A publication of the Archaeological Institute of America
The traditional view of the adoption of agriculture in the southwest United States and northwest Mexico may be too simple, according to Robert J. Hard, of the University of Texas, San Antonio, and John R. Roney, of the Bureau of Land Management. Archaeologists have believed that it was a uniform process in which mobile hunting-gathering bands passed through a gradual transition involving casual cultivation of maize and other crops before they became fully sedentary village dwellers dependent on farming at about A.D. 500. Based on their excavations at Cerro Juanaqueña, in northwestern Chihuahua, south of the New Mexico border, and other recent discoveries, Hard and Roney think the transition was much more variable. Located on a hilltop overlooking the floodplain of the Río Casas Grandes, Cerro Juanaqueña covers about ten acres. It is conspicuous for its terraces, some 468 of them averaging 58 feet long and 23 feet wide. Such terraces are common at sites in the region, but archaeologists have debated whether they were used as agricultural plots or as settlements with farming taking place elsewhere. At Cerro Juanaqueña, Hard and Roney found discarded grinding stones, animal bones, ash, and other domestic refuse suggesting that the terraces had been used for habitation. They estimate that construction of the site's terrace walls, more than five miles long in all, would have required the movement of some 22,000 tons of earth and basalt cobbles.
The site's inhabitants ate jack rabbit, cottontail rabbit, mule deer, and pronghorn antelope along with maize, wild squash, and seeds of wild plants. None of this data would, on its own, upset the old view of the adoption of agriculture. But radiocarbon dates from charred maize and wild squash fragments from the site indicate that it was inhabited about 1000 B.C., a millennium or more earlier than other such large settlements. At this early date maize was only just being introduced over most of Arizona and New Mexico, and settlements were limited to a few small houses or rockshelters, although some larger settlements have been found in Tucson, Arizona.
Cerro Juanaqueña may also challenge another long-established notion. Throughout southwestern prehistory the inhabitants of large villages farmed substantial quantities of maize as the deserts did not naturally produce enough wild food for a large stationary population. Hard and Roney, working with ethnobotanists Karen Adams of Crow Canyon and Gayle Fritz of Washington University have recovered from Cerro Juanaqueña far more charred seeds from wild plants such as nondomesticated squash, grasses, and weedy species than maize. In addition, the size of the grinding stones suggests small-seeded local plants were used more than maize. The scientists are considering the possibility that maize was not the staple and instead the inhabitants may have been cultivating some local plants, typically thought of as weeds, including amaranth and purslane as well as grasses. Historically known Native Americans in California and the southwest were known to have tended such plants to enhance their productivity. The link between substantial dependence on maize and the establishment of large villages may therefore not hold true for Cerro Juanaqueña although more research is required in this area.
Elsewhere, Hard and Roney note, there appear to be other exceptions to the traditional belief in a uniform transition to maize agriculture and the formation of settled village life. For example, at Black Mesa, in northern Arizona, and Cedar Mesa, in southern Utah, evidence for substantial use of maize is present at small settlements of a few pithouses and in rockshelters by 2,000 years ago, a millennium after the occupation of Cerro Juanaquena. However, maize was only a minor part of the diet until about A.D. 1100 in south-central New Mexico and western Texas, although those Native Americans lived in villages with more pithouses. The evidence from Cerro Juanqueña and elsewhere in the region, contend Hard and Roney, indicates considerable variation in the timing of dependence on intensive maize agriculture and the formation of large villages.
The excavations at Cerro Juanaqueña have been funded by the National Science Foundation and supported by the Instituto Nacional de Antropología e Historia.