Dr. Adrián Oyaneder from the University of Exeter used publicly available satellite data to examine a 4,600 square-kilometer area of the Camarones River Basin, focusing on upland regions that had previously received little archaeological attention. Over four months of analysis, he identified numerous sites of archaeological interest, with results published in the journal Antiquity. The research challenges long-held assumptions about the timeline of subsistence transitions in South American highland communities.
The V-shaped hunting traps, known as chacus, were used by various Andean communities to funnel prey, particularly vicuña - wild relatives of the alpaca. These findings indicate that hunting and foraging remained major aspects of life long after researchers believed people had transitioned to agropastoralist farming around AD 650, suggesting these practices may have coexisted with herding and pastoralism rather than being replaced by them.
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Aerial photograph of two chacu hunting traps. (A. Oyaneder/Antiquity Publications Ltd)
Sophisticated Stone Trap Architecture
The 76 stone chacus discovered represent an unprecedented concentration of such structures in the Andes region. Similar hunting traps have been found in other arid regions worldwide, including the Middle East, but this marks the first time such a large number has been documented in this area. The discovery raises intriguing possibilities that these structures may predate those known to have been used by the Inka.
Most of the chacus follow a distinctive V-shaped design formed by two "antennae" constructed from dry-stone walls. These walls average approximately 1.5 meters in height and 150 meters in length, funneling down to enclosed areas of roughly 95 square meters. The enclosures were dug or established to depths of around two meters - sufficient to trap any animals driven into them by hunters working cooperatively across the landscape.
All the chacus were strategically positioned on steep slopes pointing downhill, with some incorporating natural topographical features to create one of the antenna walls. Significantly, they were located at altitudes within the usual range of the vicuña, demonstrating sophisticated understanding of animal behavior and habitat preferences.
Diagram illustrating the funnel mechanism that directed vicuña into capture areas. (A. Oyaneder/Antiquity Publications Ltd)
Evidence of Persistent Settlement Networks
Dr. Oyaneder's survey revealed almost 800 small-scale settlements distributed across the study area, ranging from single buildings covering no more than one square meter to complexes containing nine or more structures. Using Geographic Information Systems (GIS), these settlements were grouped into likely clusters linked to nearby chacus and other habitation sites, all within 5-kilometer distances of each other.
"There has long been a discrepancy between what archaeological and ethnohistorical records have told us about life in the Western Valleys of northern Chile during the colonial period," explained Dr. Oyaneder.
Archaeological research has pointed to a gradual decline in hunting and gathering from 2,000 BC onwards with the introduction of domesticated plants and animals. However, historical sources such as Spanish tax records from the 16th to 19th centuries refer to 'Uru' or 'Uro' - a generic term for foraging populations who were of little economic interest to the colonizers.
"My reaction when I saw the first chacu was to double and even triple check it," Dr. Oyaneder recalled.
"Initially, I thought it was a unique occurrence, but as I progressed with my survey, I realized they were everywhere in the highlands and in a quantity never previously recorded in the Andes."
Examples of chacu traps found in the Camarones Basin. Note the drop found in the trap shown in the middle. (Oyaneder/Antiquity Publications Ltd)
Redefining Andean Subsistence Strategies
The research revealed fascinating historical connections when Dr. Oyaneder discovered references to choquela - specialized vicuña hunting groups - in academic literature by researchers Thérèse Bouysse-Cassagne and Olivia Harris. These sources contained specific terminology referring to chacu hunting people and chacu hunters, providing ethnographic context for the archaeological discoveries.
"The picture that emerges is of a landscape occupied by a range of human groups from at least 6000 BC to the 18th century," Dr. Oyaneder concludes. "These groups moved strategically across the highlands, tethered primarily to hunting resources, particularly vicuña. The evidence indicates overlapping lifeways, combining hunting-gathering with agropastoral practices, and a network of short-term seasonal settlements and outposts to help people move across rugged and difficult terrain."
This discovery fundamentally challenges traditional archaeological models that suggested a linear progression from hunting-gathering to agricultural societies. Instead, it reveals sophisticated mixed economies that allowed communities to maximize resource security across challenging highland environments for thousands of years.
Top image: Aerial photograph revealing V-shaped chacu hunting trap structures used by ancient Andean communities. Inset; Wild vicuna roaming. Source: A. Oyaneder/Antiquity Publications Ltd Inset; gustavo/Adobe Stock
By Gary Manners
References
Oyaneder, A. 2025. A tethered hunting and mobility landscape in the Andean highlands of the Western Valleys, northern Chile. Available at: https://doi.org/10.15184/aqy.2025.10213
