120,000-year-old human footprints found in Saudi Arabia

Undated photo of animal fossils found on the surface of an ancient lake in Saudi Arabia.

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120,000 years ago in modern northern Saudi Arabia, a group of Homo sapiens, humans identical to ourselves, stopped near a lake also frequented by camels, buffaloes and elephants larger than current species.

The visitors did not stay long, the lake being only a stopover on a long journey.

The scene was reconstructed by researchers in a study published this Thursday in the journal

, after the discovery of ancient traces of human and animal footsteps in the Nefoud desert, new clues on the paths taken by our distant ancestors. after leaving Africa.

In our latest research, published in Science Advances and lead by @ StewieStewart13, we describe ~ 120,000 year old fossilized footprints embedded in an ancient lake deposit in Saudi Arabia.

THREAD (1 / n) pic.twitter.com/p5N35gtoVT

- Richard Clark-Wilson (@ rclarkwilson199) September 17, 2020

The Arabian Peninsula today is made up of large unwelcoming deserts, but scientists have for a decade established that it was once greener and wetter.

"There were times in the past when the deserts that dominate the interior of the peninsula turned into large grasslands, with the presence of permanent lakes and rivers", explains one of the authors of the study. , Richard Clark-Wilson, Royal Holloway University of England.

Seven footprints have been confirmed as belonging to hominids

The first author of the study, Mathew Stewart, of the Max Planck Institute in Germany, says he discovered the footprints during his doctorate in 2017, after the erosion of sediment at the site of an ancient lake called "Alathar" ( “The trace”, in Arabic): “Footprints are a unique form of fossil evidence that represents an instant in time, on the order of a few hours or days.

We do not have this resolution with the other readings.

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Of the set of footprints discovered [dated using a technique called stimulated optical luminescence], seven were confirmed to belong to hominids, four of which belonged to two or three individuals traveling together, given their common orientation. , the distance between them and the size differences.

Scientists also unearthed 233 fossils on site.

For researchers, the stature and mass of humans consider it to be modern humans and not Neanderthals, the latter not having been present in this region at the time.

The fact that the stone tool was not discovered leads researchers to rule out that the site was permanently inhabited.

"It seems that these people were passing by the lake to get water and to find food, at the same time as the animals", details Mathew Stewart.

Scientists also unearthed 233 fossils on site, supporting the hypothesis that carnivorous species came to hunt herbivores around the lake, as they do today in African savannas.

It has been established that humans colonized Eurasia from Greece and the Levant, exploiting coastal resources.

This new work examines that "inland routes, following lakes and rivers, may have been particularly important," according to Mathew Stewart.

"The presence of large animals such as elephants and hippos, combined with the vast grasslands and abundant aquatic resources, may have made northern Arabia very attractive to humans between Africa and Eurasia", summarizes another author, Michael Petraglia, of Max Planck.

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