Pre-Columbian Roads of the Amazon

By: Clark L. Erickson

Originally Published in 2001

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Traditionally, archaeologists have studied “sites.” Sites include monuments, settle­ments, cities, cemeteries, mounds, and other important places of the past. The cultural land­scape of paths, roads, field walls, irrigation canals, terraces, and other features that fill the spaces between sites is often ignored. A relatively new subfield of anthropology, the ar­chaeology of landscapes, treats the landscape as an artifact that can provide new, detailed in­sights about the everyday lives of peoples of the past. I will focus here on formal roads as an important element of the pre-Columbian land­scape of the Bolivian Amazon.

All civilizations, past and present, require an efficient means of transportation and com­munication. Societies need to move goods, people, and information throughout the regions they control. Roads also have powerful social, political, and sacred functions. Formal roads are major transformations of the environment. Their patterns on the landscape provide infor­mation about the organization of settlements, social interaction, land tenure, ritual, standards of measurement. and the activities of everyday life (Trombold 1990).

The Aztecs. Maya, and Inka constructed im­pressive roads that linked the vast regions under their influence. Less known but equally impres­sive are the pre-Columbian roads in the tropical region of Bolivia, South America (Denevan 1990). I have been investigating the pre-Colum­bian earthworks of the Bolivian Amazon since 1990 (Erickson 1995). The research team in­cludes Wilma Winkler, a Bolivian archaeologist who is co-director of the project, and students from the University of Pennsylvania and the Na­tional University of Bolivia. In 1995, we were invited by the local government to begin a multiyear study of the archaeology of the Baures region. Baures is located along the upper head­waters of the Amazon drainage basin near the Brazilian border in northeast Bolivia (Fig. 2). The area can be reached by boat along a cir­cuitous river route, by horseback, or by small aircraft. The complex landscape of gallery for­ests, crystal clear lakes, rivers, swamps, forest islands, and vast savanna is a spectacular sight from the air (Fig. I). During the rainy season, much of the flat savanna grassland is covered with shallow floodwater. As the rains end at the beginning of the dry season, the floods re­cede and the savanna slowly dries out. At this time, controlled fires rage across the savanna as ranchers and hunters burn the old grass to encourage growth of new grass for their cattle and game. Based on archaeological and histori­cal documentation, I believe that this annual burning is an age-old practice that is necessary to maintain the open savanna. Gallery forests are found along the courses of rivers and streams, and forest islands are located on high ground surrounded by savanna. The native peo­ple practice slash-and-burn agriculture in the gallery forests and forest islands to raise maize, manioc, sweet potatoes, rice, and cacao for mak­ing chocolate, and wealthy ranchers raise cattle on the open savannas.

Early Spanish documents provide valuable information about the Baure, the native peoples of the region. The Jesuits wrote detailed eyewit­ness accounts about all aspects of Baure life in the early 1700s (Eder [1772] 1985). The Jesuits described them as “civilized peoples” who were “clean and tractable” in their fine cotton tunics (Fig. 3). Their chiefs had great powers to make war, mobilize soldiers, keep public order, and organize farming. Anthropologists of the 1950s considered the hereditary political organization of the Baure a classic example of “chiefdom.” Their towns had large public plazas with a large men’s house or temple in the center. Around the plaza were hundreds of houses arranged along streets and wide avenues. Deep defensive moats and tall palisade walls surrounded many settle­ments. In 1703, the Baure gave the Jesuits their first Bolivian martyr, Padre Cipriano Barace, who was killed for insulting a powerful Baure chief. In retaliation, the Spanish sent an army to punish them. In 1708, the remaining conquered Baure were gathered in new mission towns for indoctrination in Christianity and European culture. Crowded into mission towns, the Baure were nearly wiped out by European diseases to which they had little resistance. The population of the region today is probably smaller than in the past.

Reading the Landscape

While exploring for oil in the late 1950s, a North American expatriate named Kenneth Lee discovered and reported the pre-Columbian roads and canals of the Baures region. Until he passed away in 1999, Lee was a determined promoter and interpreter of the archaeology, history, and culture of the region. To show off the huge network of pre-Columbian roads, Lee would fly visiting journalists and scholars over the region in a small plane. As a result, the na­tional and international press rediscovered the “Lost Civilization of Baures” in regular ten-year cycles. Despite this sporadic attention, we were the first archaeologists to do a serious study of the region. The governor of the Department of the Beni loaned us his Cessna airplane for three hours of flight time. Like the previous visitors who flew over the region, we were immediately captivated by the extent, patterning, and size of the roads and other earthworks.

These pre-Columbian roads are raised causeways of earth. Abandoned roads are easily, identified from the air as dark straight lines covered by small trees against the lighter-col­ored grasses of the savanna. The larger roads of Baures can even be seen from satellites orbiting 470 miles above earth. Most of the roads are perfectly straight for several miles and paired parallel roads are common (Fig. 4.). Important questions immediately come to mind: (I) Who built these roads and when? (2) Why were they built? (3) What did they connect?, and (4) Why are there so many roads?

