This paper was submitted 18 II 08 and accepted 7 V 08.
I was teaching at Makerere University in Kampala when Cliff Jolly took a sabbatical in Uganda, and it was then that I observed the amazing strength of chimpanzees. I was trying to observe and record chimpanzee locomotion in Budongo Forest in northern Uganda. On one occasion, I was minding my own business while walking along a forest trail when I nearly bumped into an adult male chimpanzee that was doing the same. The frightened animal swung at a nearby tree buttress root, making a resonating booming sound. After this display, the animal raced up the trunk and proceeded to shake branches high above me. When my heart rate returned to normal, I tried to imitate the chimpanzee by banging on the buttress as hard as I could. I could produce only a laughably feeble sound. Thus it was that I came to appreciate firsthand what many people know anecdotally—that great apes are immensely strong.
Bauman (1923, 1926) showed that adult male and female chimpanzees held long in captivity were much stronger than any of several fit young football players when normalized for body mass. He had the animals (when they felt like it) and the students pull on a calibrated metal loop dynamometer. The female recorded a two‐handed pull of 1,260 pounds, while the male recorded a one‐handed pull of 847 pounds. The strongest student managed a one‐handed pull of 210 pounds and a two‐handed pull of 491 pounds. When normalized for body mass, this meant that the chimpanzees were more than four times as strong as the men. But note that Finch (1943) could not persuade several chimps at the Yale Primate Laboratory to match a single male human in pulling strength when pulling on a rope for food items—unlike students, apes cannot always be trained to behave.
Those of us who have watched great apes at close quarters are not surprised when reading Bauman’s account. He asked the obvious question, “To what factors do they owe this very striking superiority?” And the related questions on his list are some of those that we ask today: Are the ape muscle fibers intrinsically stronger? Are the motor nerve impulses different? Or is it a combination of the two?
Bauman went on to speculate about the human ancestral condition, mentioning Neanderthals particularly. Bauman did not address the effect of the skeletal levers or muscle and tendon architecture, and following Smith and Savage (1956), we would add those to the list today. Also, we might ask about the importance of neuromuscular control in locomotion.
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