Five Stone Age tools used by early humans 250,000 years ago yielded evidence of horse protein, indicating that the animals were butchered, researchers report.
New research published in the Journal of Archaeological Science reveals surprisingly sophisticated adaptations by early humans living 250,000 years ago in a former oasis near Azraq, Jordan.
The research team has found what they say is the oldest evidence of protein residue — the residual remains of butchered animals including horse, rhinoceros, wild cattle and duck — on stone tools.
The discovery draws startling conclusions about how these early humans subsisted in a very demanding habitat, thousands of years before Homo sapiens first evolved in Africa.
The team excavated 10,000 stone tools over three years from what is now a desert in the northwest of Jordan, but was once a wetland that became increasingly arid around 250,000 years ago.
The team closely examined 7000 of these tools, including scrapers, flakes, projectile points and hand axes (commonly known as the “Swiss army knife” of the Paleolithic period).
Forty-four were subsequently selected as candidates for testing. Of this sample, 17 tools tested positive for protein residue — that is, blood and other animal products. Five of them were positive for evidence of horse protein, three for rhinoceros, three for duck, three for bovine and three for camel.
“Researchers have known for decades about carnivorous behaviours by tool-making hominins dating back 2.5 million years, but now, for the first time, we have direct evidence of exploitation by our Stone Age ancestors of specific animals for subsistence,” said paleoanthropologist April Nowell, of Canada’s University of Victoria.
Nowell, who led the study team, continued: “The hominins in this region were clearly adaptable and capable of taking advantage of a wide range of available prey, from rhinoceros to ducks, in an extremely challenging environment.
“What this tells us about their lives and complex strategies for survival, such as the highly variable techniques for prey exploitation, as well as predator avoidance and protection of carcasses for food, significantly diverges from what we might expect from this extinct species.
“It opens up our ability to ask questions about how Middle Pleistocene hominins lived in this region and it might be a key to understanding the nature of interbreeding and population dispersals across Eurasia with modern humans and archaic populations such as Neanderthals.”
Another result of this study is the potential to revolutionize what researchers know about early hominin diets.
“Other researchers with tools as old or older than these tools from sites in a variety of different environmental settings may also have success when applying the same technique to their tools, especially in the absence of animal remains at those sites,” she added.
This research was fully funded by a grant from the Social Sciences and Humanities Research Council of Canada.
The paper is co-authored by Nowell and Daniel Stueber, both from the University of Victoria; Christopher Ames, also of the University of Victoria and the University of California, Berkeley; Cameron Walker, of Oregon Health and Science University; Carlos Cordova, of Oklahoma State University; James Pokines, of Boston University School of Medicine and with the Office of the Chief Medical Examiner in Boston; Regina DeWitt, of East Carolina University; and Amer Al-Souliman of Hashemite University in Jordan.
Middle Pleistocene Subsistence in the Azraq Oasis, Jordan: Protein residues and other proxies
A. Nowella, C. Walker, C.E. Cordova, C.J.H. Ames, d, J.T. Pokines, D. Stueber, R. DeWitt, A.S.A. al-Souliman.
The abstract can be read here.