In Dartmouth, they learned that the shoulders and elbows of a person appeared as brakes for monkeys
Researchers from Dartmouth University (Dartmouth, UK) found out why the human ancestor had elbows and shoulders. The work of scientists is presented in the journal Royal Society Open Science.
The authors used a special program to analyze videos of how chimpanzees and smoky mangabeys moved through trees in the wild. According to the researchers, the structure of the hands of a chimpanzee is more similar to a human.
They are a shoulder joint in the form of a shallow socket under the rounded outer part of the humerus. It lends itself more easily to dislocations, but provides a greater range of motion. Chimpanzees can also fully extend their arm due to the special structure of their elbows. Mangabeis, on the other hand, are more like four-legged animals.
“We found that the shoulders and elbows of chimpanzees and mangabeys had a greater angle of inclination of the joints when climbing trees, that is, primates did it in the same way. However, when descending from trees, chimpanzees extended their arms above their heads to hold on to branches, ”the scientists noted.
According to them, this indicates that the ancient ancestor of humans and other primates developed human arms to slow down the descent from the trees. The large size of the body makes the usual descent dangerous due to the high risk of falling – movable elbows and shoulders worked like brakes, not allowing him to fall.
“It’s the same anatomy of the early monkeys, but with a couple of changes. You now have a body part that can throw a spear or rocks to defend yourself, grab something you need, or help you climb somewhere. The descent from the tree prepared the anatomical basis for what developed millions of years later. When a quarterback in American football throws the ball, this movement is obtained from our monkey ancestors, ”the scientists concluded.