New evidence has been found that proves humans lived in North America 7,000 years earlier than archaeologists thought.
Fossil footprints discovered on the shores of an ancient lakebed in New Mexico's White Sands National Park are 23,000 years old, making them one of the oldest finds in North America.
This timing suggests that humans occupied the southern part of the continent at the peak of last ice age. This changes our understanding of how and when they moved south.
It was believed that the land bridge that connected Siberia and Alaska in the last ice age (26,500 to 19,000 years ago) was the original way that North Americans were first occupied.
They would have to settle close to the Arctic, because Canada's ice sheets made it impossible to travel south.
Later, when these glaciers had melted between 16,000-13,500 years ago and the melting of further glaciers, South America's migration began.
One of the footprints. (Reynolds et al., Science, 2021)
However, this new finding "definitively places people in North America at a time when the ice sheets curtains were very firmly closed," Sally Reynolds (paleoecologist at Bournemouth University, England) told Insider.
Reynolds stated that it is most likely that humans moved south in multiple waves. One wave was prior to the last ice age. It is possible that those early people could have sailed down to the Pacific coast.
Reynolds stated, "Then more fell after the ice receded."
This discovery was published in Science on Thursday. The study also includes tracks from mammoths and dire wolves nearby.
The oldest footprints found in America
Reynolds' team discovered 60 human footprints that were between 21,000 to 23,000 years old. Researchers used microscopic seeds of an aquatic plant to date the tracks.
Reynolds stated, "It's unambiguous evidence." "The layers go seeds footprints seeds seeds."
These footprints now rank as the oldest footprints in America, surpassing a Chilean footprint that was 15600 years old a decade ago.
The majority of tracks belonged to children and teens, according to the team. This could indicate that the kids played in the area as adults hunted and collected.
Reynolds stated that the earliest date for when humans first occupied North America was 16,000 Years ago, prior to this discovery.
A set of tools and artifacts made from stone found in a remote Mexican cave is the only way to tell if people arrived earlier. Reynolds stated that although archaeologists believe that the sediment that ensconcing these artifacts is 32,000 years old it's not an accurate measure. Over time, artifacts can move up and down between sediment layers.
Reynolds stated, "Footprints are, in contrast, fixed on the landscape."
White Sands National Park has some of the most interesting fossil footprints. (Reynolds et al., Science, 2021)
The possibility that humans could have traveled south by boat is possible
Reynolds stated that it is not yet known how humans got to White Sands, but there are many theories.
One theory suggests that they traveled westward along an ice-free corridor. Another suggests they traveled by boat, perhaps sailing from Japan or Russia and then expanding south along the Pacific Coast.
Reynolds stated that she believes it is possible that our ancestors may have crossed the continent and then sailed along the Atlantic coast before traveling to New Mexico.
She said, "There's this hovering doubt mark over the role their seafaring abilities."
In North America, giant sloths were hunted by ancient humans
This isn’t the first amazing discovery made at White Sands.
Reynolds stated, "Its worth goes far, far beyond these new footprints."
Her team discovered a new set of animal and human tracks on the site three years ago. They date back to approximately 15,500 years ago. These footprints revealed an epic battle of predator and prey: A man was following a large sloth.
Reynolds stated that "the human was walking right behind" Reynolds, and added, "And the sloth absolutely does not like it."
The 12,000-year-old extincture of giant ground sloths was a shock. Around the same time, 90 percent of large-bodied animals, including mastodons and prehistoric horses, went extinct.
Many archaeologists believe that the mass extinction in America occurred within a few millennia after their arrival.
Reynolds stated, "Humans appear and megafauna begin dying." It seems like there is a clear cause-and-effect relationship.
Business Insider originally published this article.
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