Pre-Classic and Classic periods
Early hunters (to 6500 bce)
The time of the first peopling of Mesoamerica remains a puzzle, as it does for that of the New World in general. Until recently it was widely accepted that groups of peoples entered the hemisphere from northeastern Siberia, perhaps by a land bridge that then existed, at some time in the Late Pleistocene, or Ice Age. But radiocarbon dating and other relatively recent tools have complicated the story. Perhaps they entered the West Coast from the sea at multiple points. There is abundant evidence that, at least by 11,000 bce, hunting peoples had occupied most of the New World south of the glacial ice cap covering northern North America. These peoples hunted such large grazing mammals as mammoth, mastodon, horse, and camel, armed with spears to which were attached finely made, bifacially chipped points of stone. Finds in Mesoamerica, however, confirm the existence of a “prebifacial-point horizon,” a stage known to have existed elsewhere in the Americas, and suggest that it is of very great age. In 1967 archaeologists working at the site of Tlapacoya, southeast of Mexico City, uncovered a well-made blade of obsidian associated with a radiocarbon date of about 21,000 bce. Near Puebla, Mexico, excavations in the Valsequillo region revealed cultural remains of human groups that were hunting mammoth and other extinct animals, along with unifacially worked points, scrapers, perforators, burins, and knives. A date of about 21,800 bce has been suggested for the Valsequillo finds.
More substantial information on Late Pleistocene occupations of Mesoamerica comes from excavations near Tepexpan, northeast of Mexico City. The excavated skeletons of two mammoths showed that these beasts had been killed with spears fitted with lancelike stone points and had been butchered on the spot. A possible date of about 8000 bce has been suggested for the two mammoth kills. In the same geologic layer as the slaughtered mammoths was found a human skeleton; this Tepexpan “man” has been shown to be female and rather a typical American Indian of modern form. While the association with the mammoths was first questioned, fluorine tests have proved them to be contemporary.
The environment of these earliest Mesoamericans was quite different from that existing today, for volcanoes were then extremely active, covering thousands of square miles with ashes. Temperatures were substantially lower, and local glaciers formed on the highest peaks. Conditions were ideal for the large herds of grazing mammals that roamed Mesoamerica, especially in the highland valleys, much of which consisted of cool, wet grasslands not unlike the plains of the northern United States. All of this changed around 7000 bce, when worldwide temperatures rose and the great ice sheets of northern latitudes began their final retreat. This brought to an end the successful hunting way of life that had been followed by Mesoamericans, although humans probably also played a role in bringing about the extinction of the large game animals.
Incipient agriculture (6500–1500 bce)
The most crucial event in the prehistory of Mesoamerica was the human capture of the food energy contained in plants. This process centred on three plants: Indian corn (maize), beans, and squashes. Since about 90 percent of all food calories in the diet of Mesoamericans eventually came from corn, archaeologists for a long time have sought the origins of this plant—which has no wild forms existing today—in order to throw light on the agricultural basis of Mesoamerican civilization.
The search for Mesoamerican agricultural origins has been carried forward most successfully through excavations in dry caves and rock shelters in the modern southern Mexican states of Puebla and Oaxaca. Sequences from these archaeological sites show a gradual transition from the Early Hunting to the Incipient Cultivation periods. At the Guila Naquitz cave, in Oaxaca, there are indications that the transition began as early as 8900 bce; finds from caves in the Tehuacán valley of Puebla, however, offer more substantial evidence of the beginnings of plant domestication at a somewhat later time. There, the preservation of plant remains is remarkably good, and from these it is evident that shortly after 6500 bce the inhabitants of the valley were selecting and planting seeds of chili peppers, cotton, and one kind of squash. Most importantly, between 5000 and 3500 bce they were beginning to plant mutant forms of corn that already were showing signs of the husks characteristic of domestic corn.
One of the problems complicating this question of the beginnings of early corn cultivation is related to a debate between paleobotanists on wild versus domesticated strains. One school of thought holds that the domesticated races of the plant developed from a wild ancestor. The other opinion is that there was never such a thing as wild corn, that instead corn (Zea mays) developed from a related grass, teosinte (Zea mexicana or Euchlaena mexicana). In any event, by 5000 bce corn was present and being used as a food, and between 2,000 and 3,000 years after that it had developed rapidly as a food plant. It has been estimated that there is more energy present in a single kernel of some modern races than there was in an ear of this ancient Tehuacán corn. Possibly some of this was popped, but a new element in food preparation is seen in the metates (querns) and manos (handstones) that were used to grind the corn into meal or dough.
Beans appeared after 3500 bce, along with a much improved race of corn. This enormous increase in the amount of plant food available was accompanied by a remarkable shift in settlement pattern. In place of the temporary hunting camps and rock shelters, which were occupied only seasonally by small bands, semipermanent villages of pit houses were constructed on the valley floor. Increasing sedentariness is also to be seen in the remarkable bowls and globular jars painstakingly pecked from stone, for pottery was as yet unknown in Mesoamerica.
In the centuries between 3500 and 1500 bce, plant domestication began in what had been hunting-gathering contexts, as on the Pacific coast of Chiapas and on the Veracruz Gulf coast and in some lacustrine settings in the Valley of Mexico. It seems probable that early domesticated plants from such places as the Tehuacán valley were carried to these new environmental niches. In many cases, this shift of habitat resulted in genetic improvements in the food plants.
Pottery, which is a good index to the degree of permanence of a settlement (because of its fragility it is difficult to transport), was made in the Tehuacán valley by 2300 bce. Fired clay vessels were made as early as 4000 bce in Ecuador and Colombia, and it is probable that the idea of their manufacture gradually diffused north to the increasingly sedentary peoples of Mesoamerica.
The picture, then, is one of growing human control over the environment through the domestication of plants; animals played a very minor role in this process, with only the dog being surely domesticated before 1500 bce. At any rate, by 1500 bce the stage was set for the adoption of a fully settled life, with many of the sedentary arts already present. The final step was taken only when native agriculture in certain especially favoured subregions became sufficiently effective to allow year-round settlement of villages.