Fossilized footprints as old as about 23,000 years found in New Mexico have been verified, indicating that the early humans were passing through North America during the last ice age.
In 2009, the footprints were found in a dry lake bed in White Sands National Park. The US Geological Survey recently analysed the seeds stuck in the footprints and concluded that the approximate age of the tracks ranged between around 22,800 and 21,130 years.
The authors of the research, which was published in the journal titled ‘Science’ on Thursday, said that the analysis provides a better timeline as to when humans were in North America; although they could have arrived even earlier.
The authors said that fossil footprints are more indisputable and direct evidence than “cultural artefacts, modified bones, or other more conventional fossils”.
“What we present here is evidence of a firm time and location,” the authors added
Researchers said that at least some of the prints were made by children and teenagers, a claim they base on the size of the footprints.
White Sands National Park’s Resource Program Manager David Bustos spotted the first footprints in 2009 and since then, he and others have found more in the park.
Bustos said, “We knew they were old, but we had no way to date the prints before we discovered some with (seeds) on top. The only way we can save them is to record them — to take a lot of photos and make 3D models.”
Bustos said that the researchers had to work quickly to gather samples as the footprints – made of fine silt and clay – are fragile.
Earlier excavations in White Sands National Park have uncovered fossilized tracks left by a sabre-toothed cat, dire wolf, Columbian mammoth, and other ice age animals.
Before this discovery, most scientists believed that humans made the ancient migration by the now-submerged land bridge that connected Asia to Alaska. These claims were based on various evidence including stone tools, fossil bones and genetic analysis. Meanwhile, other researchers had provided a range of possible dates for human arrival in the Americas, from 13,000 to 26,000 years ago or more.