The transport of goods over distances that exceed immediate complementarity relationships in mountain environments is well-documented archaeologically and ethnographically in the south-central Andes. Point specific resources like obsidian and salt have a distinctive, radiating distribution pattern as compared with subsistence exchange between ecological zones (Figure 3-4). Mechanisms that include direct acquisition and down-the-line exchange (boundary reciprocity) are likely to have been long-term exchange modes that served to disseminate of goods horizontally through a single ecological setting like the Andean altiplano. However, it is known ethnohistorically that long distance transport with the aid of camelid caravans, either with direct procurement and including very few transfers (long distance trade caravans), was a common method for the lateral distribution of goods. When did long distance caravan transport begin to dominate regional exchange in the south-central Andes, and who initiated this form of transfer between far-flung populations? Principal factors that influence the origin and perpetuation of long distance trade routes by highland pastoralists in the south-central Andes include the following features.

(1) Cargo animals:While not exceptionally strong, llamas are effective cargo animals because they are relatively compliant, they are not water tethered, and they can consume a range of grasses found on the altiplano so that they do not have to transport their own fodder.

(2) Topography:By virtue of the open and predominantly low-angle topography of the altiplano, the movement of loaded cargo animals across the altiplano requires lower effort than travel along the eastern or western sierra that are bisected by deep valleys.

(3) Resources:On an inter-regional scale, the altiplano divides complementary resource areas from the Amazon lowlands to the Pacific Ocean and these converged on the altiplano during particular time periods.

These features created circumstances that allowed for the wide-distribution of materials like obsidian and other products in the south-central Andean highlands. Long distance exchange and spatial relationships have been presented as a primary factors in the appearance of early social complexity during the Middle and Late Formative (Bandy 2005;Stanish 2003: 159-164). However, given the antiquity of camelid domestication in the Andes the long distance caravan pattern probably predated the Middle Formative by a millennium or more. The presence of caravans and the transport of complementary goods around the high, flat altiplano are part of a number of characteristics that created the circumstances within which social inequalities evolved. Competition for social power emerged during the Formative from a context that included these features of long distance exchange both in terms of the capacity for regional interaction, and the social institutions that surrounded the organization and scheduling of exchange in the region. These regional exchange mechanisms had long term consequences based the theory of Clark and Blake (1994: 17) who argue that social ranking was the unintended outcome of early political actors, operating within the institutional constraints of their circumstances, pursuing short term prestige goals for themselves and for their supporters. Following this model, the established circulation mechanisms of non-local products during the Early Formative, and perhaps earlier, are likely to have had a significant influence on the strategies pursued by aggrandizers during subsequent periods such as the Middle Formative.