Check Out The Big Brains

And according to one scientist, it has been going on for a lot longer than originally thought.

Henry Bunn, a professor of anthropology at the University of Wisconsin at Madison, in his study from fossil evidence collected at an ancient butchery site in eastern Africa, has surmised that early man had the ability to ambush and attack large herds of animals and did it 1.6 million years earlier than previously thought, according to Great Britain’s The Observer newspaper.

And the increased amount of meat introduced into ancient man’s diet through hunting had a strong impact on the species’ evolutionary brain growth.

Speaking in September at Bordeaux, France, during the annual meeting of the European Society for the study of Human Evolution, Bunn said ancient humans learned complex hunting techniques to kill antelopes, gazelles, wildebeest and other large animals at least two million years ago.

Previously, scientists assumed that our human ancestors – small-brained, ape-like creatures – were essentially scavengers, eating meat from animals that had died of natural causes or scraps left behind by large cats and other carnivores. 

“We know that humans ate meat two million years ago,” Bunn said. “What was not clear was the source of that meat. However, we have compared the type of prey killed by lions and leopards today with the type of prey selected by humans in those days. This has shown that men and women could not have been taking kill from other animals or eating those that had died of natural causes. They were selecting and killing what they wanted.”

Bunn and his colleagues traveled to Olduvai Gorge in northern Tanzania, along the eastern portion of the Serengeti Plains. Olduvai Gorge is considered one of the most important paleoanthropological sites in the world and has been instrumental in the study of early human evolution.

At the huge butchery site, the anthropologists discovered carcasses of wildebeest, antelopes and gazelles, brought there by ancient humans more than 1.8 million years ago. The meat was then stripped from the animals’ bones and eaten.

“We decided to look at the ages of the animals that had been dragged there,” Bunn said. “By studying the teeth in the skulls that were left, we could get a very precise indication of what type of meat these early humans were consuming.”

The results from several species of large antelope analyzed showed that humans preferred only adult animals, Bunn said, while lions and leopards today kill old and young indiscriminately. For smaller antelope species, the results were slightly different. Humans preferred only older animals, while today’s lions and leopards attack mostly the adults in their prime.

“… We found a completely different pattern of meat preference between ancient humans and other carnivores,” Bunn said, “indicating that we were not just scavenging from lions and leopards and taking their leftovers. We were picking what we wanted and were killing it ourselves.”

Previously, the oldest evidence of human hunting had come from a 400,000-year-old site in Germany, where fossil evidence indicated horses had been speared and their flesh eaten.

Scientists have differing views on early human hunting instincts. According to Robin McKie of The Observer, fossil experts like Raymond Dart and writers like Robert Ardery were among those who concluded that ancient man’s desire to hunt drove them to develop spears and axes, and their growing brains evolved in order to handle and create increasingly complex weapons.

In recent decades, however, scientists have argued the evolution of the ancient brain was mainly for advanced human interaction – developing language, maintaining complex societies, ect.

“I don’t disagree with this scenario,” Bunn said. “But it has led us to downplay the hunting abilities of our early ancestors. People have dismissed them as mere scavengers, and I don’t think that looks right anymore.”

Bunn said he believes early humans likely sat in trees and waited until herds of antelopes or gazelles drew close, then speared them. The killing and eating of meat continued to have strong evolutionary implications.

Scientists studying human evolution maintain that the introduction of meat into ancient man’s diet spawned considerable brain growth. With a previous diet of mostly raw vegetable matter and fruit, digestion required much more energy in the human body, leaving only “leftover” energy for the brain, anthropologist Leslie Aiello told National Public Radio in 2010.

"What we think is that this dietary change around 2.3 million years ago was one of the major significant factors in the evolution of our own species," said Aiello, director of the Wenner-Gren Foundation, which funds research on evolution.

The increased introduction of meat – a dense, protein-rich source of energy – not only lessened the need for larger digestive tracts seen in ancient humans, but newly-diverted energy inside their bodies was used to fuel ever-growing brains.

It continued over the following two million years, and the human brain continued to grow.

And we’ve continued to hunt.