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the archaeology community is buzzing
about two new scientific studies that
challenge what we thought we knew about
the first humans in the americas these
studies were both published in the
journal nature on july 22nd
and they provide surprising evidence
that people were on this land mass some
10 to 15 000 years
earlier than archaeologists previously
thought which as they say
is big if true for a long time the
oldest evidence we had of humans in the
americas were artifacts dating to around
13 000 years ago these are attributed to
a group of humans called the clovis
people who traveled from modern-day
russia to the northwest tip of north
america via a bridge of land that used
to exist
when sea levels were lower but in recent
decades evidence has been popping up
that suggests
humans were here even earlier than that
but exactly how much earlier has been
the big question and a source of
heated debate the authors of the two new
studies have leapt headfirst into this
controversy by claiming that people have
lived in the americas for at least 30
000 years though they would have taken
the same bridge that could mean they
took
a different route to south america or
across the continent
so maybe we've been looking in all the
wrong spots for evidence of early
peoples and it could have major
implications for how we interpret the
effects of our species
like how these early people impacted
local wildlife
depending on whether they arrived before
or after key extinctions
the researchers arrived at that 30 000
dish figure using two different kinds of
evidence the first is your classic
archaeological study
they report stone tools from chicawite
cave in the mountains of northern mexico
which date back that far
a team of dozens of international
scientists carefully excavated and
examined three meters of layered
sediment
containing over 1900 angular pieces of
limestone and they believe that
based on the shapes and wear on these
stones they're bona fide human-made
tools
even though they're different from the
tools of every other ancient culture
that we know of and using a combination
of dating techniques
the researchers found that some of the
sediment layers containing these objects
are 30 000 years old that would mean
that not only had humans made it to
north america by that time
they had already spread all the way down
into mexico this
clashes with most accepted
archaeological evidence but is totally
in line with the results of the second
new study which comes from two of the
first studies authors
in this one the pair compiled
information from 42 archaeological sites
to create a statistical model that makes
predictions about how
people spread across the continent and
what's interesting is that this model
suggests a similar narrative
that humans were likely in north america
26 000 years ago and
possibly earlier but extraordinary
results tend to receive intense scrutiny
from other scientists and that's
definitely happening here
one major sticking point is the nature
of the quote stone tools
some experts aren't convinced that
that's what they are it can be difficult
to tell a rock that's been broken
intentionally by humans from a rock that
was damaged by more mundane things
like the collapse of a cave ceiling
though in this case the stones had to
have come from outside the cave as the
kind of stone didn't match the cave
itself but still they could have washed
in during a flood or
something like that so critics say the
authors haven't provided enough evidence
against that kind of non-human
explanation
but the authors say the tools speak for
themselves additionally while the
authors of the new study identify the
cave as a human dwelling place
other experts don't think the evidence
supports that conclusion they haven't
found human remains or even dna for
instance
the authors say that's because the cave
wasn't a permanent home
it was probably more of a last-ditch
shelter perhaps used every few decades
during really harsh winters given how
difficult it can be to identify sites
like this
and how important they are to our own
history disputes like this
are not unusual similar sites in south
america have alleged to have evidence of
humans from over 20 000 years ago
and they too were questioned some
experts have pointed out that these
sites tend to be highly disputed or even
ignored by many archaeologists
simply because they don't fit the more
accepted story and evidence but to be
fair the evidence they provide
isn't as clear-cut and their
controversial nature
might be a source of trouble for that
second statistical study you see outside
experts have pointed out that some of
the archaeological sites used in the
model
are disputed in terms of their age or
the identification of their artifacts
indeed the chicawite cave is one of the
sites used and if these places don't
turn out to be sites where ancient
humans were then the model itself and
its intriguing results
might also be flawed if there's one
thing everyone agrees on though it's
that all of this is worth investigating
further if humans really were in the
americas 25 plus thousand years ago then
more investigation of these super old
sites should reveal
more conclusive evidence and there
should be other as of yet undiscovered
sites that can give us a better idea of
when
where and how humans were making their
way across this hemisphere
so while it might seem like our
understanding of the past is kind of a
mess
it's important to keep in mind that this
is how science works pretty much
everything we know about this planet and
how we got to where we are today was
once a wild idea that challenged the
status quo of course there also have
been lots of wild ideas that didn't pan
out so without more data we can't be
sure whether the idea of 30 000 year old
north american people is a game changer
or not so as is so
often the case in archaeology clearer
answers are waiting to be dug up
thank you for watching this episode of
scishow news and an extra thank you to
today's president of space harrison
mills
we checked and the evidence is
incontrovertible you're awesome harrison
and so are our other patrons on patreon
we are so lucky to have such an engaged
science loving community that supports
scishow if you'd like to learn more
about that community or how you could
become president of space like harrison
you could head over to patreon.com
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