Some sociobiologists argue that an impulse toward violence is written in our genes, but archaeologist Joyce Marcus sees a more modern origin for war in the charred remains of old stockades in Oaxaca, Mexico.
Marcus and her colleague Kent Flannery, both at the University of Michigan Museum of Anthropology, carbon-dated relics from a string of sites in Oaxaca. The oldest evidence of war came from a village called San José Mogote, where Marcus and Flannery found a double line of 3,260-year-old burnt postholes, the remains of a palisade probably built to defend the village from raiders. Over the next 800 years, such forays apparently escalated into all-out war. A 2,580-year-old carved stone from the site depicts the corpse of a captive chief whose heart had been excised. By 450 B.C. the villagers had relocated to the top of a fortified peak called Monte Albán, from where they launched campaigns of conquest against surrounding settlements.
Marcus believes that social factors explain much of this drive toward war. Small itinerant families—the original inhabitants of the area—could not accumulate much food, so there was little potential for collective conflict. It was only when people amassed enough resources to form guilds and build storehouses that groups began to attack others and build defenses. “Warfare does have a beginning,” Marcus says. “It wasn’t always there. It’s by no means inevitable.”