Why Are Scientists Excited About these Ancient Footprints?
by Jazmin Becerril Gonzalez, age 14
A study published last year in the journal Science suggests that humans reached North America long before prior scientifically-accepted evidence was established, approximately 23,000 thousand years ago. The researchers behind this study came to this conclusion due to recently-discovered human footprints dating back to this time period.
Matthew Bennett, a researcher at Bournemouth University in England, led a group of scientists to investigate these newly-uncovered fossilized footprints. These fossils were found next to a lakebed located in White Sands National Park in New Mexico, an area filled with chalk-colored sand dunes. The team of researchers concluded that these footprints had resulted from mostly children and teenagers walking around this location during a several-thousand-year period.
The researchers were able to date these fossils more accurately due to the fact that footprints remain trapped in place with sediment layers. "One of the beautiful things about footprints is that, unlike stone tools or bones, they can't be moved up or down the stratigraphy," Bennett says. "They're fixed, and they're very precise." As Bennett and his colleagues researched the footprints, they also discovered fossilized seeds from a species of ancient aquatic plant called spiral ditch grass in the sediment layers. These seeds could easily be carbon-dated which gave the research team a relatively-precise estimate for the age of the footprints. The age they settled on for these footprints ranged between 21,000 to 23,000 years ago, a time period landing during the last Glacial Maximum.
Two studies published within the last 10 years had attempted to prove that humans reached North America earlier than thought. The first, a 2017 study was published claiming that humans actually reached North America around 130,000 years ago. However, this study was discredited because of flaws in its conclusions. The claims were largely based on assumptions about evidence that later turned out to be unsupportable. Markings on animal bones were not made by humans, as assumed, but instead were explainable by natural causes, and objects thought to be tools were in fact just rocks. The second study, published in 2020, similarly mistook rocks found in Chiquihuite Cave in Mexico for tools made by humans allegedly 26,000 years ago.
The question of how long ago humans actually reached North America has been a topic of debate among scientists for many years. Despite previous studies failing to prove the earlier appearance of humans on this continent, Bennett’s research brings new compelling evidence of such ancient human migration.
[Sources: National Public Radio; National Park Service; Bournemouth University]