Scientists uncover oldest evidence of protein residue on stone tools

Researchers from the University of Victoria and colleagues in the US and Jordan just unearthed the oldest evidence of protein residue on stone tools, suggesting that early humans living 250,000 years ago in the Middle East were already using instruments to obtain food from animals.

Writing in the latest edition of the Journal of Archaeological Science, paleoanthropologist April Nowell and her colleagues explained they excavated a total of 10,000 stone tools from a site known as Shishan Mars, a desert oasis located close to Azraq, Jordan. Some of those tools included residual remains of horses, wild cattle, ducks, and rhinoceroses, they noted.

Image of one of the tools uncovered in the study (Credit: UVic)

Image of one of the tools uncovered in the study (Credit: UVic)

“Researchers have known for decades about carnivorous behaviors by tool-making hominids 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,” Nowell explained Monday in a statement.

“Based on lithic, faunal, paleoenvironmental and protein residue data, we conclude that Late Pleistocene hominins were able to subsist in extremely arid environments through a reliance on surprisingly human-like adaptations including a broadened subsistence base, modified toolkit, and strategies for predator avoidance and carcass protection,” she and her colleagues wrote.

Study shows that early hominid populations were surprisingly adaptable

Nowell and her colleagues recovered 10,000 stone tools from the excavation site, which is now a desert but was once an increasingly arid wetland, over a three-year period. They examined 7,000 of those instruments, including scrapers, flakes, projectile points, and hand axes, and found a total of 17 which tested positive for blood and other animal products.

Image of the site, which is quickly becoming a lush wetland

Image of the site, which is quickly becoming a lush wetland (Credit:

The discovery suggests that the people living in the region 250,000 years ago were able to adapt surprisingly well to a demanding habitat, the study authors said. “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,” explained Nowell.

“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,” she continued, adding that the team’s work “opens up our ability to ask questions about how Middle Pleistocene hominins lived in this region.”

In fact, the new study could result in an improved understanding of interbreeding and population dispersals involving modern humans, Neanderthals and other ancient populations across Europe and Asia, the authors said. Furthermore, the findings could shed new light on early hominin diets and provide a new way for researchers that have access to ancient tools obtained from other sites to determine if those early humans also ate animals, despite the lack of obvious remains.

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Image credit:  UVic