In 1995, my team and I landed on a tiny dirt airstrip in the town of Baures to begin an archaeological investigation to answer these questions. There are no modern towns or settlements in the area of the densest concentra­tion of roads. The only people using the area are hunters who come each year in canoes to hunt the deer, peccaries, and tapirs that thrive in the savannas, wetlands, and forests. I hired three of the best hunters as my guides in 1996.

We used mule, horse, canoe, and what the locals call the buev caballo—an ox saddled for a rider—for the three-day journey into the area (Fig. 5). Most of the trip was on foot sloshing through the wet savanna.

Although abandoned and badly eroded, the roads are still prominent on the landscape. On the ground, we could see that the roads were constructed of earth removed from canals on one or both sides of the platform (Fig. 6). Raised road platforms 10 to 15 feet wide and 2 to 3 feet high provided a dry walking surface (Fig. 7). We assume that the roads were kept clear of vegeta­tion, although shade trees may have lined the wider roads. Roads range in size and complexity from simple to truly monumental. Some raised roads in the savannas t00 miles southwest of Baures are 40 to 60 feet wide. In Baures, we have mapped several roads that are over 3 miles long. Most of the roads are straight from start to finish; thus, we assume that roads were carefully planned before construction. The impressive number of roads, their wide geographical distri­bution, and the effort put into their design and construction suggests that roads were important to the people who built them.

During eight field seasons in the Bolivian Amazon, our archaeological team perfected a strategy for recording and studying roads. They are mapped from the air with aerial photographs and satellite imagery and on the ground using surveying instruments. Long narrow trenches excavated through road platforms and canals provide clues about time of construction and abandonment, building technique, volume of earth moved, and function (see cover). In excavation trenches throughout the Bolivian Amazon, we recovered charcoal that could be radiocarbon dated, documenting that roads were built and used between 2000 and 400 years ago. A date from a causeway excavation in Baures showed that it was built before AD 1630. In the early 18th century. the Jesuits reported that old roads were still in use but not maintained. A 7-mile pre-Columbian road was used between Baures and Guacaraje until the 1930s.

Multi-Functional Earthworks

Roads served many overlapping functions. The tens of thousands of linear miles of roads provided a vast transportation network for foot traffic. The canals alongside them were probably just as important. These canals hold water much of the year thus, heavy loaded dugout canoes could be poled, paddled, or pulled across the sa­vannas. My workers continually complained about having to walk across the hot savanna carrying our heavy gear. They told me to return in the rainy season when they could pole a dugout canoe any­where in the savanna (Fig. 8). The native peoples of this region were a classic example of the “canoe cultures” of the Amazon. Using raised roads for pedestrians and canals for canoe traffic, the Baure had an efficient and sophisticated means of connecting settlements to navigable rivers, ag­ricultural fields, and neighbors.

In other parts of the Bolivian Amazon, raised roads functioned as dikes for controlling flood­ waters within raised fields. (In Expedition 30 [3] 1988, I described a similar raised field farming technique found in the Andes.) In Baures, the roads may have regulated floodwaters, extending the period when canoes could be used in the sa­vannas (Fig. 9). They may also have maintained optimal water levels for the fish weirs built to control and trap fish migrating across the flooded savannas of Baures (Erickson 2000). Further, roads and canals may have been markers to define ownership of farmland and natural resources within and between communities.

In addition to transportation and water management, roads and canals probably had im­portant political functions. Interactions between Amazonian communities are characterized in the historical and ethnographic literature as a complex and dynamic balance between alliance and warfare. Highly visible earthworks may have been used to establish and cement political alliances with neighboring communities. Most roads connect pre-Columbian settlements lo­cated on forest islands within the savannas and gallery forests on rivers. We can safely assume that settlements physically connected by arti­ficial roads and canals were part of a larger political universe. We located several concentra tions of roads associated with large settlements on forest islands. Between 10-50 roads and ca­noe paths converge on or radiate from each large island (Fig. t0). These roads can be fol­lowed to archaeological sites on smaller forest islands distributed over the landscape. Each of these interconnected concentrations of roads may represent an independent political, social, or ethnic group.

Symbols of Civic Pride or Ritual Raceways?

But why did the Baure build so many fine roads? My colleagues joke that every individual must have had his or her own road. The Baure had no draft animals or wheeled vehicles, thus they had little need for wide straight roads.

Landscape archaeologists refer to roads that are much larger, straighter, or more numerous than what would have been necessary for basic transportation as “overconstructed,” “overengi­neered,” and “landscape oblivious.” However, I believe these roads were conspicuous symbols of a community’s political power, civic pride, and ability to mobilize labor. Rather than construct permanent public buildings, shrines, cities, or temples in stone, the pre-Columbian peoples of the Bolivian Amazon expressed monumentality in the form of prominent earthworks on the vast flat landscape. Guests attending feasts, pil­grimages, dances, and other events must have been suitably awed when approaching neigh­boring villages and towns on the wide avenues bordered by deep water-filled canals (Fig. ii). Competition between communities for the largest, widest, longest, straightest, and most impressive roads may help account for the em­phasis on these earthworks. The social use of roads is specifically mentioned in the 1772 Jesuit account. Father Eder complained that the native peoples used roads for social visits with friends in neighboring villages, the sole purpose of which was to get drunk on the local beer brewed from maize and manioc!

