Why did the Lower Pecos culture spread deeply into northern Mexico and not westward into the Three Rivers area of New Mexico or eastward into the Three Rivers area of Texas?

Please keep in mind that the following is largely conjectural on my part but the conjecture was germinated from some hard data. I am also here going to respond as though the expansion of culture was the result of the actual movement of people, which may not be the case. It is quite possible that ideas were transmitted by contact along the perimeter of the cultural area, thus accounting for the differences within the same art style, south and north of the river. These points can only be resolved when we have a better handle on the dates of the various pictographs and other features and considerably more work has been done in Mexico. (Remember - only two archeological sites have been excavated in northern Coahuila as opposed to the dozens in the Lower Pecos). Although we are still not sure of the extent of the Lower Pecos cultural area at various points in time, during the Middle Archaic period when the Pecos River style art seems to have reached its peak, it appears that there were climatic pressures that encouraged people to concentrate on the three major rivers - the Rio Grande, Pecos and Devils (as opposed to Three Rivers, New Mexico and Three Rivers, Texas).

My hypothesis is that the concentration of people created new, more stressful situations that in turn produced ritual behavior that increased communication and reduced conflict, ergo the Pecos River style as public information system. The constriction of territories and the regionalization of cultural traits is seen in other areas during the Middle Archaic period so we can assume there were broad underlying reasons that affected much of Texas and adjoining areas. West Texas presented large stretches of waterless desert and following the Rio Grande was no easy proposition. People tended to huddle near the home water hole, elaborating their cultural environment to cope with stresses imposed by nature. Subsequently, a break in the drying trend - a wetter, cooler interlude - promoted a change in vegetation, allowed the bison to reenter the southern Plains as far as northern Mexico, and attracted the traditional hunters from the Plains. This transition, of course, took place over decades and centuries, not years. During this time, the Lower Pecos people, who were desert adapted cave dwellers may well have retreated southward, sticking with the environment they knew best as well as getting out of the way of the more mobile hunting people.

The mountains of northern Mexico can be seen from the Rio Grande and by their very presence undoubtedly attracted the more venturesome throughout prehistory so they were not an unknown - or at least as unknown as the arid regions to the east and west. The springs, such as La Babia, San Vicente, Acatita - later shown to Spaniards and their guides, were undoubtedly familiar to the native people that came long before them. Remembering that there were already people - and probably people only distantly related to the Pecos folks - already entrenched in areas north, east, and west of the Pecos - politically the logical direction to spread was south to a known rather than an unknown. Although some of their artifact classes point to transitional cultural zones between the mountain and canyon people, others show striking similarities, including the Pecos River style paintings. Thus we have familiarity and probably genetic and social ties that span the relatively short distance between the river and the mountains. So there were ideological, economic, and political advantages in moving south that were not there north, west, or east. Social anthropologists have noted that there is a general trend toward southerly-northerly movements in human land migrations anyway and we can see that trend is still operating today. (Of course this trend was totally controverted by such dramatic events as the discovery of the New World, gold strikes in California, and now by jet travel).

Later in time, with the return to aridity and the retreat of the Plains environment, it is quite possible that the desert adapted people returned to the Lower Pecos - but without their monumental rock art. The Late Archaic period sees considerable movement of people, goods, and ideas in neighboring cultural areas but this fluidity reaches its peak in the Late Prehistoric period, after the introduction of the bow and arrow. It is then that we see connections between the Big Bend and the Lower Pecos in the Red Monochrome art as well as in a number of other introduced traits. By now, however, there were strong cultures well established in surrounding areas and, although few of them were interested in taking over the Lower Pecos with its highly specialized desert economy, they were equally unlikely to welcome immigration by people with little to offer in terms of trade goods or technology. Although we see broad similarities consistent with shamanistic religious practices in rock art throughout the Southwest and Texas, they probably had doctrinal differences about as significant as those between Lutherans and Methodists, much less between Catholics and Moslem. This brings us back to the issue of layers of culture that we discussed in an earlier newsletter - basic similarities in the long term evolution of culture that are overlain by variations that are elevated to great importance in the short span of human life and memory.