Ruled from Mexico City for about a century longer than they have thus far been from Washington, New Mexico and Arizona lie in what English speakers generally term ‘the Southwest’. I follow that usage here, even though calling them the ‘Northwest’ (of first colonial New Spain and then an independent Mexico) would, for this chapter’s purposes, be more accurate, as well as emphasizing that the cultural area to which their Indigenous inhabitants belonged extended across modern Chihuahua, Coahuila, Durango, Sinaloa, and Sonora. Together with the Southern Plains, to which trade links intimately tied it before and after Spanish arrival, the Southwest constituted the cradle within which the first Horse Nations of North America took shape. I start by highlighting key aspects of the two regions’ ecologies and prehistories. Next, I look at the horse’s impact on the Southwest’s settled farming peoples, particularly the Pueblos, many of whom came under Spanish rule after 1598. Its take-up by their Athapaskan-speaking neighbours, the Apache and Navajo, gives us our first view of how more mobile societies understood and used the horse, including—in the Navajo case—the development of a distinctive pastoralist way of life. Attention then turns to the Comanche, another pivotal player in the horse’s expansion across western North America, for whom it altered not just how they secured food, but also their social organization and entire economy. Trade—especially trade in horses—was critical in this, and so I end by examining the horse’s arrival among some of the Comanches’ trade partners, the village communities of the eastern edge of the Southern Plains, an area to which Native farmers-with-horses from the American South moved, and were forced to move, in the early 1800s. The Southwest is one of the driest parts of North America (Plate 4). Its climate is also strongly seasonal, with cold winters and hot summers. Major drainages are few: the Colorado in the west and northwest, southern Arizona’s Gila, the Río Grande, which snakes south through New Mexico and then along the present Texas/Mexico border, and the rivers draining into the Gulf of California from Mexico’s rugged Sierra Madre Occidental.
Mechanisms of Seasonal Soil Moisture Drought Onset and Termination in the Southern Great Plains