Chimpanzees are stronger than humans, but not by as much as popular myths claim. Modern research suggests they are roughly one and a half times stronger, not five to seven times.
Typical strength difference
Several biomechanical and muscle-physiology studies estimate that, pound for pound, chimpanzee muscles produce about 1.3 to 1.5 times the dynamic force and power of human muscles of similar size. This means that if a chimp and a human had the same body mass and similar training, the chimp would usually be around 30–50% stronger in explosive tasks like pulling or jumping.
The old claim that chimps are 4–5 times stronger arose from early, less controlled measurements and has been largely revised downward by more recent work. Popular science and animal-behavior overviews now generally describe chimpanzees as about 1.3–1.5 times as strong as humans rather than multiple times stronger.
Why chimps are stronger
Chimpanzee muscles tend to have a higher proportion of fast-twitch fibers, which specialize in short, powerful bursts of force. Human muscles, in contrast, contain more slow-twitch fibers that support endurance and efficient, repetitive movements such as long-distance walking and running.
There are also differences in limb structure and how muscles attach to bones, which give chimps better leverage for climbing and pulling with their arms. Humans, meanwhile, trade some raw strength for fine motor control and endurance, which supports tool use, precise hand movements, and long-distance travel.
Practical implications
In direct physical contests such as wrestling, a chimpanzee of similar size to a human would usually have a clear strength advantage because of greater power output and leverage, especially in the upper body. However, a heavier, well- trained human can offset some of this advantage, since absolute strength also depends on total muscle mass, not just muscle quality.
Even though the numerical advantage is closer to 1.3–1.5 times than 5–7, this is still significant in situations involving biting, grabbing, and rapid, explosive movements, which is why chimps are considered extremely dangerous in close contact.