The theory known as Clovis First was the predominant hypothesis among archaeologists in the second half of the 20th century to explain the peopling of the Americas. According to Clovis First, the people associated with the Clovis culture were the first inhabitants of the Americas. This hypothesis came to be challenged by ongoing studies that suggest pre-Clovis human occupation of the Americas. In 2011, following the excavation of an occupation site at Buttermilk Creek, Texas, a group of scientists identified the existence "of an occupation older than Clovis." At the site in Buttermilk, archaeologists discovered evidence of hunter-gatherer group living and the making of projectile spear points, blades, choppers, and other stone tools. The tools found were made from a local chert and could be dated back to as early as 15,000 years ago.
The primary support for this claim was that no solid evidence of pre-Clovis human habitation had been found. According to the standard accepted theory, the Clovis people crossed the Beringia land bridge over the Bering Strait from Siberia to Alaska during the ice age when there was a period of lowered sea levels, then made their way southward through an ice-free corridor east of the Rocky Mountains, located in present-day Western Canada, as the glaciers retreated.
According to researchers Michael Waters and Thomas Stafford of Texas A&M University, new radiocarbon dates place Clovis remains from the continental United States in a shorter time window beginning 450 years later than the previously accepted threshold (13,200 to 12,900 BP).
Since the early 2010s, the scientific consensus has changed to acknowledge the presence of pre-Clovis cultures in the Americas, ending the "Clovis first" consensus.
Alternatives to Clovis First Evidence of human habitation before Clovis
There have been a great number of archaeological findings across the Americas that pre-date the arrival of humans prior to 11,500–11,000 uncalibrated years before present (YBP). The Buttermilk Creek Complex, located in Salado, Texas, is a site where over 15,000 artifacts have been found. These artifacts are composed of a variety of small stone tool assemblages. These artifacts stratigraphically underlie previously excavated Clovis assemblages, meaning that they were deposited prior to the Clovis artifacts. These pre-Clovis assemblages are dated to between 13,200 and 15,500 years ago.
Predecessors of the Clovis people may have migrated south along the North American coastlines, although arguments exist for many migrations along several different routes. (Abstract) Radiocarbon dating of the Monte Verde site in Chile places Clovis-like culture there as early as 18,500 to 14,500 years ago. Remains found at the Channel Islands of California place coastal Paleoindians there 12,500 years ago. This suggests that the Paleoindian migration could have spread more quickly along the Pacific coastline, proceeding south, and that populations that settled along that route could have then begun migrations eastward into the continent.
The Pedra Furada sites in Brazil include a collection of rock shelters, which were used for thousands of years by diverse human populations. The first excavations yielded artifacts with carbon-14 dates of 48,000 to 32,000 years BP. Repeated analyses have confirmed this dating, carrying the range of dates up to 60,000 BP.Guidon, Niède. (1986) Las Unidades Culturales de Sao Raimundo Nonato – Sudeste del Estado de Piaui-Brasil; New Evidence for the Pleistocene Peopling of the Americas: 157–171. Edited by Alan Bryan. Center for the Study of Early Man. University of Maine. Orono. Among the best analyzed archaeological levels are those dated between 32,160 ± 1000 years BP and 17,000 ± 400 BP. These claims have become an issue of contention between North American archaeologists and their South American and European counterparts, who disagree on whether it is conclusively proven to be an older human site.
In 2004, worked stone tools were found at Topper in South Carolina that have been dated by radiocarbon techniques possibly to 50,000 years ago."New Evidence Puts Man In North America 50,000 Years Ago" , ScienceDaily website But, there is significant scholarly dispute regarding these dates. Scholars agree that evidence of humans at the Topper Site date back to 22,900 cal yr BP.Madsen 153
A more substantiated claim is that of Paisley Caves in Oregon, where rigorous carbon-14 and genetic testing appear to indicate that humans related to modern Native Americans were present in the caves over 1000 14C years before the earliest evidence of Clovis. Traces and tools made by another people, the Western Stemmed Tradition, were documented.
A study published in Science presents strong evidence that humans occupied sites in Monte Verde in Chile, at the southern tip of South America, as early as 13,000 years ago.Science, 9 May 2008, "Ancient Algae Suggest Sea Route for First Americans" If this is true, then humans may have entered North America long before the Clovis culture, perhaps as long as 16,000 years ago.
