A set of human footprints found in an ancient lake deposit in the south-west of the Nefud Desert is believed to represent the earliest securely dated evidence of modern humans in the Arabian Peninsula.
The footprints were discovered as part of the Palaeodeserts Project, which is examining climate change and human evolution in Saudi Arabia. It has so far identified 10,000 ancient lakes through satellite imagery. At the Alathar palaeolake, they found seven human footprints, as well as hundreds of animal tracks and fossils from the Middle Palaeolithic. These discoveries are discussed in a paper recently published in Science Advances (https://doi.org/10.1126/sciadv.aba8940).
OSL (optically stimulated luminescence) dating of the layers above and below the sediments containing the footprints determined that they were created in the last interglacial period, between roughly 112,000 and 121,000 years ago. They are believed to have been left by Homo sapiens, because modern humans are known to have been present in the Levant and Arabia at this time but Homo neanderthalensis were not. Analysis of the prints also indicated that the stature and mass of the individuals who created them were more in line with the morphology of late Pleistocene H. sapiens.
The seven footprints are believed to have been made by two, or possibly three, individuals. The footprints are oriented in different directions around the lake bed, suggesting that they were carrying out activities such as drinking and foraging, rather than simply walking across it.
The footprints and fossils of other large mammals, including elephants, equids, and bovids, were also found. The palaeoecological data show that the surrounding landscape would have been a semi-arid grassland at the time, making the lake an important gathering place for animals and humans alike.
As there is no archaeological evidence of butchery on animal bones found at the site and no stone tools were present, it is thought that it was not the location of a human camp, but rather a brief stop to take advantage of the resources around the lake. The footprints these individuals left behind offer a remarkable snapshot of that day around 120,000 years ago, as well as filling in an important gap in the story of early human presence in the area.