The Triumph of Seeds by Thor Hanson Read Free Book Online Page A

stands, the starch content of a grass seed can top 70 percent, quick energy that evolved to fuel plant growth but that now fuels over half of all human activity.
    Given the abundance of grasses and their prolific, starchy seeds, it’s not surprising that our ancestors learned to take advantage of them. It seems that wherever people made the switch from hunting and gathering to cultivation, a grass or two lay at the heart of it. The civilizations that followed helped to cement our dependence on grass calories, and those few select species then spread to fields and garden plots around the world. But while historians have long considered the grain diet a relatively recent phenomenon, a product of the agricultural revolution, new thinking puts the seeds of grasses and other plants high on the human menu far into our nomadic, hunter-gatherer past.
    “It’s absolutely reasonable to assume that seeds have been part of the diet forever,” Richard Wrangham told me. “After all, chimpanzees eat them.” As a professor of biological anthropology at Harvard University, Wrangham should know: he published his first paper on chimp feeding habits in the early 1970s, and has been studying them in the wild ever since. I first met Wrangham at a primatologyworkshop in Uganda, where he and Jane Goodall kicked off the keynote address with a piercing exchange of chimpanzee pant-hoots and shrieks. Two decades later, he still knows how to get people’s attention. I called him at his Harvard office, where in spite of pressing research deadlines and a full teaching load, he sounded eager to explain his unorthodox new theory.
    “I used to try and eat what the chimps ate,” he began, recalling his early fieldwork in Uganda’s Kibale Forest, “and I can tell you I was pretty hungry by the end of the day.” At first, Wrangham assumed that he just wasn’t suited to the fruits, nuts, leaves, seeds, and occasional raw monkey that made up the chimpanzee diet. But when he put his observations in the context of human evolution, a profound new idea emerged. It wasn’t the type of food that mattered, but how it was prepared. “I became convinced that we cannot survive in the wild on raw food. As a species, we are entirely dependent on using fire for food preparation. We arethe cooking ape.”
    In spite of his bold ideas, Wrangham speaks carefully, building a case with the patience of someone accustomed to long hours of observation in the field. “My perspective comes from working with apes. I see humans as apes that have been modified,” he explained, noting our substantially smaller teeth, shorter intestines, and larger brains. He told me about the remarkable energy gain achieved through cooking—how roasting or boiling meats, nuts, tubers, and other primate foods increased digestibility by anywhere from a third for wheat and oats to as much as 78 percent for a chicken egg. Wrangham’s theory proposes cooking as the critical innovation separating advanced members of the genus Homo from their more ape-like ancestors. By shifting to a highly digestible, cooked diet, our forebears no longer needed the massive molars and expansive guts that apes need to process fibrous raw foods. And with so much more energy available, we could suddenly afford the metabolic demands of a larger brain.
    Though still controversial, the logic of Wrangham’s thinking rings like a bell tone through the din of competing hypotheses. Traditionally, most anthropologists have emphasized the spear andarrow side of the hunter-gatherer equation, attributing changes in dentition and brain size to better hunting techniques and a protein-rich diet. But Wrangham maintains that no quantity of raw meat (or other raw foods) could adequately nourish modern hominids, let alone spur their evolution. “On a strictly raw diet,” he explained, “you don’t have time for high-risk activities like hunting. If our ancestors ate like chimpanzees, they would have had to spend at least six