The Anasazi from A.D. 700 to A.D. 900

Pueblo I (A.D. 750 - 900) is a cultural period during one of the worst climatic episodes on the Colorado Plateau. In addition to a rapid decrease in effective moisture, there was also significant erosion, depressed water tables, and high seasonal and year-to-year variability in rainfall. These poor conditions no doubt contributed to substantial changes in Anasazi population distribution. Some marginal areas experienced a decrease in population densities and related abandonments, while other areas, especially arable lands along major drainages, saw rapid growth.

Anasazi groups in different part of the Colorado Plateau responded to the conditions of Pueblo I in unique ways. Accordingly, archaeologists often divide the Anasazi into several "sub-groups" depending on where they lived, which affected how much they focused on agricultural pursuits, what their villages looked like, and how they interacted with one another. Some groups, such as the Virgin Anasazi of northwestern Arizona and southeastern Utah, always depended on a large proportion of wild foods in their diet and they were more mobile than other Anasazi groups. In contrast, the Chaco Anasazi living in what is now northwestern New Mexico appear to have been more sedentary and focused more heavily on maize agriculture. Because of all this variability in the ways that the Anasazi adapted to different environments, the following description of Anasazi life in Pueblo I is a generalization.

Most occupants of the Colorado Plateau became dependent on agriculture during Pueblo I. Probably because of the poor environmental conditions, Anasazi farming techniques were generally conservative, focused on "dry farming" (i.e., reliant only on rainfall), as was the choice of cultigens planted (i.e., no new plants were domesticated or borrowed from Mesoamerica during this period). Apparently, people felt that they could not afford to take chances during this period. Most Anasazi groups were also almost fully sedentary, although household and village abandonments no doubt occurred frequently in response to changing climatic factors, human-induced deforestation, overuse of agricultural lands, or changing social and political contexts. Several studies have shown that the average Anasazi habitation was occupied for only 30-50 years, but this varied in different parts of the Colorado Plateau. As an example of one extreme, extensive research on Black Mesa in Arizona has suggested that people were much more mobile there than people living in other nearby areas, perhaps moving to different areas according to what resources were seasonally available. Accordingly, these Anasazi appear to have had separate houses, one for summer and one for winter.

Within this context, some of the most intriguing changes in Anasazi material culture revolved around both domestic and ritual architecture. As Pueblo I advanced, pithouses became deeper and began to exhibit features resembling those found in later ceremonial kivas. For example, many pithouses had a ventilator instead of an antechamber and occasionally contained a small hole in the floor that in historic times was known as a sipapu, or symbolic entrance to the spiritual world. However, despite these arguably ceremonial features, many scholars believe that most pithouses were probably still used for domestic activities. The evidence also suggests that many pithouses were only inhabited during certain seasons. Pitstructures with ceremonial features are often referred to as "protokivas" due to their ambiguous nature, halfway between fully domestic structures and ceremonial architecture.

Pueblo I also saw the appearance of surface architecture that supplemented earlier pithouse forms. The surface rooms were typically built as a single-story arc behind the protokiva, forming what is often known as the "Prudden unit pueblo," named after archaeologist T. M. Prudden. Above-ground architecture appears to have been originally used for storage, probably for surplus foods that were used as a buffer against year-to-year variability in crop success. However, this row of rooms was soon expanded to include domestic quarters, while the protokiva continued to exhibit both domestic and ceremonial features. Pueblo I communities consisted of concentrations of these roomblocks and were often accompanied by one or more oversized pit structures that were much larger than the smaller protokivas. In an analysis of pottery from oversized pithouses in southwestern Colorado, archaeologist Eric Blinman found that ceramics associated with these structures indicated that they were the locus of ceremonial "potluck" gatherings and exchange activities.

The smallest Anasazi communities were likely inhabited by a number of closely related people who would cooperate in farming activities, share food surpluses, and contribute to important rituals. However, the research of archaeologists such as Cynthia Bettison have identified some Pueblo I villages in which more and more people were aggregating in larger and larger villages. For example, Bettison found ninth-century villages in the Zuni River valley in which numerous individual residences, each likely representing a family, were clustered closely together. These large aggregations of increasingly unrelated people would have presented new challenges to the Anasazi.

As Pueblo I populations grew, evidence for transitory positions of authority-based leadership emerges in some communities in the form of different house sizes and access to valuables. There is also more evidence that people were increasingly concerned about protecting their property. For example, archaeologists Wirt Wills and Tom Windes found that, starting in Basketmaker times, storage areas were increasingly protected from public access, while Tim Kohler has suggested that the presence of small fieldhouses placed in agricultural fields shows that private control of land and the associated desire to defend one's crops were developing. Fred Plog has argued that Pueblo I is a period during which many Anasazi communities invested a considerable amount of effort in forming alliances with neighbors. These alliances were arguably based on the sharing of food surpluses as well as the exchange of valuables, but Plog also believed that these alliances contributed to the social differentiation and political complexity that are more clearly exhibited by the Anasazi in later periods.