Archaeologists have found 115,000-year-old human footprints where they shouldn’t be. Fossilized footprints in Saudi Arabia show evidence of human movement on the cusp of the next ice age. Study of preserved tracks in New Mexico continues to shed light on the first human movements across North America.
Archaeologists have found 115,000-year-old human footprints where they shouldn’t be. Fossilized footprints in Saudi Arabia show evidence of human movement on the cusp of the next ice age. Like radiocarbon dating, scientists use isotopes and context clues to calculate the approximate age of fossils.
These human footprints were surrounded by animals, but not prey, suggesting the people were simply thirsty. A uniquely preserved prehistoric mud pit may contain the oldest human footprints in the Arabian Peninsula, scientists say. The seven footprints, found among hundreds of prehistoric animal prints, are estimated to be 115,000 years old.
Many fossils and artifacts have been found in bodies of water, like this particular lake bed in northern Saudi Arabia. Archaeologists discovered the site deep in the Nafud Desert in what is known in Arabic as “the footprint” in 2017, after time and weather had worn away the sediment above. It’s easy to imagine that the muddy lake bed was the site of intense movement in the Arabian Peninsula more than 100,000 years ago.
When populations move, these imprints remain until they are buried. In the much older Burgess Shale event, some of the oldest organisms ever found were preserved intact because they were likely caught in a landslide and killed instantly. An entire armoured nodosaur was found in unprecedentedly good condition because it was encased in mud and the cold of the sea floor. If there was a price for finding incredible archaeology, much of it would be paid in mud.
In their new paper, the scientists actually explore why this ancient mud was so special in the first place:
“An experimental study of modern human tracks on mudflats showed that fine details disappeared within two days and the prints became unrecognizable within four days, and similar observations have been made for the tracks of other non-hominin mammals.”
This means that a specific, tiny batch of preserved footprints were made under unique conditions, which also forms a kind of “fingerprint” to attach them all to a single time frame. From there, scientists began to look at who made the footprints. Homo sapiens was not the only upright humanoid primate at this time:
“Seven hominin tracks were confidently identified, and given the fossil and archaeological evidence for the spread of H. sapiens into the Levant and Arabia between 130,000 and 80,000 years ago and the absence of Homo neanderthalensis in the Levant at that time, we argue that H. sapiens was responsible for the tracks at Alatar. Furthermore, the size of the tracks at Alatar is more consistent with those of early H. sapiens than H. neanderthalensis.”
The lake that forms Alatar today was probably part of a prehistoric highway that attracted all the large animals in the area, creating a corridor dotted with freshwater resting areas through which living creatures could move, migrating according to the weather or changing climate. In this case, scientists have found very few other factors that accompany prehistoric human travel, such as knife marks or tool marks on animal bones indicating hunting.
“The lack of archaeological evidence suggests that Lake Alatar was visited by humans only for short periods of time,” the scientists conclude. “These results indicate that temporary human use of the lake shores during the dry period of the last interglacial was likely primarily related to the need for drinking water.”
These Homo sapiens may have been the last ones on their way before the Ice Age approached. This would also explain why their tracks were not passed by another group, at least not until a whole fresh layer of sediment had accumulated.
A study of preserved tracks in New Mexico continues to shed light on the first human movements across North America. The research team believes the prints are more than 23,000 years old, confirming earlier research that dated the prints to be 10,000 years older than previously thought.
White Sands National Park is home to some of the most archaeologically rich sands in North America, and it is in this New Mexico landscape that the oldest footprints ever found on the continent were discovered. Recent research dates these footprints to about 23,000 years ago—about 10,000 years before humans were previously thought to have existed in North America.
“This site in New Mexico has rewritten the history books because we have discovered remarkable examples of human activity, the ways in which people interacted with each other, with the landscape and with wildlife,” Sally Reynolds, principal research fellow in palaeoecology at Bournemouth University, said in a statement. “These tracks provide valuable insight into how our ancestors lived and how similar they were to us.”
Previously thought to be around 13,000 years old, a 2021 study by U.S. Geological Survey researchers instead dated the tracks to around 23,000 years ago using radiocarbon dating techniques. The team wanted to confirm these findings, however, and published another study in Science in late 2023 that confirmed the newly “calibrated” aging of the tracks using fossilized pine pollen dating.
With pollen and ditch grass seeds found in both the footprints and the same layer of hardened mud in which the footprints were found, the team was able to confirm a new date of 23,000 years, showing that humans were on the continent during the Last Glacial Maximum. The team also used optical stimulated luminescence to study the background radiation in quartz. The more energy in the quartz, the older the find. This helped confirm the date.
Matthew Bennett, a professor at Bournemouth University and co-author of the study, said in a statement that the team was pleased that after further examining the original study they were able to provide new results that “underline the accuracy of our original research and provide exciting new insights into the movements and lifestyles of our ancestors.”
And there were plenty of such movements. As noted in the Smithsonian paper with Bennett, tracks in the White Sands area show children playing near puddles, hunters tracking a giant sloth, and a young woman carrying a child who slips in the mud, perhaps while being pursued by a predator.
“There were hungry predators around, including dire wolves and saber-toothed cats,” Bennett said. “We can see where she slipped in the mud in certain places. … We can also see the footprints of the baby where she put it down, presumably because she was tired and needed to rest.”
Some traces can be detected without the use of technology, while others require ground penetrating radar to detect.
“The evidence left at White Sands gives us a sense of what was going on: adolescents interacting with younger children and adults,” Bennett said in a statement. “We may think of our ancestors as being quite functional, hunting and surviving, but what we see here is also playful activity and a mix of ages. A real insight into these ancient people.”
Bennett said that while the tracks found in the area provide only a small glimpse into what life was like 23,000 years ago, the team hopes to find more tracks to tell a more complete story of life in North America.