Puerto Rico's ancient past unveiled: Oldest human remains date back to 1800 BC

The mortuary procedures – such as the placement of the bodies and the grave objects that accompany them – are comparable to those at other early sites, demonstrating common burial customs through many years. Furthermore, a strontium isotope study reveals that those buried were born in several adjacent locations. As a result, the Ortiz site may have had cultural significance as a gathering place for surrounding people to conduct funerals.

Significance of the results

The results suggest a long history of sustained and institutionalized use of a commonplace across millennia, while the authors advise that general inferences should be avoided given the low amount of available data.

Traditional interpretations of Puerto Rico's first occupants have been somewhat basic, but the findings of this study and perhaps subsequent ones shed light on what was probably a more lively and diversified cultural landscape than was previously recognized.

The authors add: “This study assiduously documents the oldest dated burials from the island of Puerto Rico and provides detailed scientific and cultural insights into the lives of some of the earliest people to inhabit that island. We hope that this work contributes to the ongoing re-framing of our understanding of the deep past of Puerto Rico and the Caribbean.”

The study was recently published in PLOS ONE.

Study abstract:

We possess rather little detailed information on the lives of the first inhabitants of Puerto Rico—the so-called “Archaic” or “Pre-Arawak” people—despite more than a century of archeological research. This is particularly true bioarchaeological, as fewer than twenty burials of the several millennia of the Archaic Age have been recovered, let alone analyzed in any detail. Here, we present the results of archeological, osteological, radiometric, and isotopic analysis of five individuals from the Ortiz site in Cabo Rojo, southwestern Puerto Rico. The study of these previously unpublished remains, which represent a 20–25% increase in the sample size of remains attributed to the period, provides many critical insights into earliest Puerto Rican lifeways, including aspects of mortuary practice, paleodiet, and possibly even social organization. A review of their burial treatment finds a mostly standardized set of mortuary practices, a noteworthy finding given the site’s potential millennium-long use as a mortuary space and the possibly distinct place(s) of origin of the individuals interred there. Although the osteological analysis was limited by poor preservation, we were able to reconstruct aspects of the demography that indicate the presence of both male and female adults. Stable isotope analysis revealed dietary differences from later Ceramic Age individuals, while dental pathology indicated heavy masticatory wear attributable to diet and/or non-masticatory function. Perhaps most crucially, direct AMS dating of the remains confirms these as the oldest burials yet recovered from the island, providing us both with a glimpse into the lives of some of the island’s first inhabitants and with tantalizing clues to the existence of a different degree of cultural “complexity” than is often ascribed to these earliest peoples. The existence of what radiocarbon dates suggest may be a persistent formal cemetery space at the Ortiz site has potentially significant implications concerning the territoriality, mobility, and social organization of the earliest peoples of southwestern Puerto Rico.