Oldest human footprints in New World

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jillery

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Sep 25, 2021, 4:00:11 AMSep 25
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<https://www.msn.com/en-us/news/us/stunning-footprints-push-back-human-arrival-in-americas-by-thousands-of-years/ar-AAOKBoq?li=BBnbfcL>

<https://tinyurl.com/74saur9u>
*********************************
According to a paper published today in the journal Science, the
footprints were pressed into the mud near an ancient lake at White
Sands between 21,000 and 23,000 years ago, a time when many scientists
think that massive ice sheets walled off human passage into North
America.
*********************************

Here's a link to the abstract of the cited paper:
<https://www.science.org/doi/10.1126/science.abg7586>
*********************************
Here, we present evidence from excavated surfaces in White Sands
National Park (New Mexico, United States), where multiple in situ
human footprints are stratigraphically constrained and bracketed by
seed layers that yield calibrated radiocarbon ages between ~23 and 21
thousand years ago. These findings confirm the presence of humans in
North America during the Last Glacial Maximum, adding evidence to the
antiquity of human colonization of the Americas and providing a
temporal range extension for the coexistence of early inhabitants and
Pleistocene megafauna.
**********************************

This date is thousands of years earlier than the dates suggested by
Clovis stone tools of about 12K years BP, and closer to even eariler
dates of at least 32K years BP of Pedra Furada sites in Brazil.

The region is a high basin completely surrounded by the San Andres and
Sacremento Mountains deep in the American Southwest. Although the
past climate almost certainly was wetter and milder than the present,
I can only imagine what would motivate someone to walk hundreds of
miles to go there.

--
You're entitled to your own opinions.
You're not entitled to your own facts.

RonO

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Sep 25, 2021, 8:30:10 AMSep 25
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On 9/25/2021 2:56 AM, jillery wrote:
> <https://www.msn.com/en-us/news/us/stunning-footprints-push-back-human-arrival-in-americas-by-thousands-of-years/ar-AAOKBoq?li=BBnbfcL>
>
> <https://tinyurl.com/74saur9u>
> *********************************
> According to a paper published today in the journal Science, the
> footprints were pressed into the mud near an ancient lake at White
> Sands between 21,000 and 23,000 years ago, a time when many scientists
> think that massive ice sheets walled off human passage into North
> America.
> *********************************

The Glacial maximum was 25,000 years ago. For some reason they want
there to be an open corridor on land between ice covered landscapes.

Inuits have made it across ice sheets to Greenland. You probably have
to be able to kill enough seals or fish on the sea ice to survive the
crossing, but my guess is that humans could have crossed any time during
the last glacial period. It would not have been easy, but humans can
obviously do it. The warm and cold periods have been about the same for
the last 5 ice ages, and the ice ages have been on their 100,000 year
cycle for the last million years.

>
> Here's a link to the abstract of the cited paper:
> <https://www.science.org/doi/10.1126/science.abg7586>
> *********************************
> Here, we present evidence from excavated surfaces in White Sands
> National Park (New Mexico, United States), where multiple in situ
> human footprints are stratigraphically constrained and bracketed by
> seed layers that yield calibrated radiocarbon ages between ~23 and 21
> thousand years ago. These findings confirm the presence of humans in
> North America during the Last Glacial Maximum, adding evidence to the
> antiquity of human colonization of the Americas and providing a
> temporal range extension for the coexistence of early inhabitants and
> Pleistocene megafauna.
> **********************************
>
> This date is thousands of years earlier than the dates suggested by
> Clovis stone tools of about 12K years BP, and closer to even eariler
> dates of at least 32K years BP of Pedra Furada sites in Brazil.
>
> The region is a high basin completely surrounded by the San Andres and
> Sacremento Mountains deep in the American Southwest. Although the
> past climate almost certainly was wetter and milder than the present,
> I can only imagine what would motivate someone to walk hundreds of
> miles to go there.
>

Like I indicated above the sea levels have dropped and the ice sheets
have extended to about the same extent for the last 5 ice ages (over
half a million years). Humans likely had to only wait until the
technology was developed to allow them to make the crossing. If we can
get ancient DNA what we might find is that if there were humans here in
the Americas 32,000 years ago that they didn't make it. Small bands may
have made it over, but they may have never estabilished successful
populations. Inbreeding depression and the changing environment (the
glacial max wouldn't occur until 25,000 years ago) could have done them
in before more successful migration events occurred.

Unless they were living on the sea ice there likely were no humans
living around Tierra del Fuego during the glacial max 25,000 years ago
because it was one big ice sheet.

Ron Okimoto

jillery

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Sep 25, 2021, 3:45:10 PMSep 25
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ISTM the earlier dates of anthropological sites in South America
suggests humans at least visited the New World long before glaciers
opened a land route across the Bering Sea. There are prehistoric
sites in Japan and the Philippines of at least 30K years BP, which
suggests humans had some ability to travel across at least small spans
of ocean by that time. Rather than going across the Pacific a la
Kon-Tiki, perhaps the first human visitors to the New World followed
the coastline southward in steps, without venturing inland.

