‘Inhospitable’ Arabian Peninsula was regularly visited by hominids in prehistoric times

Though long overlooked, this region, too, seems to be able to tell us much more about our own evolutionary history.

For a long time, the Arabian Peninsula was considered uninteresting for research into human evolution. While it’s beautifully situated – right between Africa and Eurasia – and it doesn’t seem too far-fetched that hominins traveled to Eurasia via the Arabian Peninsula, the climate there is far from welcoming. The area is desert-like and very different from the savanna landscape that hominids in Africa were used to. Still, researchers are starting to change their minds more and more. And a new study, published in the journal Nature, also explains why.

hippo bones

Today, Saudi Arabia is a hot and dry place. During the day temperatures can even reach well above 40 degrees Celsius. But that probably hasn’t always been the case. In a new study, researchers have found remnants of ancient lakes. For example, in the middle of the arid Nefud Desert, they found apparently misplaced mammal fossils. “The most remarkable were fragments of hippopotamus bones,” said researcher Julien Louys. “We currently only find these in wet environments in Africa. But when we also found them in the Nefud Desert, we were sure that the Arabian Peninsula has been significantly wetter in the past than it is today.”

green oasis

It is possible that the lakes formed after periods of intense rainfall, transforming the area into a green oasis. In the past few hundred thousand years, the Arabian Peninsula has probably experienced several such wet periods. It could have periodically transformed today’s uninhabitable Nefud Desert into lush grassland. And that’s very interesting. Because that could have turned the now arid and scorching hot region into a hospitable route for hominids.

Stone tools

Indeed, the researchers found that during each phase of ‘Green Arabia’, early hominids spread through the region. The researchers come to that conclusion after discovering several collections of stone tools. Thousands of artifacts reveal multiple ‘waves’ of human occupation. In addition, each wave is characterized by a different kind of material culture. The recovered stone tools made by early hominids are analyzed to be about 55,000, 100,000, 200,000, 300,000 and even 400,000 years old.

A 400,000 year old stone tool. Image: Palaeodeserts Project

It is a special discovery. Because it means that people were already present in Arabia some 400,000 years ago. The findings of the study are therefore described as a true ‘breakthrough in Arab archaeology’.

Intersection

The researchers state that northern Arabia was likely a crucial migration route and crossroads in prehistoric times. This is because in some cases the differences in the stone tools studied are so great that they indicate the presence of several hominids in the region. This suggests that populations arrived in the area from multiple directions and source areas. This diversity sheds new light on the magnitude of cultural differences in Southwest Asia during this period and points to highly divided populations. And that means Arabia may have been a frontier for several hominids from both Africa and Eurasia.

Overall, the findings show that the “inhospitable” Arabian Peninsula was likely frequented by hominins during wet periods in prehistoric times. And when the region dried up again, these populations moved on to more favorable climate areas. “Arabia has long been seen as an empty place in the past,” said study leader Huw Groucutt. But nothing turns out to be less true. Arabia appears to have a particularly rich prehistory.

Future research in Arabia promises to fill many gaps in our knowledge of our own human evolutionary history. “Our work shows that we actually know very little about human evolution in large parts of the world,” continues Groucutt. “It highlights the fact that we are still often faced with surprises.”