Life-size rock art points the way to oldest human inhabitants of Saudi Arabia — and the desert oases they used

Archaeologists in Saudi Arabia have discovered 12,000-year-old life-sized animal etchings — "monumental rock art" that dates to over 2,000 years before humans were thought to be in the region, a new study finds.

These highly realistic depictions of camels and other creatures were likely culturally meaningful for these hunter-gatherers, and probably served as waymarkers to help people locate oases that popped up when the area became wetter starting from 16,000 to 13,000 years ago, the researchers wrote in the study, which was published Tuesday (Sept. 30) in the journal Nature Communications.

The rock art could have also marked ancient travel routes or even signified the territory of a group and its intergenerational memory, the researchers said. These findings ultimately show that "humans were able to survive in the desert very early on, much earlier than we thought and in much harsher conditions than we thought,"study co-author Maria Guagnin, an archaeologist at the Max Planck Institute of Geoanthropology in Germany, told Live Science.

At the crossroad between Africa and Asia, Arabia was a key migration route for early humans, with research published April 9 in the journal Nature confirming the region underwent various "humid episodes" that enabled these dispersals. Yet there previously was no evidence of human occupation in northern Arabia between the end of the Last Glacial Maximum (around 25,000 to 20,000 years ago), the coldest period during the last ice age, and around 10,000 years ago. Researchers assumed the area had been abandoned because it was too arid to survive.

Now, following a tip from local amateur archaeologists about a giant piece of rock art, researchers have explored three previously unknown sites in the southern Nafud Desert in northern Saudi Arabia that upend that assumption.

When they arrived, one teammate wandered off to explore the area and discovered "the first big excitement," a rock formation with ancient art surrounding a pool of water, Guagnin said. And on the other side of the mountain were the remains of an ancient lake.

The team subsequently found 62 rock art panels with 176 engravings across the three sites, with some etched into huge cliff faces 128 feet (39 meters) up. The engravings were predominantly of life-sized animals, mainly camels.

Importantly, these depictions were commonly of male camels with distinctive bulges around their necks that they form during the mating season and thick winter fur. This suggests that the ancient water sources may have formed in winter, and may have also symbolized the resilience of these animals to the harsh environment, the authors speculated in their study.

Digging up the desert

The archaeologists excavated directly below four camel engravings to try to determine their age. They unearthed over 1,200 stones, 16 animal bone fragments and three hearths. The team dated these using luminescence dating, a technique that measures when sediments were last exposed to heat and sunlight, and radiocarbon dating, which measures the ratio of different versions of carbon.

These methods revealed that the rock art was between 12,800 and 11,400 years old.

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One of the camel rock art panels found in the Nafud Desert of northern Saudi Arabia.

The ancient stone pecking tool used to create the camel etchings.

An arrowhead uncovered during the excavations.

At one excavation site, the camels' legs had been obscured by layers of sediment. When they dug down, the team were amazed to find the stone tool likely responsible for creating the masterpiece, which they dated to around 12,200 years ago. This provides "an indirect date for the engraving," the authors wrote in the study.

They also found arrow points, bladelets and stone beads; but "this isn't just a handful of arrowheads," Guagnin said. A community lived in the region and crafted tools and ornaments typical of the Natufian culture in the Levant, many miles away around the eastern Mediterranean. "They were in contact with the Levant somehow across hundreds of kilometers," she said, and learned about the latest tools and accessories.

Crucially, "some things are imported but then some things are unique," study co-author Michael Petraglia, an archaeologist at Griffith University in Australia, told Live Science. These people were also developing their own culture, with the rock art having symbolic meaning as well as being clear ways of marking routes to water sources, he said.

An analysis of the sediments in the dried up water sources revealed the region had become more humid starting around 16,000 to 13,000 years ago, forming seasonal lakes. This discovery represents the earliest evidence of increased humidity in northern Arabia after the Last Glacial Maximum.

"This is a very exciting study revealing a part of Saudi Arabian history that has so far not been readily visible," Hugh Thomas, an archaeologist specializing in Saudi Arabia at the University of Sydney who was not involved in the study, told Live Science in an email. He said that these results show that "the entire region was populated and that even at this time, it was an interconnected landscape."

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