In addition, the earthworks may have had specific sacred functions. As noted earlier, the roads are extraordinarily straight over long dis­tances. As many as six canals and roads may run parallel to each other—a costly mismanagement of labor if the roads were constructed simply to get from Point A to Point B. Of course, we could argue that the roads were one-way streets, thus two were necessary for a round trip. Could the concern with precision and straightness be re­lated to ritual processions, ceremonial races, or pilgrimage routes? Could the roads be sacred or astronomical alignments? Some straight roads in Baures bypass forest islands and have no apparent destination. The similarity between the roads of Baures and the famous Nasca Lines etched on the coastal deserts of Peru comes to mind. Scholars have demonstrated that some Nasca Lines were used for ritual processions and determining as­tronomical events, and as indicators of sources of water and markers of social groups (Aveni 2000). We have begun to map and measure the orientations of the roads of the Bolivian Amazon to test the hypothesis that roads were constructed according to astronomical alignments or as a giant landscape calendar.

Roads may have converged on political cen­ters or sacred sites. Early Spanish explorers reported entering towns on large formal roads. The larger towns of Baures had hundreds of houses organized around a large open plaza with public buildings and temples in the center. The indigenous peoples of central Brazil still live in similar, although much smaller, villages. Clean, wide straight roads cut through the forest and converge at the men’s house in the center of the plaza. During important ceremonies, young men carrying heavy logs race each other along these ritual roads. Many important roads are deeply furrowed by years of use for ritual processions and racing.

How Were the Roads Built?

How difficult are roads to construct? The roads of the Bolivian Amazon are major, formally designed features of the built en­vironment. Archaeologists often attribute the construction and use of formal roads to cen­tralized state governments (Trombold 1990). This conclusion is based on the assumption that the labor organization and engineering for constructing roads were beyond the abilities of small-scale societies. The total labor involved in pre-Columbian earthmoving in the Bolivian Amazon is staggering, but our archaeological, re­search shows that the work was spread out over many generations and could have been accom­plished by small groups.

Although roads are often long and straight, the engineering and design of these earthworks are not complicated. The roads were built using simple tools of hardwood such as digging sticks, paddle-like shovels, and baskets documented in the historical literature. Similar tools are still used today for digging and moving earth, al­though the blades are now of metal. Our earlier experiments building raised fields showed that digging canals and constructing platforms is rel­atively easy if done at the time when soils are neither too wet or too dry.

These issues of engineering and organiza­tion of labor became clear one day while doing fieldwork near a native village in Baures. I came across a “new” road 12 feet wide, 3 feet high, and over a half mile long (Fig. 12). When I asked a local resident walking about it with me, he explained that he and a small group of neighbors built it in a week. I asked, “How did they make the road so straight?” He rolled his eyes at the silly question and said, “We simply sighted along three wooden poles to lay out a direct route be­tween the settlements. Anyone can do it.” This modern example of the design and construction of roads by a community using hand tools dem­onstrates that many small groups working a few weeks a year could have easily constructed the entire road system given enough time.

I believe that roads and other earthworks were the Amazonian version of monumental, highly visible public construction. The mon­umentality of this engineered landscape at a regional scale rivals the works of better-known civilizations. Although most are abandoned, eroded, and neglected, the old roads, canals, and other earthworks continue to play a major role in shaping the landscape of the Bolivian Ama­zon. Pre-Columbian roads structure patterns of vegetation, soil fertility, water availability, and wild resources. Through their transformation of nature on a massive regional scale, the pre-Co­lumbian inhabitants of the Bolivian Amazon left an indelible mark on the landscape.


The author thanks Wilma Winkler (co-in­vestigator of the project), Kenneth Lee, Ricardo Bottega, Anita and Edwin Bruckner, Conrad Bruckner, Hans Schlink, Oswaldo Rivera, and local government authorities who made this research possible. Wilma Winkler, Dr. Alexei Vranich, Dr. John Walker, Dr. Kay Candler, and Dante Angelo made up the archaeological team. Dr. Alexei Vranich, Freddy Bruckner, and Oscar Saavedra did the first archaeological research of the Baures roads in 1995. Grants from NSF, the Heinz Charitable Trust Foundation, the Amer­ican Philosophical Society, Research Funds of the University of Pennsylvania Museum, and CORDEBENI supported fieldwork and analysis.

Cite This Article

Erickson, Clark L.. "Pre-Columbian Roads of the Amazon." Expedition Magazine 43, no. 2 (July, 2001): -. Accessed February 25, 2024.

This digitized article is presented here as a historical reference and may not reflect the current views of the Penn Museum.

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