RonO

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Sep 25, 2021, 4:05:10 PMSep 25
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The land bridges were supposedly not ice covered. They think that they
were open corridors. Things like horses, camels and bison got across
during ice ages that preceded the last one that modern humans
supposedely used to cross. It is one reason why you have to wonder why
we don't find Neanderthal and Denisovan remains in North America. If
the Bison made it over Homo could have followed them. They wouldn't
have had to pack supplies just follow the migrating herds.

Ron Okimoto

Bob Casanova

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Sep 25, 2021, 6:05:10 PMSep 25
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On Sat, 25 Sep 2021 15:01:26 -0500, the following appeared
in talk.origins, posted by RonO <roki...@cox.net>:
I lack more than layman's knowledge on this subject, but is
it possible that prior to H. sapiens big-game wasn't a large
part of whatever hunting was done? If that were the case
there wouldn't have been much incentive for earlier Homo
species to follow the game before the latest glaciation.

Of course, it's also quite possible that the population was
never very high, and we just haven't yet discovered whatever
remains might exist. Or that they spread out into formerly
glaciated areas during the subsequent interglacial and later
glaciations destroyed any evidence.
>
--

Bob C.

"The most exciting phrase to hear in science,
the one that heralds new discoveries, is not
'Eureka!' but 'That's funny...'"

- Isaac Asimov

Mark Isaak

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Sep 25, 2021, 6:05:10 PMSep 25
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My impression is that it is now almost a consensus among anthropologists
that the first New World immigrants did not trek inland, but followed
the coast in small boats.

--
Mark Isaak eciton (at) curioustaxonomy (dot) net
"The presence of those seeking the truth is infinitely to be preferred
to the presence of those who think they've found it." - Terry Pratchett

Bob Casanova

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Sep 27, 2021, 12:25:12 PMSep 27
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On Sat, 25 Sep 2021 15:00:44 -0700, the following appeared
in talk.origins, posted by Bob Casanova <nos...@buzz.off>:

Any thoughts on this, Ron?

RonO

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Sep 28, 2021, 9:00:12 PMSep 28
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Neanderthals ate rhinos and other big game. They did not have throwing
spears, but maybe they ran them off cliffs or something. Neanderthals
suffered a lot of broken bones. Some Anthropologists think that they
really did go for big game with thrusting spears. It may have been how
they were injured so often. I recall one paper comparing Neanderthal
broken bones to Rodeo injuries.

>
> Of course, it's also quite possible that the population was
> never very high, and we just haven't yet discovered whatever
> remains might exist. Or that they spread out into formerly
> glaciated areas during the subsequent interglacial and later
> glaciations destroyed any evidence.
>>

It could be that small bands persisted for a while after getting to
North America, but never sustained healthy populations. If only a few
small family groups made it across inbreeding depression could have done
them in. Think of European Royalty.

https://blog.23andme.com/ancestry-reports/inbreeding-doomed-habsburg/

Neanderthals existed in small inbred groups. They maintained a lot of
genetic diversity, but they did it by maintaining a lot of small family
groups. Inbreeding depression could be ameliorated as long as you had
neighbors that you could outcross with. The first family groups into
North America may not have had enough neighbors.

Ron Okimoto

jillery

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Sep 28, 2021, 9:15:12 PMSep 28
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On Tue, 28 Sep 2021 19:55:38 -0500, RonO <roki...@cox.net> wrote:

>It could be that small bands persisted for a while after getting to
>North America, but never sustained healthy populations. If only a few
>small family groups made it across inbreeding depression could have done
>them in. Think of European Royalty.


Neanderthals with a Hapsburg lip... oy.

Bob Casanova

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Sep 29, 2021, 1:00:13 AMSep 29
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On Tue, 28 Sep 2021 19:55:38 -0500, the following appeared
OK; thanks. As I said my knowledge is limited, and any info
is welcome.
>>
>> Of course, it's also quite possible that the population was
>> never very high, and we just haven't yet discovered whatever
>> remains might exist. Or that they spread out into formerly
>> glaciated areas during the subsequent interglacial and later
>> glaciations destroyed any evidence.
>>>
>
>It could be that small bands persisted for a while after getting to
>North America, but never sustained healthy populations. If only a few
>small family groups made it across inbreeding depression could have done
>them in. Think of European Royalty.
>
>https://blog.23andme.com/ancestry-reports/inbreeding-doomed-habsburg/
>
>Neanderthals existed in small inbred groups. They maintained a lot of
>genetic diversity, but they did it by maintaining a lot of small family
>groups. Inbreeding depression could be ameliorated as long as you had
>neighbors that you could outcross with. The first family groups into
>North America may not have had enough neighbors.
>
That's pretty much the sort of issues I was thinking of;
unless a species is fairly common the chances of it leaving
discoverable evidence is slight, although I'd think that any
living sites, especially if in caves or similar sheltered
areas, would be at least somewhat more likely to be
discovered that actual fossils.
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