Early humans evolved to throw about two millions years ago, according to new research. Anatomy changes found in the extinct species Homo erectus allowed this ability to evolve. Archaeological evidence suggests hunting intensified during this time, which scientists now attribute to the ability to throw. Researchers tell the journal Nature that the ability helped early hunters to evolve and migrate around the globe.
The ability to throw at very high speeds is unique to humans. We can throw much faster than our closest living relative – the chimpanzee – which can only reach speeds of 20mph compared to 90mph that many professional athletes can reach. To investigate the evolutionary development of the ability to throw, scientists first had to understand the biomechanics of throwing today. They recorded the throwing movements of college baseball players using motion capture cameras and observed that the shoulder acts like a slingshot as the arm rotates backwards.
The maximum shoulder rotation (pictured middle) is when elastic energy is able to power the throw
The ligaments and tendons surrounding the shoulder then stretch and store elastic energy, which powers the forward throw. When this energy is released it generates what scientists found was the fastest motion the human body produces.
Neil Roach, from George Washington University, US, who led the study, said that changes in the anatomy of hominins (early humans) that occurred two millions years ago, enabled energy storage in the shoulder that allowed fast throwing, and therefore hunting, to occur.
“Success at hunting allowed our ancestors to become part-time carnivores, eating more calorie-rich meat and fat and dramatically improving the quality of their diet. “This dietary change led to seismic shifts in our ancestors’ biology, allowing them to grow larger bodies, larger brains, and to have more children, and it also did interesting things to our social structure. “We start to see the origins of divisions of labour around that time, where some would be hunting, others would be gathering new foods. “It probably also allowed us to move to new environments, such as areas that did not have vegetation to support us before we had the ability to hunt,” Dr Roach told BBC News. He added that it was important to remember “that what we think about hunting and behaviour is still a hypothesis” and further studies were needed. More here Origins of human throwing unlocked.