Fossils hint ancient humans passed through a green Arabia

The Arabian Peninsula is the part of southwestern Asia that includes Saudi Arabia and other countries. Today this region is known for its harsh deserts. But at least 300,000 years ago, it was a green hot spot for migrating members of the human genus. That’s the finding of a new study.

Patrick Roberts and his colleagues studied an ancient site called Ti’s al Ghadah. Roberts is an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany. This Saudi Arabian site held fossils of antelopes, elephants and other animals. Among those fossils were stone tools made by long-ago humans or their relatives. Those tools are between 300,000 and 500,000 years old.

Two animal fossils at Ti’s al Ghadah seemed to have butchery marks on the bones. In other words, someone cut up the carcasses to eat them. That would mean hunting happened at this site, the researchers now conclude.

The researchers looked at 21 animal teeth from the site. They were looking for chemicals that would indicate what the animals had eaten. Those chemicals suggest that the ancient environment looked like today’s grassy savannas in East Africa. Forms of carbon in the animals’ teeth reflected a grassy menu. And forms of oxygen showed that the animals regularly drank water from ponds or other sources fed by rainfall.

These data point to that long ago site as being a grassy, green region regularly fed by rain. The researchers described their findings online October 29 in Nature Ecology & Evolution.

Homo sapiens, our species, arose in Africa roughly 300,000 years ago. Later, members of our species left Africa and spread across the world. Scientists have estimated that those migrations began about 60,000 years ago. But recent finds on the Arabian Peninsula had suggested that those migrations began much earlier. For example, researchers found a human finger fossil from at least 86,000 years ago.

Some ancient toolmakers passed through Ti’s al Ghadah a few hundred thousand years ago. They may have been Homo sapiens. Or they may have been another Homo species that journeyed out of Africa, say Roberts and his team. Whoever they were, these groups found a friendly, green climate waiting for them.