Archeologists have studied the U.S. Southwest and northwest Mexico for more than a century. But recent discoveries have rewritten its prehistory. Researchers once believed hunting and gathering were the sole means of subsistence until the early centuries AD. Now, it's clear farming was part of Indigenous life here for more than 5,000 years.
One transformative find came in our region. In “Early Farming and Warfare in Northwest Mexico,” Robert Hard and John Roney summarize their research at Cerro Juanaqueña, a monumental hilltop site near Janos, Chihuahua. As their title suggests, the emergence of Chihuahuan Desert farming societies seems to have had a dark side.
One-hundred-thirty miles west of El Paso, Cerro Juanaqueña rises above a landscape that could be mistaken for the Marfa Plateau. Atop this hill, a 5-mile network of terraces was built around 1300 BC, by people who farmed corn, and perhaps amaranth. The discovery of the site was a revelation. No one had suspected that such farming, or such large-scale construction, had existed in our region's deep past. And other such terraced hills were discovered nearby.
Terrace-building required great labor. But Cerro Juanaqueña's people farmed the nearby Rio Casas Grandes floodplain, not the terraces. Which raised a big question, Hard said.
“What are they doing on these terraces?” he said. “So we paid a lot of attention to the material culture we were finding on the terraces. In a lot of cases we'd find trash deposits – evidence people had been living there. And then we found over a hundred rock rings. And the rock rings are the foundations of small houses, small structures.”
Hearths and metates, debris from cooking and stone-tool making – the evidence showed this was not a site for periodic gatherings, but a place where people lived.
And why would they live there? A hilltop home might be a status symbol today, but for ancient people it would have been no small matter to carry up water, firewood and other necessities each day.
For insight, Roney and Hard turned to the Human Relations Area Files, a database that codes vast stores of ethnographic knowledge about the world's traditional cultures. They learned there are two primary reasons traditional societies build hilltop communities: the terrain leaves no other option, or the community is defending itself.
Other lines of evidence reinforced the second possibility. Cerro Juanaqueña provides a 360-degree view – no one could approach undetected. And its stone walls would have slowed would-be attackers. The site, the scientists concluded, was a fortified village.
“The typical form of warfare in that time period, as we envision it,” Roney said, “would be a surprise attack, where the attackers try to overrun village. In this kind of setting it would be impossible to do that, because of its setting on the hill, and also because attackers would have to be paying a lot of attention to where they put their feet as they ran toward the defenders.”
The nature of that warfare remains a mystery. But developments here weren't occurring in isolation. Farming societies were emerging nearby, at other desert oases – in present-day Sonora, Mexico, and along Arizona's Gila River. Roney and Hard suspect that conflict erupted between these societies, as they competed for resources, or status.
Cerro Juanaqueña was likely occupied by about 200 people. Around 1100 BC, it was abandoned. Climatic changes may have strained farming. Or perhaps violence ceased, and fortified villages were unnecessary.
Many questions remain. But one thing is clear: farming societies, and the explosive politics that often accompany such societies, have a much longer history here than archeologists ever imagined.
