Humans lived in what is now Mexico up to 33,000 years ago and may have settled the Americas by travelling along the Pacific coast, according to two studies by myself and colleagues published today.
It has been commonly believed that the first people to enter the Americas were big-game hunters from Asia, who arrived after the last Ice Age around 13,000 years ago. This narrative is known as the “Clovis first” theory, based on distinctive stone tools produced by a people archaeologists call the Clovis culture.
For most of the 20th century, this theory was widely accepted. However, more recent archaeological evidence has shown humans were present in the Americas before the Clovis people.
Just how much earlier, however, is unclear and a topic of intense academic debate.
Read more: Ancient DNA in lake mud sheds light on the mystery of how humans first reached America
What we found in Chiquihuite Cave
Chiquihuite Cave is an archaeological site more than 2,740 metres above sea level in Zacatecas, Mexico. Ciprian Ardelean of the University of Zacatecas has been leading excavations of the site for more than seven years. Nearly 2,000 stone tools and pieces created through their manufacture have been found.
The tools belongs to a type of material culture never before seen in the Americas, with no evident similarities to any other cultural complexes. Importantly, more than 200 specimens were found below an archaeological layer that corresponds to the peak of the last Ice Age. (Archaeologists call this peak the Last Glacial Maximum.)
During this time, between 26,000 and 19,000 years ago, ice sheets were at their greatest extent. Evidence from Chiquihuite Cave, therefore, strongly suggests that humans were present in North America well before Clovis.
Given the significance of the discovery, myself and a team of international researchers joined in the interdisciplinary study of Chiquihuite Cave. Some of us had the opportunity to visit the site following a four-hour long journey by foot, and see the evidence at first hand. Our aims were to reconstruct the environment humans lived in and define exactly when they occupied the site.
My own research at Chiquihuite Cave focused on the latter. I helped to build a chronology of more than 50 radiocarbon and optical dates.
Combined with the archaeological evidence, the results showed humans inhabited Chiquihuite as early as 33,000 years ago, until the cave was sealed off at the end of the Pleistocene period (around 12,000 years ago).
The pattern of settlement
In a second paper, I explore the wider pattern of human occupation across North America and Beringia (the ancient land bridge connecting America to Asia). This involved analysing hundreds of dates obtained from 42 archaeological sites in North America and Beringia, including Chiquihuite Cave, using a statistical tool called Bayesian age modelling.
The analysis showed there were humans in North America before, during and immediately after the peak of the last Ice Age. However, it was not until much later that populations expanded significantly across the continent.
This occurred during a period of climate warming at the end of the Ice Age called Greenland Interstadial 1. The warming began suddenly with a pulse of increased global temperature around 14,700 years ago.
We also observed that the three major stone tool traditions in the wider region started around the same time. This coincides with an increase in archaeological sites and radiocarbon dates from those sites, as well as genetic data pointing to marked population growth.
This significant expansion of humans during a warmer period seems to have played a role in the dramatic demise of large megafauna, including types of camels, horses and mammoths. We plotted the dates of the last appearance of the megafauna and found they largely disappeared within this, and a following, colder period.
However, the contribution of climate change in faunal extinctions, represented by abrupt warming and cooling, cannot be fully excluded.
The first human arrivals came from eastern Eurasia, yet it looks as though there was a surprisingly early movement of people into the continent.
We think the path of earlier arrivals to these new lands was probably along the coast. Inland travel would have been blocked, either because Beringia was partly underwater or because modern-day Canada was covered by impenetrable ice sheets.
Together, the two studies and their results depart from previously accepted models, and allow us to uncover a new story of the initial peopling of the Americas. This journey, marking one of the major expansions of modern humans across the planet, will continue to mystify and spark debate.
Lorena Becerra-Valdivia, Postdoctoral Research Fellow, UNSW
This article is republished from The Conversation under a Creative Commons license. Read the original article.
HT/Matt E
Very interesting article and comments.
