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The oldest known human footprints in the Americas were found in an ancient lake bed in what is now White Sands National Park in New Mexico. Dating back to between 23,000 and 21,000 years, the footprints challenge many widely established theories about how and when humans first arrived on the continent.
The trails were first spotted by David Bustos of White Sands National Park, who had encountered many of these trails on a trip through the White Sands area. Astonished by his discovery, he invited a team of scientists to inspect the footprints in January 2016, marking the start of the ongoing excavation program. Today, a multinational team of The University of Bournemouth in the United Kingdom, the University of Arizona, the US Geological Survey and the National Park Service published the analysis of this groundbreaking discovery in the journal Science.
Eventually, the team confirmed that the set of footprints was created by humans, including children and adolescents, as well as mammoths and a dog-like carnivore. Even more surprisingly, an analysis of the surrounding sediment layer revealed that human traces were imprinted on the ground between 23,000 and 21,000 years ago.
“These are the oldest known and well-dated fingerprints in the Americas,” Dr Sally Reynolds, co-author and mammalian paleontologist at the University of Bournemouth, told IFLScience.
The story of how and when people first arrived in the Americas is still the subject of heated debate. Until recently, the most widely accepted view was that the first inhabitants of the Americas were a group known as the “Clovis culture” that settled on the continent about 15,000 to 13,000 years ago.
More recent discoveries have pushed back this timescale, with estimates for the arrival of these first occupants. ranging from 25,000 years to 33,000 years. However, concrete evidence is lacking. These recently discovered footprints indicate with certainty that humans trampled the Americas at least 21,000 years ago.
Tools and bones can migrate to different layers of sediment, which are used to date them. “Footprints are very fragile in a sediment and cannot migrate downward, like a tool or a bone might under certain conditions,” explained Dr Reynolds. “The number of footprints and their clear shape means they are unmistakably humans.”
This could have huge implications for our understanding of prehistoric human migration. Most researchers believe that the first humans from the Americas arrived from Asia via the Bering Land Bridge, which formed between northeast Siberia and western Alaska. They then traveled south through an ice-free interior corridor in western Canada and / or via a Pacific coastal route.
However, about 23,000 years ago, this part of the world was entered during the last ice age, aka the last ice maximum (LGM). It was previously assumed that this migration across America would have been too difficult to cross during the LGM. These bold prints clearly say otherwise. However, it is not clear exactly how the humans managed to make this treacherous journey.
“In light of the results, this means that the first migrations would have taken place via Asia, on the Bering land bridge and in Alaska. We previously thought they would move south after around 16,000 [years ago] when the ice caps melted and a migration corridor opened, but the earlier date from White Sands shows humans were already in the Americas, ”Reynolds said. “This means that humans migrated to the Americas much earlier, but still by the same route. “
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