
Cave discoveries suggest humans reached Americas much earlier than thought - pseudolus
https://www.nature.com/articles/d41586-020-02190-y
======
sradman
From the linked Wikipedia article on Beringia [1]:

> Today, the average water depth of the Bering Strait is 40–50 m (130–160 ft),
> therefore the land bridge opened when the sea level dropped more than 50 m
> (160 ft) below the current level. A reconstruction of the sea-level history
> of the region indicated that a seaway existed from c. 135,000 – c. 70,000
> BP, a land bridge from c. 70,000 – c. 60,000 BP, intermittent connection
> from c. 60,000 – c. 30,000 BP, a land bridge from c. 30,000 – c. 11,000 BP,
> followed by a Holocene sea-level rise that reopened the strait.

30-25 kya fits the data OK and there may have been open north-south corridors
at that time. The question is how solid the Mexican evidence is.

[1]
[https://en.m.wikipedia.org/wiki/Beringia#Geography](https://en.m.wikipedia.org/wiki/Beringia#Geography)

~~~
simonh
It seems like there are other bits of evidence of pre-clovis human habitation,
but taken individually they could be dismissed as due to some sort of
misidentification, contamination of the site, etc. One the other hand this
site seems to have very extensive evidence of long term habitation, backed up
by several independent but mutually consistent dating methods. Add back in all
those 'one off' finds as well and the clovis first theory starts to really
break down.

~~~
34679
I've been fascinated by this one since visiting the Natural History Museum in
San Diego:

"A 130,000-year-old archaeological site in southern California, USA"

[https://www.nature.com/articles/nature22065](https://www.nature.com/articles/nature22065)

~~~
sradman
Interesting. MIS5e [1] would be a parallel to our current interglacial period.
I think the evidence for 50-60 kya out-of-africa event for Homo sapiens is
solid so I'm assuming this site would support the global reach of another Homo
species like Neanderthals.

[1]
[https://en.wikipedia.org/wiki/Marine_Isotope_Stage_5](https://en.wikipedia.org/wiki/Marine_Isotope_Stage_5)

~~~
irrational
I’ve never understood that number. I’ve read that modern humans have been
around for 200k years, but I’m supposed to believe that for 3/4 of that time
they stayed in Africa? BS. Maybe proof hasn’t been found, yet. But we know
from our own experience that modern humans love to explore. I don’t believe
that love of travel and adventure and exploration is cultural. Our modern
ancestors would’ve been exploring out of Africa long before 50kya.

~~~
Zaak
There's an important distinction between anatomically modern humans and
behaviorally modern humans. Behaviorally modern humans were the ones that were
able to migrate all over the world.

[https://en.wikipedia.org/wiki/Behavioral_modernity](https://en.wikipedia.org/wiki/Behavioral_modernity)

------
api
Look at Göbekli Tepe as well. The general trend seems to be pushing human
history back, which makes sense as the human species has existed in its near
modern form for quite a bit longer than the history we know. There is no
reason to believe these ancient humans lacked critical cognitive faculties
that we have.

From what I've read of the debate on humans in North and South America, it
seems that both sides are ignoring the possibility of multiple colonizations
and that earlier colonizations may have either failed entirely or resulted in
only very small populations in limited areas.

If genetic evidence suggests that Native Americans are descendants of a stock
that migrated here around 10K years ago, maybe they were just a later
migration that really "took" and expanded across the whole land mass (until
Europeans).

Or maybe the newcomers or their diseases exterminated the existing indigenous
peoples? Maybe the story of the last colonization of these lands has occurred
multiple times? If so, we're really screwed when the extraterrestrials arrive.

------
mehrdadn
Question: how do experts tell something like this might be a tool? As a layman
it looks like a rock to me:

[https://media.nature.com/lw800/magazine-
assets/d41586-020-02...](https://media.nature.com/lw800/magazine-
assets/d41586-020-02190-y/d41586-020-02190-y_18201476.jpg)

~~~
DanBC
I think they look for "Conchoidal fractures", and then where they find the
thing.

[https://www.sandatlas.org/conchoidal-
fracture/](https://www.sandatlas.org/conchoidal-fracture/)

~~~
AlotOfReading
Not always, but it's one of the common indicators. The general process for
survey identification goes like this: you walk around looking at the ground
and notice the _unnatural_ ones. This is a purely intuitive sense, so you pick
one up and look closer to see that yep straight edges, conchoidal fractures,
common material, found in a bed with other clear lithics, etc. Bag and tag.

------
walrus01
An interesting question related to this is the exact time period of the "last
glacial maximum", at which point in time northern latitude glaciers were at
their maximum extent, and sea levels were considerably lower. Related to the
Bering strait land bridge.

[https://en.wikipedia.org/wiki/Last_Glacial_Period](https://en.wikipedia.org/wiki/Last_Glacial_Period)

[https://en.wikipedia.org/wiki/Last_Glacial_Maximum](https://en.wikipedia.org/wiki/Last_Glacial_Maximum)

If the claim of 30,000 years is true (vs 11,000 years) this would mean people
crossed the Bering strait at a time when the terrain was different, or
possibly even when it was submerged.

[https://en.wikipedia.org/wiki/Beringia](https://en.wikipedia.org/wiki/Beringia)

~~~
brohee
Hoping along the Commander Islands, Near Islands then Aleutian Islands chain
from Kamchatka was likely possible with primitive tech. And those places must
have been hunting paradises to neolithic people so reasons to settle them.

~~~
ncmncm
Humans made it to Australia without any Land Bridge. Island hopping is
completely plausible: once you have crossed one waterway, the next is easier.

We know that populations of humans subsisted on coastal shellfish 50kya. There
is no reason to assume they stayed at one place on a coast that had shellfish
everywhere along it.

Of course all those shell middens are now 30-50m below sea level.

If there is an Atlantis, that is, too, for identically the same reason,
although the timing would differ. It would be hard to credit an Atlantis
originating before, say, 12,000 years ago--sometime in the Younger Dryas cold
spell--although up to 20,000 years ago is conceivable.

