ Go wider: how strong gorillas are, and how they compare with us⬆️ Go deeper: how scientists measure bite force across animals🔀 Go sideways: how strong a lion is
Frequently asked questions
Could a chimpanzee beat a human in a fight?
Almost certainly, and it could cause serious harm. A chimp is stronger for its size, climbs and moves fast, and has long canine teeth. This is one reason keeping chimps as pets is dangerous and illegal in many places, and why sanctuaries, not homes, are the right place for rescued chimps.
Is a baby chimp stronger than a human?
A baby chimp weighs about 1.9 kg (4 lb) at birth, says San Diego Zoo Wildlife Alliance, and it clings to its mother’s fur from the start. Young chimps grip well, but no measured test shows a baby chimp is stronger than a child of the same size.
Why can humans throw better than chimps?
Humans have shoulders, waists and wrists built for fast overarm throws, and our muscles suit steady effort. Chimps have more fast-twitch fibres for power, but their shoulders are built for climbing and hanging, so their throws are strong but not accurate.
How long do chimpanzees live?
In zoos, chimps live on average 32 years for males and 40 years for females, according to San Diego Zoo Wildlife Alliance. They stay close to their mothers for years, which gives them time to learn skills like using sticks to fish for termites.
Sources
- O’Neill, M. C. et al. (2017). Chimpanzee super strength and human skeletal muscle evolution. PNAS 114(28): 7343-7348.
- Phys.org / University of Arizona (2017). Chimpanzee ‘super strength’ and what it might mean in human muscle evolution.
- Scholz, M. N. et al. (2006). Vertical jumping performance of bonobo (Pan paniscus) suggests superior muscle properties. Proceedings of the Royal Society B. doi:10.1098/rspb.2006.3568.
- Wrangham, R. W., Chapman, C. A. and Chapman, L. J. (1994). Seed dispersal by forest chimpanzees in Uganda. Journal of Tropical Ecology 10: 355-368.
- San Diego Zoo Wildlife Alliance. Chimpanzee.
- IUCN (2016). Four out of six great apes one step away from extinction: IUCN Red List.
Sources checked 12 October 2026.
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