By Land or By Sea: A Reanalysis of the Peopling of the Americas Hypotheses

It is well understood by seasoned scholars of any discipline that the more we learn about a topic the more we realize that we actually know less and less.  The reason for this paradox is that research often brings about new research questions that must be answered, which is both good and bad.  This leads to further research but causes us to not truly understand the problem or topic we were initially seeking to solve or know.  One such situation is the case of archaeologists being perplexed over many decades on how specifically humans came to the New World (aka, the Americas).  Evidence existed and demonstrated human occupations across the New World at very different times, resulting in heated debate among scholars and outright refusal in some cases to believe the existing evidence, but with time comes greater advances in ways of studying the past and ultimately clarity.  Today’s blog post is going to discuss what we used to know versus what we now know regarding the peopling of the New World.

Figure 1: Clovis point

 

Archaeologists first stumbled upon the debate regarding the peopling of the New World when they tried to pin down the earliest human occupation in the New World.  Scholars had discovered significant evidence of material culture associated with what they called the “Clovis” culture (named after Clovis, New Mexico, where the original artifacts were found) (Figure 1).  The Clovis culture (or tradition) is a Paleoindian culture characterized by long, bifacial stone points that are also fluted on each side.  Several Clovis points had been found across North America, which validated the existence of humans in North America as early as 13,500 years ago.  Archaeologists believed that the Clovis people came to the New World by land through an ice-free corridor along the Bering land bridge, which was a large land mass that existed between Siberia (in Asia) and Alaska (in North America) that today is islands but was not in the past (Figure 3).  When these people were faced with the land being too icy and covered in massive glaciers these migrants were forced south into the modern day southern United States, which is where their remains were eventually found (and these glaciers may be why we do not find their artifacts in northern parts of North America).  Archaeologists were very comfortable with this idea given the abundance of Clovis materials they found throughout North America, and while they did not have additional evidence to back up their ideas this notion of an ice-free corridor seemed the most solid and most supportable and it came to be believed as truth.    

 

Figure 2: Meadowcroft Rockshelter

This all began to change when other evidence slowly started to chip away at this idea.  Evidence of earlier human occupations at several North American sites, including Meadowcroft Rockshelter in Pennsylvania (Figure 2), Topper Site in South Carolina, Cactus Hill in Virginia, Page-Ladsen in Florida, and Paisley Cave in Oregon, as well as the site of Monte Verde in Chile, told a different story, a much earlier one of human occupation of the New World.  This made many scholars very uncomfortable, particularly given the geographical distance among all these sites and what knowledge they had regarding the climate of those periods, which was considered glacial (meaning very icy) and too inhospitable for human occupation.  Many archaeologists refuted these pieces of evidence, claiming that they were not really human occupation sites or the dates coming from the sites were incorrect.  Despite these criticisms, though, scholars kept working, believing that someday they would truly know and understand when humans first settled the New World. 

As luck would have it those scholars’ patience paid off.  With advances in paleogenetic studies scholars were able to test biological remains of humans (and animals, as applicable) to determine when and where the first human migrants may have come from.  Additionally, advances in paleoclimatic studies allowed scholars to reconstruct what the environment may have looked like in the past.  Paleogenetic studies demonstrated that human occupations came from the Asian continent, which supported previous notions, but that these migrations actually came much earlier than expected, with liberal estimates claiming 30,000 years earlier than originally thought (although conservative results demonstrate migration occurring about 5,000 years earlier than originally estimated).  Paleoclimatic studies further revealed that an ice-free corridor either did not exist or that it was not hospitable enough to allow for human migration to have occurred to support the notion that the Clovis people were the original migrants to the New World.

Figure 3: Hypotheses pertaining to the Peopling of the New World

 

Begrudgingly (for some), scholars began to admit that they may have been too quick to conclude that an ice-free corridor was the only means of coming to the New World.  An additional hypothesis that had originally been entertained although quickly dismissed was now once again available to pursue.  This hypothesis puts forward the idea that human migration did not occur over land but by sea (Figure 3), and that early peoples traveled along the coasts of the Americas to seek suitable places to land and explore the continents.  Unfortunately, as it was then and remains today it is difficult to test this hypothesis fully since the coast lines these early migrants would have originally settled are underwater and the artifacts associated with their early sites most likely lost given the poor preservation conditions of the oceanic waters.  Despite this lack of evidence the strength of the evidence regarding the lack of free and traversable land through the Bering land bridge does demonstrate strong support for the coastal migration model.  Perhaps as new advancements in technology and scientific analyses occur we may be able to further and more fully explore the coastal migration model.  Until then, we will just have to wait and see.

References

Arnaiz-Villena, A.; C. Parga-Lozano; E. Moreno; C. Areces; D. Rey; P. Gomez-Prieto.  2010.  2010.  “The Origin of Amerindians and the Peopling of the Americas According to HLA Genes: Admixture with Asian and Pacific People.”  Current Genomics 11: 102-114.

Curry, Andrew.  2012.  “Ancient Migration: Coming to America.”  Nature 485: 30-32.

Kamrani, Kambiz.  2008.  “Peopling of the Americas: Three Step Model for Colonizing the Americas.”  Blog Post.  Anthropology.net

 

Kitchen, A., Miyamoto, M.M., Mulligan, C.J., Harpending, H. (2008). A Three-Stage Colonization Model for the Peopling of the Americas. PLoS ONE, 3(2), e1596

Klein, C.  2016.  “New Study Refutes Theory of How Humans Populated North America.”  History in the Headlines.  History.com

 

No Author.  No Date.  “Other Migration Theories – Bering Land Bridge National Preserve.”  Bering Land Bridge National Preserve Alaska.  Government Website.

 

No Author.  2015.  “The Peopling of the New World.”  Archaeology Magazine.  Archaeological Institute of America.

Schurr, T.  2000.  “Mitochondrial DNA and the Peopling of the New World.”  American Scientist May-June 1-10.

  

Schurr, Theodore G.  2004.  “The Peopling of the New World: Perspectives from Molecular Anthropology.”  Annual Review of Anthropology.  33: 551-583.