'Out of Africa' human migration timeline pushed back even further by new discovery

When did humanity’s early hominin ancestors first leave Africa and migrate into Europe and Asia? Good question. It seems like each time scientists think they have a definitive date, a new discovery is made that pushes the timeline back even further.

Until very recently, experts believed that these early ancestors first reached Eurasia about 1.8 million years ago.

However, new findings by an international research team suggest a different timeline that nudges the date back to nearly 2 million years ago.

Unearthing clues from Grăunceanu

To investigate this question, researchers headed to Grăunceanu in Romania. Nestled in the picturesque Olteț River Valley, this area hosts numerous fossil sites first uncovered in the 1960s.

The sites offer tantalizing glimpses into the ancient past, but researchers faced a significant challenge: the conspicuous absence of hominin bones.

Without any fossilized bones to analyze, the researchers sought alternative sources of evidence that might indicate the presence of ancient hominins.

At Grăunceanu, researchers embarked on an examination of over 5,000 bones, which were scrutinized for the signs of possible cut marks. These would have indicated the use of stone tools to remove animal flesh from the bones.

From this sea of fossils, the team zeroed in on 20 bones that confidently displayed the tell-tale marks of tool use.

Dating ancient bones with tool marks

“We didn’t initially expect to find much,” shared research lead, Sabrina Curran, associate professor of anthropology at Ohio University.

However, a routine check of the collections led to the discovery of several cut-marked bones, sparking a deeper investigation that uncovered “distinct marks across different bones, suggesting deliberate butchering activities.”

By employing biostratigraphic data and precise uranium-lead dating techniques, it was determined that the minimum age of these bones was around 1.95 million years.

This is significantly earlier than anticipated and represents a shift in our understanding of early hominin history.

Interpreting a prehistoric palette

Factoring into the narrative is Dmanisi, an archaeological site in Georgia which, until this discovery, was regarded as home to the oldest evidence of hominin activity outside Africa – dated to approximately 1.8 million years ago.

Verification of the age of the cut-marked bones in Grăunceanu, Romania, however, pushes the timeline of the presence of hominins in Eurasia back by almost 200,000 years.

Not only does this suggest early hominin presence in Eurasia, but it also elucidates aspects of their tool use from that era.

Environment of early hominin habitation

Further inquiry into the environment that our early ancestors inhabited was undertaken through isotopic analyses by Virgil Drăguşin from the “Emil Racoviţă” Institute of Speleology.

It seems this region would have witnessed seasonal temperature variations akin to those of the present day, but levels of rainfall would have been higher.

Additionally, the hominins entering these new territories would have encountered a variety of unique fauna, including wooly rhinos, saber tooth cats, pangolins, and mammoths.

They would have needed to be highly adaptable in these relatively unfamiliar environments.

Debate on early hominin migration

“People get really fired up about human ancestors, and one ongoing debate has been related to the earliest evidence of tool use,” noted Associate Professor Claire Terhune from the University of Arkansas.

“Because of this, we have been extremely meticulous in documenting the presence of these cut marks because we knew if we handed another paleontologist these bones, they’d say, ‘Oh, yeah these are cut marks.’ But if we told them they’re from Romania two million years ago, they’re going to say, ‘No, that can’t be right,’” she explained.

Indeed, the discovery at Grăunceanu is pivotal in understanding our human prehistory.

It challenges long-held assumptions about the timing and pace of early hominin dispersal, suggesting a more dynamic migration process than previously believed.

These findings also raise new questions about how early humans adapted to novel ecosystems, particularly in colder, temperate regions of Eurasia.

“It demonstrates that early hominins had already begun to explore and inhabit diverse environments across Eurasia, showing an adaptability that would later play a crucial role in their survival and spread,” Dr. Curran said.

“We are just beginning to uncover the many chapters of that story,” she added.

The full study was published in the journal Nature Communications.

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