~~~
catalogia
> _Humans made it to Australia without any Land Bridge._

For that matter they also made it to Hawaii without any land bridges.
Polynesian navigators and sailors proved that neither land bridges nor high
technology are needed for these sort of daring ocean crossings. Who is to say
that other early seafaring cultures couldn't have accomplished similar feats?

~~~
brohee
The Pacific settlement happened much later (during European middle age for
Hawaii), benefiting from 40000 year of technological improvement...

~~~
catalogia
What specific technology are you referring to? I'm unaware of any Polynesians
technology that couldn't plausibly been independently used tens of thousands
of years earlier. The accomplishments of the Polynesians seafarers was
primarily a matter of skill and oral tradition (something like 4,000 years of
seafaring experience, not 40,0000.)

Their most important technology was sea-worthy outrigger canoes. Numerous
independent canoe cultures exist around the world dating back thousands of
years ago. While canoes 40,000 years old haven't been found, I see no real
reason to discount the possibility. For navigation they may have used stick
charts, although that's not known for sure and the Polynesians may have relied
on oral tradition instead. Either way, these technologies or their functional
equivalents were plausibly available to cultures predating the Polynesians by
thousands of years. There is no evidence that the Polynesians were using
astrolabs, sextants, or any other instrument like that, so the relative level
of technology used by contemporary European/Islamic/Classical navigators
doesn't seem relevant. They used Mark 1 Eyeballs to collect information and
processed that information into navigational guidance using their brains,
packed with experience.

Edit: I've been thinking about the matter of canoes some more. It seems to me
that sea-fairing canoes would not preserve well; the earliest known canoe is
from around 10,000 years ago and was found in a peat bog in the Netherlands.
Peat bogs are well known for preserving buried organic matter. Conversely the
oldest polynesian canoes found are only hundreds of years old. We know they
were using canoes thousands of years before that because of their oral
tradition and clear evidence that they were traveling in the area _somehow_
during that time period, but archeological evidence for the boats is scarce. I
don't think sea-fairing canoes are likely to be preserved for thousands of
years, so I don't think the lack of archeological evidence for sea-fairing
cultures thousands of years ago means much of anything.

[https://en.wikipedia.org/wiki/Pesse_canoe](https://en.wikipedia.org/wiki/Pesse_canoe)

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205625/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205625/)

~~~
brohee
The main one is the outrigger canoe, but celestial navigation must have taken
a while to master too. The earliest examples of astronomy come way later than
40000 year ago...

~~~
catalogia
This sort of astronomy used eyeballs and oral tradition. What archeological
traces would that leave?

~~~
ncmncm
It has left traces in stoneworks all over the world. But many of them may be
old enough; usually we have no way to discover how old one is.

------
mcswell
The picture in the article is of an alleged limestone tool; it looks like the
tool was shaped like a scraper or cutter of some sort, and is fairly small.
But afaik, no one ever made scrapers or cutters out of limestone; that rock is
far too soft. They were preferentially made of flint, but in regions where
there wasn't flint, obsidian or quartz could substitute for smaller tools, and
hard metamorphic or igneous rocks for larger tools (axes).

But surely an archeologist would not make such a mistake. So is my assumption
about the uselessness of limestone for cutting tools wrong?

~~~
simonh
Googling for limestone stone tools came up with plenty of hits, like this one.

[https://indianexpress.com/article/technology/science/mysteri...](https://indianexpress.com/article/technology/science/mysterious-
stone-tools-discovered-in-the-uk-4882247/)

This article shows a much more comprehensive collection of tools from
Chiquihuite.

[http://www.sci-news.com/archaeology/stone-tools-
chiquihuite-...](http://www.sci-news.com/archaeology/stone-tools-chiquihuite-
cave-mexico-08667.html)

~~~
mcswell
Thanks, but I'm still skeptical.

The first article, in an Indian news site (and reproduced in several similar
sites) is about some stones that a group of amateur archeologists found. It
doesn't appear to have been published in any professional journal, and the
comments make it clear that these are unlike anything seen elsewhere, and
their purpose is unknown. My guess: they're not tools, they're random rocks.

The other article, as you point out, shows a greater variety of the alleged
tools from Chiquihuite. I'm no archaeologist, but to me they look like rocks
that were carefully chosen out of a bunch of randomly shaped rocks. The
picture of the cave entrance show that it is full of breakdown (caver for
"rocks that fell off the ceiling of the cave"), and I wouldn't be surprised to
discover things that look sort of like blades or points in such a pile of
rocks.

So I'm afraid I'm still skeptical.

