Chimpanzees are our closest cousins, they share 99 percent of their genes with us. Sometimes, like us, they can show aggressiveness, and attacks on humans are recorded. The worst part of these attacks is, the chimpanzees are strong. Really strong.
One of the most well-known attack came from Travis, an animal actor, who appeared in several television commercials, including spots for Coca-Cola. On February 16, 2009, he suddenly attacked his owner Sandra Herold’s 55-year-old friend Charla Nash and grievously mauled her, blinding her while severing her nose, ears, and both hands, and severely lacerating her face. He was subsequently shot dead on the arrival of the police, after trying to attack an officer. The photos of the incident were horrible, I won’t publish them here but you can search google for them (beware: the photos are really, really bad).
Here is another story about a strong men lost his face and most of his fingers to a chimpanzee attack on NY Daily News. He was in a medically induced coma for months. He’s undergone more than 60 surgeries since.
In fact, when a chimpanzee attacks, most of the damage does not come from their strength; the worst thing is: they know how to hurt a human. Because they know how to hurt a chimpanzee. They attack the face, the neck, eyes, and genitals, etc. And they are stronger than a human.
I remember I read somewhere, a male chimpanzee’s arm is four times stronger then an athlete’s arm with the same weight (the male common chimp stands up to 1.2 meters/3.9 feet high and weighs as much as 70 kg/150 lb, females are smaller – they are bigger and heavier than most people think). Apparently, some studies have revised the number down to maybe twice as strong as a human of the same weight.
I was in a zoo in 2009, watching chimpanzees. It was a hot day, and some people were giving water to the chimps. A child, he was drinking coke, shaked the tin of coke, the fluid hit the wire fence, and some drops went into a male chimp’s eye. Chimps hate water, they hate being wet. He got angry, and punched a timber, like a human being would do. Wow, it was a strong punch. Even a pro boxer would be knocked out.
So, why chimpanzees are that strong? Why are our closest cousins are much stronger than us?
The short and simple answer is: chimps are stronger than humans, because our nervous systems exert more control over our muscles. Our fine motor control prevents great feats of strength, but allows us to perform delicate and uniquely human tasks; like playing a violin, or drawing pictures.
The video published by Scientific American titled Why Are Chimps Stronger Than Humans? below claims that chimps have 3 to 5 times the strength of humans. According to the American popular science magazine, the main difference in strength between humans and chimpanzees most likely has to do with the neurological control of the muscles.
Large motor units have a neuron that connects to many muscle fibers and causes all of them to contract at once. Small motor units are where a neuron connects to only a few muscle fibers so that finer control of movement is possible.
Since humans have much more grey matter in their brain than chimps, there must be fewer neurons available to control the chimps muscles which means that more of the neurons must control large muscle units. Therefore when the chimp is contracting a muscle it is more of an all or nothing thing. Whereas humans have much more small motor units so we have finer control over the amount of force the muscle is exerting, so the problem is that we are unable to make all the small motor units fire to get the maximum strength out of the muscle, whereas the chimp is able to do that.
The differences of the anatomy is also important. Even if a 150-pound (70 kg) chimp and a human with the same weight have the same total muscle mass, the chimp will have far more of that muscle in his arms, whereas the human will have much more leg muscle. Chimps use their upper body and arms much more than humans, so their upper body, especially their arms grow stronger. When you look at the lifestyles of the typical human and the typical chimp, you see how a lot of the difference can come about: a chimp will spend its day swinging around in trees and other such muscle-intensive activities. Even a traditional hunter doesn’t get up to that level of exercise, at least not consistently.