Hundreds of ancient human footprints preserved in time between 5,000 and 19,000 years ago could vanish if left exposed to the elements, according to new research published in Quaternary Science Reviews.
First described in 2010, researchers cataloged more than 400 footprints at a mudflat near the base of Tanzania’s volcano Ol Doinyo Lengai, or “Mountain of God” in Massai, six years later. The site is known as Engare Sero and is home to the most abundant Homo sapiens footprints from the late Pleistocene period in Africa. Some of these footprints have already vanished in the decade since their discovery, and others are at risk from erosion, reports National Geographic.
“With each year that elapses, the quality of the footprint site decreases,” wrote the authors. “This has an impact on the viability and longevity of the site as a potential tourist attraction as well as a detrimental effect on the suitability of the site to produce robust data for future scientific inquiries.”
The footprints tell a tale of our ancient ancestors, showing men, women, and young children jogging, walking, and limping across the mudflat, revealing how – and where – our ancestors walked millennia ago. Previous research suggests the prints were first tracked in mud rich in ash from the nearby volcano that dried out between a few hours and days later. Afterward, another flow covered the footprints 10,000 to 12,000 years later, keeping them safe from the elements until less than a decade ago
The study reports a footprint can be worn down by a tenth to a sixth of a millimeter each year, but others have lost as much as a quarter of an inch in the last seven years.
Located in a river channel, the footprints get washed away during the rainy season. During the dry season, winds blow sands across the arid bed, further breaking down the muddy prints. Animals and humans also play a role in compacting the soil encompassing the prints, including tourists, who the authors note will “measure one's own footprint by placing it within one of the preserved prints, potentially damaging it.”
A digital backup of the site was scanned in 2010 and now rests at the Smithsonian Institution Digitization Program Office.
Today, a rock wall built around the prints is meant to divert rainfall and a fence around the perimeter serves to prevent people from walking over the footprints. Even so, researchers urge more action is needed to protect the site, which they say provides insights into early human physiology, anatomy, and social structures. They hope to digitally preserve in greater detail as many of the prints as possible, as well as monitor short- and long-term erosion changes that can help inform changes about future tourism and research purposes.
[H/T: National Geographic]