Over the last few years there has been a small but growing body of evidence to show that humans arrived in the Americas some 7,000 years before the accepted date of c.13,000 BC for the emergence of the Clovis culture. Most of the evidence for an earlier date is contestable: stones that might be tools or might have been shaped by natural processes, or fires with food remains that could be interpreted as hearths but that might also be the remains of a lightning strike or bush fire.
The latest evidence is vividly human, however. A team from the US Geological Survey has found numerous footprints formed in soft mud on the margins of a shallow lake at Alkali Flat in White Sands, New Mexico. Writing in the journal Science, the team reports that the layer in which the footprints were found was sandwiched between seed-bearing sediments. Radiocarbon dates for the seeds place the footprints at 23,000 to 21,000 years old.
It is highly likely that there were many migrations into the Americas in prehistory, but none of these older settlement episodes seems to have been long-lasting, as they have left no record in the genome of today’s indigenous Americans. It is likely that the numbers involved were too small to form sustainable communities.
Excavating the CA archive