I began what I thought would be a simple task a few years ago for my book–how old is the spinning wheel? While some may just turn that out of hand and pass it off as unimportant, it really isn’t and here is why:
Origins to the original spinning wheel are lost. There is a picture of a spinning wheel in a Chinese carving dating to about 400BC, or is it? Is it? There are those that say yes, there are those that say no. Yet a relatively short time after that carving is dated (perhaps incorrectly) India starts big in the cotton and silk trade. But Sericulture (silk) was a secret in China at the time…so how did India get it? More over, how did they “spin” it (spin is in quotes as silk isn’t spun, it’s plied monofiliment to be base)…and better yet, what was India doing until then? Fast forward and the first picture of a spinning wheel in Germany is 1400. That’s 1000+ years later. Well how did it get there and looking so modern we would recognize it as a spinning wheel?
I use this as an example of something as vital to human society as a spinning wheel and we can’t even date it. We don’t know who invented it. We don’t know where it came from and we don’t know how it got to Europe. It just “appeared”. The more you dig, the more you realize we don’t know and push the boundaries into the unknown.
So…could humans have expanded their world knowledge as early as 35K years ago? Why not? What makes ancient human less inquisitive about their world than us? What makes them less observant or “scientific” as us? Or less curious? And why not earlier? Like the spinning wheel’s appearance in Europe, it didn’t just ‘happen’ one day that a monk decided to record it in a book that survived. There is a long, long history that represents it’s appearance for posterity. I’m still searching for that history–which may be lost under the ocean until it recedes and can be found again….or it may be buried in some accounting book left unlooked at after all these thousands of years. Some trade manifest still unstudied. The point is that we don’t know…until we do.
Spinning wheel was most likely invented in India before AD 1000.
China in 400 BC is very unlikely. Probably a misinterpretation or misdating of the carving.
I think it is about time that science gets rid of the blinders and start to give at least some attention to a number of scientists who have been saying for well over fifty years, that a human presence in the Americas dates back to 200,000 to 250,000 BP. Virginia Steen McIntyre one of the main people at the Pleistocene Coalition website, has been convinced that very old artifacts have been unearthed at Valsequillo in Central Mexico, and the other at Calico in the southwest U.S. And the eminent archeologist, Richard Leakey, after examining some of the Calico artifacts conservatively admitted, as he believed the finds may well have been much older, that the artifacts were at least forty to fifty thousand years old. Why don’t reputable scientists like you Charles Rotter, give some credit to those brave souls before you that have already indicated that early man in some capacity was in the Americas for a very long time ago. And to even mention the Paul Martin’s hypothesis, pardon me but this theory should have been place in the trash bin where it belongs. It is a joke to even mnetion this outdated theory.
Re. Calico Hills, Mary Leakey ultimately left her husband over their disagreement on his loss of scientific respect.
The alleged “artifacts” were promptly recognized as geofacts. Papers by Duvall and Venner, Payen and others provided natural explanations for the putatively man-made stone objects.
Furthermore, the lack of other evidence of human activity, eg human or animal remains, or non-tool artifacts, showed the “site” to be geological, not archaeological. This concljusion was reinforced by the sheer number of ostensible “tools”, up to 60,000.
There is not only no evidence of humans in North America 250,000 years ago (date suggested for Valsequillo tools), but none in northern Siberia (57 N) before 45 Ka, and that just east of the Urals. In Europe 200 Ka, there were sparse on the ground Neanderthals.
Sadly, Leakey did embarrass himself with a gross error.
The Valsequillo tools were far too sophisticated to have been made anywhere on Earth 250 Ka, even Africa. They were associated with animals which didn’t live there before the LGM. The dating was simply off by an order of magnitude.
It is however a possibly Pre-Clovis site.
Everyone who is alive and has ever been alive is a result of events going back as far as there have been humans.
The truth about this has been limited by social correctness over science.
I will try to find the book Vikings of the Sunrise.
http://nzetc.victoria.ac.nz/tm/scholarly/tei-BucViki.html
Remember; while absence of evidence is not evidence for absence, it is still just that. Like yeti and alien visitors, there is a general absence of evidence for humans in the Americas prior to 40,000 ybp.
