Recent research reveals that ancient humans may have butchered a giant armadillo-like creature around 21,000 years ago in what is now Argentina. This discovery, detailed in a study published in the journal PLOS One, adds to a growing body of evidence suggesting humans spread across the Americas much earlier than previously believed.

An artist’s interpretation of ancient humans butchering a glyptodont in South America 21,000 years ago. Credit: Damián Voglino, Museo de Ciencias Naturales A. Scᴀsso (Colegio Don Bosco), San Nicolás de los Arroyos, Provincia de Buenos Aires, CC-BY 4.0)

The fossil remains, identified as belonging to a glyptodont species known as Neosclerocalyptus, were unearthed along the banks of the Reconquista River on the outskirts of Buenos Aires. This extinct armadillo relative, which weighed around 660 pounds and measured nearly six feet in length including its tail, had parts of its pelvis, tail, and carapace—bony plates covering its body—preserved. Radiocarbon dating of a pelvic bone fragment indicated the remains were between 21,090 and 20,811 years old, consistent with the geological dates of the sediment where the bones were found.

The research team, led by Dr. Mariano Del Papa from the National University of La Plata, conducted detailed analyses of the bones, uncovering 32 linear cut marks. These marks were not immediately visible but were revealed through careful cleaning and 3D scanning. The researchers determined that the V-shaped cross-sections of the marks were indicative of stone tool butchery, as opposed to U-shaped marks typically made by carnivores or other natural processes. This conclusion was supported by statistical techniques used to classify and compare the marks, confirming they were human-made.

“The cut marks were not randomly distributed but focused on those skeletal elements that harbored large muscle packs like the pelvis and the tail,” said Miguel Delgado, a paleoanthropologist at the National University of La Plata and co-author of the study, in an email to Live Science. He suggested that the size and muscle mᴀss of glyptodonts, which could provide a significant amount of meat, made them appealing targets for ancient humans.

Drawing of a Neosclerocalyptus skeleton highlighting cut-marked skeletal elements in light blue found at the CRS-10 specimen. Credit: Del Papa et al., PLoS ONE (2024)

The findings are significant as they push back the timeline of human presence and human-megafauna interactions in southern South America by nearly 6,000 years compared to previously recorded sites. This evidence aligns with other recent discoveries indicating early human presence in the Americas over 20,000 years ago.

Despite the lack of human-made tools found at the site, Delgado remains hopeful that additional excavations will uncover more evidence. “While we haven’t found any tools yet, it’s worth noting that we’ve only excavated a small portion of the site, and there may be more evidence, such as lithic tools,” he stated.

3D reconstructions of cut marks found in the Neosclerocalyptus sp CRS-10 specimen. Credit: Del Papa et al., PLoS ONE (2024)

The study’s results contribute to the ongoing debate about the timing and manner of early human migration to South America. Current estimates for the first inhabitants of the Americas range from 13,000 to over 20,000 years ago, but archaeological evidence has been sparse and often contentious.

More information: Del Papa M, De Los Reyes M, Poiré DG, Rascovan N, Jofré G, Delgado M (2024) Anthropic cut marks in extinct megafauna bones from the Pampean region (Argentina) at the last glacial maximum. PLoS ONE 19(7): e0304956. doi:10.1371/journal.pone.0304956