Fossilized footprints dating back 23,000 years push back the known history when the continent was colonized thousands of years ago.
Footprints dating back 23,000 years have been discovered in the United States, indicating that humans settled in North America long before the end of the last Ice Age, according to researchers.
The results announced Thursday delay the date when the continent was colonized by its first inhabitants by thousands of years.
Footprints were left in the mud on the banks of a long-dry lake, which is now part of the New Mexico desert.
The sediments filled in the gaps and solidified in the rocks, protecting evidence of our ancient relatives, and giving scientists a detailed look into their lives.
The first footprints were found on the bottom of a dry lake in White Sands National Park in 2009. Scientists at the US Geological Survey recently analyzed seeds stuck in the footprints to determine their approximate age, which ranges from 22,800 to 21,130 years ago.
“Many of the tracks appear to be for adolescents and children; “large adult footprints are less frequent,” wrote the authors of the study published in the American journal Science.
One hypothesis for this is the division of labour, in which adults engage in skill-requiring tasks while ‘fetching and carrying’ is delegated to adolescents.
“Children accompany teens, and collectively they leave more footprints.”
The researchers also found footprints left by mammoths, prehistoric wolves, and even giant sloths, which appear to have been around the same time humans visited the lake.
The Americas was the last continent that mankind reached.
For decades, the most popular theory was that settlers came to North America from eastern Siberia via a land bridge – the present-day Bering Strait.
From Alaska, head south for a much nicer vibe.
Archaeological evidence, including spearheads used to kill mammoths, has long suggested a 13,500-year-old settlement linked to the so-called Clovis culture – named after a town in New Mexico.
This was considered the first civilization on the continent, and the forerunner of the groups that came to be known as Native Americans.
However, the idea of Clovis culture has been challenged over the past 20 years, with new discoveries putting the era of the first settlements back.
In general, even this deferred estimate of the age of the first settlements was no more than 16,000 years, after the end of the so-called “last glacial maximum” – the period when the ice sheets were most widely spread.
This episode, which lasted until about 20,000 years ago, is crucial because it is believed that with ice covering most of the northern parts of the continent, human migration from Asia to North America and beyond would have been very difficult.