The Tlapacoya site in Mexico is on the base of a remnant volcanic hill on the shore of the former Lake Chalco. Seventeen excavations along the base of Tlapacoya Hill between 1956 and 1973 uncovered piles of disarticulated bones of bear and deer that appeared to have been butchered, plus 2,500 flakes and blades presumably from the butchering activities, plus one unfluted spear point. All were found in the same stratum containing three circular hearths filled with charcoal and ash. Bones of many other animal species were also present, including horses and migratory waterfowl. Two uncalibrated radiocarbon dates on carbon from the hearths came in around 24,000 and 22,000 years ago.José Luis Lorenzo and Lorena Mirambell (coordinadores). "Tlapacoya: 35,000 años de historia del Lago de Chalco," Colección Científica núm 155, serie prehistória, Instituto Nacional de Antropología, México, 1986 At another location, a prismatic microblade of obsidian was found in association with a tree trunk radiocarbon dated (uncalibrated) at roughly 24,000 years ago. This obsidian blade has recently been hydration dated by Joaquín García-Bárcena to 22,000 years ago. The hydration results were published in a seminal article that deals with the evidence for pre-Clovis habitation of Mexico.Joaquín García-Bárcena. "Primeros pobladores: La Etapa Lítica en México," Arqueología Mexicana, Vol. IX, núm. 52, pp. 28–29, 2001.
Other sites, like White Sands National Park in New Mexico, also demonstrate archaeological findings that predate Clovis populations. In White Sands, excavated surfaces uncovered multiple in situ human footprints that were stratigraphically located between layers of material that were radio carbon dated to be from between 21,000 and 23,000 years ago. The findings from this site predate previous theories about the timeline of human migration of the Americas by several thousand years. Archaeologist working on the site believe that their findings indicates that humans had been present in the region since 23,000 years prior. This would mean that humans were occupying North America during the Last Glacial Maximum (LGM) – a theory that had previously been dismissed.
Though it is not currently the widely accepted theory, these archaeological sites support alternative theories of early human migration such as a coastal migration route or the Solutrean hypothesis. This archaeological evidence is also supported by genetic mapping of ancestral mitochondrial DNA.
Archaeological sites that predate Clovis that are well documented include: White Sands National Park, New Mexico, USA; (21,000–23,000 BP)Ancient Footprints Suggest Humans Lived In The Americas Earlier Than Once Thought; by SCOTT NEUMAN; September 24, 2021, at https://www.npr.org/2021/09/24/1040381802/ancient-footprints-new-mexico-white-sands-humans Topper, South Carolina, US (16,000–20,000 yr BP; possibly 50,000 yr BP) Saltville (archaeological site), Virginia, US (14,510 14C yr BP)Madsen 152 Manis Mastodon site, Sequim, Washington, US (13,800 yr BP) Connley Caves, Oregon, US (13,000 yr BP) Lapa do Boquete, Brazil (12,070 ±170 14C yr BP) Tanana Valley, Alaska, US (13,000–14,000 cal yr BP) El Abra, Colombia (12,460 ±140 14C yr BP) Nenana Valley, Alaska, US (12,000 yr BP) Tibitó, Colombia (11,740 ±110 14C yr BP) Tagua-Tagua, Chile (11,380 ±380 14C yr BP)
Coastal migration route
Studies of the mitochondrial DNA of First Nations/Native Americans published in 2007 suggest that the people of the New World may have diverged genetically from Siberians as early as 20,000 years ago, far earlier than the standard theory suggests. According to one alternative theory, the Pacific coast of North America may have been free of ice, allowing the first peoples in North America to come down this route prior to the formation of the ice-free corridor in the continental interior.Meltzer, David J. First Peoples in a New World, Berkeley: University of California Press, 2009, p. 129 No evidence has yet been found to support this hypothesis except that genetic analysis of coastal marine life indicates diverse fauna persisting in refugia throughout the Pleistocene ice ages along the coasts of Alaska and British Columbia; these refugia include common food sources of coastal aboriginal peoples, suggesting that a migration along the coastline was feasible at the time. Some early sites on the coast, for example Namu, British Columbia, exhibit maritime focus on foods from an early point with substantial cultural continuity.Carlson, Roy L. and Luke Dalla Bona, ed.s Early Human Occupation in British Columbia. Vancouver. UBC Press. 1996.
This lack of evidence is likely due to the change in sea level since the time of migration. During the Last Glacial Maximum the global sea level was more than 400 feet lower than it is today. Starting about 15,000 years ago, glaciers began retreating and sea levels began rising. Sea levels reached their current level about 8,000 years ago and have fluctuated slightly since then. This drastic change in sea level may prevent the discovery of sites located along what was once the coastline and is now located under over 400 feet of water. As of now, genetic analysis is one of the only means of tracking early human movements.
In February 2014, researchers reported on their DNA analysis of the remains of Anzick boy (referred to as Anzick-1) of Montana, the oldest skeleton found in the Americas and dated to 12,600 years ago. They found the mtDNA to be D4h3a, "one of the rare lineages associated with Native Americans." This was the same as the mtDNA associated with current coastal populations in North and South America. The study team suggest that finding this genetic evidence so far inland shows that "current distribution of genetic markers are not necessarily indicative of the movement or distribution of peoples in the past." The Y haplotype was found to be Q-L54*(xM3). Further testing found that Anzick-1 was most closely related to Native American populations (see below).
Solutrean hypothesis