The presence of humans in the “new world” prior to 20,000 ybp is the subject of legitimate scientific debate. Debate over whether the evidence stands scrutiny, whether we’re looking hard enough, whether we’re looking in the right places and whether we are biased in our judgements.
There have been some additional archeological finds from Southern California by other researchers that have been dated to about 130,000 BP, well before the date you cite (John Tillman) of 60,000 BP. I also suggest, why did the earliest people have to come from Siberia? There are many others theories including, yes, early arrivals from Europe, or even Polynesia. And what makes you think Mary Leakey was correct, she may have been wrong just as easily as her husband. And also, they were and are several experts besides, Virginia Steen McIntyre that have provided their evidence to the Pleistocene Coalition News.
Mary was correct and her husband wrong.
There is zero valid evidence of humans in the New World at 130 Ka. There were no modern humans then outside of Africa, so no possibility of trans-Pacific voyages from Asia.
Science requires evidence. Wild speculation doesn’t count.
John: I will give you the benefit of the doubt re: Mary, but I think if her husband was incorrect, then scientists at the Pleistocene Coalition should have indicated this and to my knowledge they have not. Why, like the original native people in the Americas continue to contend that they are from here? Don’t you think it possible that their arrival was a very long time ago? The i30,000 BP figure was from an independent study not far from San Diego. I will dig up (excuse the pun) the reference if you are interested? Also, the Neanderthals were present in Europe as long ago as 250,000 BP., and according to scientists Dimitra Papagianni and Michael Morse they present in their quite recent book (2015), information indicating that the Neanderthal were much more developed than given credit, just a few years prior to the mid 2010’s. Is it so difficult to believe that they not only arrive in Europe about 250,000 BP, but also made into the Americas by boats?
All of the possibilities you can imagine founder for lack of evidence. The San Diego site is fanciful at best, you can draw no conclusion from that.
A pre-Clovis culture in the Americas appears to be certain, although even there, each site has issues in their pre-Clovis elements.
No credible evidence exists for pre-Columbian influence in the Americas from Europe, except a failed colonization attempt in the Northeast from Greenland during the MWP.
John T.,
Ancient documents, including those revered by world religions, can contain reflections of historic events. The legendary argonauts sailed from Crete into the very real eruption at Thera (Argonautica, Appolonius of Rhodes, Book 4). But they didn’t really spill the blood of the iron man who circled Crete protecting it from invasion on the way.
Genesis carries a record of a “world”-shattering flood, probably one of many that occurred as the oceans refilled. But if “Noachian” means with the Ark and the animals and all that, then you’re correct. Thats a no.
Correction: χαλκειός is bronze, not iron.
Congratulations on taking part in this incredible study. I have to admit that I don’t know very much about this subject. After a trip to Washington state 2 years ago, I heard about “Kennewick man”and I became interested. What would you suggest reading for most accurate/ up to date information and where does “Kennewick man” fit into all this ? TY. Great site, btw.
“This significant expansion of humans during a warmer period seems to have played a role in the dramatic demise of large megafauna, including types of camels, horses and mammoths. We plotted the dates of the last appearance of the megafauna and found they largely disappeared within this, and a following, colder period”
This is close to an outright claim of causation. As such, it should have been accompanied by a chain of logic and facts. Absent those, and with a huge common-sense contra-indication, it is a credibility-destroying paragraph. You should have stopped short of that claim.
Here’s the common sense. There were millions and millions of huge beasts across The Americas. Homo sapiens numbers were small. Tiny. Just a few communities, at best. (large population came later). Homo had no horses to chase millions and millions of huge beasts. No metalcraft — nothing but stone and bone tools. Even evidence of atlatls, a spear-leverage weapon, is skimpy and full of speculation.
The small population of Homo in the North America 33,000-12,000 years ago did not drive the Mega Fauna into extinction.
I agree whole heartedly with you windlord-Sun