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Oldest footprints in North America push back human arrival

83 points| isaacfrond | 2 years ago |washingtonpost.com

74 comments

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[+] BMorearty|2 years ago|reply
I'm confused by this article. It says "New evidence adds to work showing people made these prints [in New Mexico] sometime between 21,000 and 23,000 years ago." It supposedly contradicts experts' belief for decades that "the first people in the Americas migrated from Siberia across the Bering Strait on a land bridge exposed during the last glacial maximum, sometime between 26,500 and 19,000 years ago.

How is that contradictory?

[+] jcranmer|2 years ago|reply
The traditional thesis of the peopling of the Americas is that people arrive in Beringia (not entirely accurate to say they crossed the Bering Strait--there was no Bering Strait, and Beringia was where the Bering Strait is now!), c. 20-odd thousand years ago. About 13,000 years ago, a gap opens between the Rocky Mountains and the Laurentide Ice Sheet, and settlers traveled through this "ice-free corridor" to reach what is now the US, where they flourish as the Clovis culture. This is known as the Clovis-First hypothesis--that Clovis was the first material culture to leave Beringia and people the rest of the Americas.

However, there's a lot of evidence that people had spread out to the rest of the Americas well before Clovis, and it's now known that the "ice-free corridor" opens up too late--it opens up even after we see traces of Clovis-First. By around the 1990s, the anthropological community has accepted that Clovis-First is complete and utter rubbish, although there is still disagreement about the timetable. I'd wager seriously arguing Clovis-First among scientists would get you as much derision as seriously arguing geocentrism among astronomers.

Annoyingly, popular anthropology lags science tremendously. It probably took a decade or two for textbook writers to bother to update their textbooks to consider the rejection of Clovis-First (hell, when I was in school, the textbook didn't even bother to present alternative hypotheses than Clovis-First, although our teachers were knowledgeable enough to tell us in class that, well, textbook's got it wrong there), and then perhaps another decade for schools to get around to new textbooks. It's still the case that virtually every popular treatment of some new press release about dating controversy in some ancient human habitation site (there's one every year or so) starts, as this article does, by talking about how it potentially nails the coffin for Clovis-First. (Wake up science writers! That coffin's been nailed shut for longer than most of your readers have been alive!)

[+] AlotOfReading|2 years ago|reply
You couldn't get from beringia to New Mexico during the last glacial maximum because of all glaciers in the way.

The dates given for the LGM are (very roughly) when Beringia was accessible from Siberia. Pinning down when humans were able to access the rest of the continent is tricky, but current estimates for that are sometime between 20-18kya at the earliest based on genetics. Dates based on material culture evidence are even later than that, which presents done obvious problems with the dating on these footprints.

There are also pretty hard constraints on the other side for humans even arriving in that part of Siberia, since the immediate ancestor sites with sequencing at Yana and Mal'ta are from 32kya and 25kya respectively.

[+] diogenes4|2 years ago|reply
I believe that "sometime between 26,500 and 19,000 years ago" is an appositive marking the beginning of the land bridge's accessibility, not the time of migration. What they should have said is that the broadly accepted conservative time frame for migration is somewhere between 14kya and 19kya, as the white sands footprints have dating issues that complicate accepting them at face value. The liberal interpretations of the evidence—especially in northern Canada and Alaska—can push evidence back to more than 33kya—I've seen dating for 44kya, iirc, which is very contentious and not broadly accepted.

That said I don't have a wapo subscription, so that's my best guess.

[+] fredgrott|2 years ago|reply
It was not the land bridge, it was the island chain below it as then with sea levels at it's lowest it would be easy to island hop and with the benefit of being able to island hop and follow food animal migrations.

Remember Kayak is an Inuit word...

[+] jcranmer|2 years ago|reply
Modern Inuit are descended from Thule culture, which spreads into the Arctic around 1100 CE. It's not clear when kayaks first develop; the oldest clear reference to one I can find involves a toy kayak dated to ~500CE in an Alaskan culture that probably influenced the Inuit.
[+] bagels|2 years ago|reply
Why do some of the feet seem to have four or six toes?
[+] codetrotter|2 years ago|reply
Well, relatedly:

The median number of legs for a human being is 2. The average is slightly less. So most people have an above average number of legs.

But also, footprints with just four toes could also be because of one of the toes not carrying enough weight to make a legible print.

[+] JKCalhoun|2 years ago|reply
There are petroglyphs depicting six-fingered hands in Chaco Canyon and, judging from an internet search, people can have six fingers.

Stands to reason six toes is possible?

[+] smegsicle|2 years ago|reply
will we ever find anything that humans haven't touched ???
[+] debatem1|2 years ago|reply
Pretty sure we haven't touched the sun and I find that almost every day.
[+] carapace|2 years ago|reply
There are vast portions of the North American continent that have never been visited by any human modern or ancient.