Humans' cognitive powers come from evolved hunting skills
New Delhi, Jun 27, 2013, DHNS: 4:28 IST
Almost two million years ago, our ancestors, for the first time, learnt how to hunt animals by forcefully throwing stones or sticks.
This crucial skill of hurling stones or other weapons at high speed was essential to convert early humans into hunter-gatherers, scientists have found, studying the evolution of throwing.
Though humans do not hunt anymore in such crude fashion, the same throwing skills are now visible in sports like cricket or baseball when often balls are thrown at more than 100 km an hour speed.
A team of scientists, including a Bangalorean, found three major evolutionary changes in human anatomy which help improve human throwing.
Though a few evolutionary changes took place in earlier species like Australopithecus, all of which came together in Homo erectus – one of the forefathers of modern human (Homo sapiens ) – about two million years ago.
Archaeological evidence too suggest hunting activity intensified around this time.
The first step to become a hunter is the ability to throw a projectile – a stone weapon or wooden spears for early humans – with high speed to injure and kill an animal.This was possible by a suite of changes to human shoulders and arms allowing early humans to more efficiently hunt by throwing projectiles.
Evolution of throwing helped human ancestors become part-time carnivores, paving the way for a host of later adaptations, including increases in brain size and migration out of Africa. In the new research – published in Nature -- scientists showed humans were able to generate these high speeds primarily by storing and releasing elastic energy in the ligaments and tendons that cross the shoulder.
“The ability of human throwers to store and release elastic energy is critical to throwing speed, and is possible because of three major evolutionary changes in our body,” Madhusudhan Venkadesan, one of the team members at National Centre for Biological Sciences, Bangalore told Deccan Herald.