Gona is the scene of a long-forgotten leap in human consciousness.
A monument should be erected at this spot in the dun badlands of Afar country: a tall shrine, made exclusively of stone, to honor the colossal idea that unfolded here 2.6 million years ago. The world’s potentates could be invited to the inauguration. A new international holiday—called Gona Day, perhaps—might justifiably be added to the crowded global calendar of worthy human events. But VIP status at any such ceremony could only be reserved for the chefs of the planet—the sushi artists of Osaka, the Paris masters of steak tartare, and, in particular, the carvers of beef in Argentina and Texas. I imagine them doffing their toques and raising their knives and cleavers, saluting the location of the oldest stone tools in the world. They would bow to honor their gastronomic Eves, their culinary Adams.
The Rift Valley of Africa is littered with millions of artifacts from the basement of time. The majority of these implements (or garbage heaps) appear to be linked to one purpose: food preparation. Gona, then, is humankind’s original kitchen. Its primordial chopping and cutting tools, whose simple design, called Oldowan, overcame our ancestors’ competitive disadvantages—weak bodies and small teeth designed mostly to chew plants—sliced open the concentrated, animal energy of entire ecosystems: a revolution.
“The first toolmakers began making stone artifacts intentionally by knocking off cobbles to produce sharp-edged flakes used for cutting up animal carcasses,” says Sileshi Semaw, an Ethiopian scientist at the National Research Center for Human Evolution, in Spain, who discovered the Gona site. “The stone tools were mainly used for processing animal carcasses for meat and for breaking bones for marrow.”
Gona’s blades were probably not used to kill the archaic antelopes whose hacked, fossilized bones lay scattered there. The first toolmakers were not brave hunters. Instead, the wily, squinting hominids who knocked two rocks together at Gona, announcing their conquest of the world, were likely “power scavengers.” They spooked hyenas and wild dogs from their kills. They ate the work of others.
We have walked for weeks, Ahmed Alema Hessan and I, atop discarded Stone Age cutlery—the litter of ancient meat-gorged bacchanals in a landscape often equated, today, with hunger.
We yo-yoed for miles across waterless gullies to Gona. Its silence rang. We toppled, exhausted, devastated by the heat, under the spiky shade of an acacia. Yet even there we sizzled. And couldn’t linger. There were reports of armed Issa nearby, rustling Afar cattle.
“Let’s go, man,” Alema said, kicking my boots.
History is a mirror. The revolution continues.
Did Fire Make Us Human? The Raw Truth about Cooking
Most people who study human origins agree that the invention of stone tools around 2.6 million years ago was a seminal crossroad in human evolution. Animal butchery allowed hominids to tap nutrient-rich sources of food such as internal organs and marrow. Richer energy inputs may have nurtured our big brains. But one researcher, Richard Wrangham of Harvard, thinks the more important breakthrough came with the power of the hearth—cooking. Wrangham’s stance is controversial, because solid evidence for controlled fire is relatively recent: only about 400,000 years old. Below, Wrangham warms to his topic.
I walked through the remote Gona site in Ethiopia, which at 2.6 million years old is considered to be the oldest stone tool site in existence. The tools scattered across the desert there—hand axes, picks—were used mostly to butcher large animals, such as buffalo, which were presumably eaten raw. What do we know about the amount of raw meat in our prehistoric diets? We have canines for a reason, right?
Cut marks in the meat-bearing regions of fossil bones confirm that a species of hominid was eating meat from large animals more than two million years ago. Very likely the meat-eaters were ancestors of ours; some of the first ones to have regularly used stone tools were probably the “intermediate” species Homo/Australopithecus habilis. Unfortunately we do not know how much meat they ate, or whether they cooked it. Their digestive systems must have been adapted to eating a lot of plants, as they are in chimpanzees and gorillas today, so it is unlikely that they relied on meat for most of their food. A reasonable guess is that they ate their meat raw when they first started taking it from big game animals like antelope and hippos, and then learned over some tens of thousands of years that cooking improved it. By the way, canine teeth have nothing to do with meat-eating in primates. Species with big canines do a lot of fighting with each other. Mostly the ones with big canines are males, such as gorillas and baboons, but in some species like gibbons females have big canines too: They fight hard with other female gibbons.
You argue that crossing the threshold from raw foods to cooked foods was a key milestone that helped make us fully human—or, rather, made our brains more human. Why?
Cooked food is different in two very important ways from raw food. It gives us more energy, and it is softer. The increase in energy means that once they started relying on cooked food, our ancestors could live longer, have more babies, travel farther, fuel a big brain, and give up having voluminous guts. The softer food given by cooking allowed our ancestors to have small teeth, spend less time chewing, and more time on novel activities like hunting and tool-making. Brains use a lot of calories per day. Cooked diets helped brains enlarge because humans have small guts (thanks to eating soft, easily digested food), so some of the energy that had previously been used to power our guts could now be used for brains.
Why, exactly, is cooked cuisine more nutritious than raw food?
First, cooked food gives us more calories per gram of food that we eat. This is because the heat of cooking opens up molecules and makes them more easily split by enzymes. For instance cooking gelatinizes starch and denatures proteins. If starch or protein are eaten raw they are only partly digested in the small intestine, and then the half or more that remains is digested (or “fermented” by bacteria) very inefficiently in the large intestine. Second, cooked food costs us less of our body’s energy to digest. This is because cooked food is so relatively soft that our guts can break it down into smaller and smaller bits without too much muscular action in the stomach, or production of acids and enzymes. We do not know the typical amount by which cooking increases the energy value of foods, but it is probably closer to a 50 percent increase than 10 percent.
Your theory holds that the bigger brains and smaller teeth of Homo erectus, our first ancestor to diverge convincingly from earlier, more apelike lines about 1.9 million years ago, is the result of eating cooked food. But other experts say that the evidence of controlled fire for cooking is a much more recent invention, dating back only about 400,000 years. How do respond to this critique?
My theory is predictive. It says that if we look hard enough, we will find evidence of hominids controlling fire by around 1.9 million years ago. Other kinds of data might help too, such as evidence of genetic adaptation to cooked food. The cooking theory is based on a biological argument, whereas the challenge comes from archaeology.
We’ve been gathering around hearths for a very long time. Modern suburbanites build fake electric fireplaces in their ranchette-style homes. Why is it so pleasurable to stare into fire embers? Does it tap some limbic memory of a full belly to come?
Regardless of exactly when fire was first controlled, a fireplace has certainly been a critical part of human life for hundreds of thousands of years. It has been a place of safety, satisfaction, meals, and camaraderie. No wonder that everyone loves it.