It appears that Austrolopithecus was eating meat roughly 800,000 years before anthropologists previously thought was possible.
As early as 3.4 million years ago, some individuals with a taste for meat and marrow — presumably members of the species best known for the skeleton called Lucy — apparently butchered with sharp and heavy stones two large animals on the shore of a shallow lake in what is now Ethiopia. Scientists who made the discovery could not have been more surprised. They said the cut marks on a fossilized rib and thighbone were unambiguous evidence that human ancestors were using stone tools and sometimes consuming meat at least 800,000 years earlier than previously established. The oldest confirmed stone tools are less than 2.6 million years old, perhaps only a little before the emergence of the genus Homo.This is a hugely important discovery. It also gives credence to the theory that eating meat, first as scavengers and later as hunters helped early humans to develop a much higher level of intelligence. When our first distant ancestors climbed down from the trees to begin our journey as humans, they ate only fruits and vegetables. After climbing down they added tubers, etc. It's not a diet that has a very high calory countent, nor does it lend much to the development of high intelligence, because it requires a large or long digestive system which has it's own drawbacks.
"You can't have a large brain and big guts at the same time," explains Leslie Aiello, an anthropologist and director of the Wenner-Gren Foundation in New York City, which funds research on evolution. Digestion, she says, was the energy-hog of our primate ancestor's body. The brain was the poor stepsister who got the leftovers.High energy levels require much more fuel than a browsing on a vegan diet does. That can only come from protein.
"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," Aiello says. That period is when cut marks on animal bones appeared — not a predator's tooth marks, but incisions that could have been made only by a sharp tool. That's one sign of our carnivorous conversion. But Aiello's favorite clue is somewhat ickier — it's a tapeworm. "The closest relative of human tapeworms are tapeworms that affect African hyenas and wild dogs," she says. So sometime in our evolutionary history, she explains, "we actually shared saliva with wild dogs and hyenas." That would have happened if, say, we were scavenging on the same carcass that hyenas were. But dining with dogs was worth it. Meat is packed with lots of calories and fat. Our brain — which uses about 20 times as much energy as the equivalent amount of muscle — piped up and said, "Please, sir, I want some more." [read the whole thing!]I'll take my steak rare please...