The Clovis First theory was the most widely accepted idea among scientists in the second half of the 20th century to explain how the first people arrived in the Americas. This theory stated that the Clovis people, known for their unique stone tools, were the first humans to live in the Americas. However, later studies began to question this idea, suggesting that humans may have lived in the Americas before the Clovis culture. In 2011, scientists studied a site called Buttermilk Creek in Texas and found evidence of human activity older than the Clovis culture. At this site, archaeologists discovered tools made by early hunter-gatherer groups, including spear points, blades, and choppers. These tools were made from local chert and could be as old as 15,000 years.

For many years, the Clovis First theory was supported because no clear evidence of earlier human presence had been found. According to this theory, the Clovis people traveled from Siberia to Alaska during the ice age, crossing a land bridge called Beringia, which connected Asia and North America. As glaciers melted, they moved south through an ice-free area in present-day Western Canada.

Research by scientists Michael Waters and Thomas Stafford from Texas A&M University showed that the Clovis people lived in the United States between 13,200 and 12,900 years ago, which is about 450 years later than previously believed. Since the early 2010s, scientists have agreed that humans lived in the Americas before the Clovis culture, which means the Clovis First theory is no longer the main explanation.

Alternatives to Clovis First

Archaeological discoveries across the Americas show evidence of human activity that happened before the arrival of humans around 11,500–11,000 years ago. One such site is the Buttermilk Creek Complex in Salado, Texas, where over 15,000 artifacts, including small stone tools, were found. These tools were buried below older layers of soil that contain Clovis artifacts, meaning they are older than the Clovis culture. These older tools are dated to between 13,200 and 15,500 years ago.

Some groups that came before the Clovis people may have traveled south along the coasts of North America. Evidence from the Monte Verde site in Chile suggests that people similar to the Clovis culture lived there as early as 18,500 to 14,500 years ago. Remains found on the Channel Islands of California show that people lived there 12,500 years ago. These findings suggest that early humans may have moved quickly along the Pacific coastline and later moved eastward into the continent.

The Pedra Furada sites in Brazil include rock shelters used by people for thousands of years. Early excavations found artifacts dated to 48,000 to 32,000 years ago, with some findings extending back to 60,000 years ago. These dates have caused debate among archaeologists in North America, South America, and Europe, who disagree on whether the site proves humans lived there that long ago.

In 2004, stone tools found at the Topper site in South Carolina were dated to possibly 50,000 years ago, but scientists disagree about these dates. However, evidence shows humans were present at the Topper site at least 22,900 years ago.

At the Paisley Caves in Oregon, tests using carbon dating and genetic analysis show that people related to modern Native Americans were there more than 1,000 years before the earliest Clovis evidence. Tools made by a different group, called the Western Stemmed Tradition, were also found there.

A study in Science shows that humans lived in Monte Verde, Chile, as early as 13,000 years ago. If true, this suggests humans may have arrived in North America up to 16,000 years before the Clovis culture.

The Tlapacoya site in Mexico, near the shore of an ancient lake, has evidence of human activity. Excavations found bones of animals like bears and deer that had been butchered, along with stone tools and a spear point. Charcoal and ash from fires were dated to about 24,000 and 22,000 years ago. An obsidian blade found nearby was dated to 22,000 years ago.

At White Sands National Park in New Mexico, human footprints were found in layers of soil dated to between 21,000 and 23,000 years ago. These findings challenge earlier ideas about when humans arrived in the Americas, suggesting they may have been there during the Last Glacial Maximum, a time previously thought to be too cold for human survival.

These discoveries support theories about how humans first reached the Americas, such as traveling along coastal routes or through the Solutrean hypothesis, which suggests Clovis people may have inherited tools from people in Europe. Genetic studies of Native American DNA also support these ideas, showing that people in the Americas may have separated from Siberian populations as early as 20,000 years ago.

Some early sites, like Namu in British Columbia, show evidence that early people focused on coastal food sources, suggesting a coastal migration was possible. However, changes in sea levels since the last ice age may have made it difficult to find older coastal sites, as much of the coastline is now underwater.

In 2014, DNA from the remains of a boy in Montana, called Anzick-1, was analyzed. His DNA matched that of modern Native American populations and coastal groups, showing that people lived far inland as early as 12,600 years ago. This suggests that genetic patterns today may not reflect how people moved in the past.

The Solutrean hypothesis, proposed in 1999, suggests that Clovis people may have inherited tools from the Solutrean people of southern Europe, who lived 21,000–15,000 years ago. This idea is based on similarities between tools found in Europe and those used by Clovis people.

Other sites

Other sites include (in approximate reverse chronological order):

• Pedra Furada, located in the Serra da Capivara National Park in Piauí, Brazil, has evidence of human remains that are not related to the Clovis culture. The site includes rock art drawings, or rupestre art, that are at least 12,000–6,000 years old. Charcoal samples from hearths were carbon-dated to 48–32,000 years ago in a Nature article (Guidon and Delibrias 1986). Later studies using ABOX dating found even older samples, 54,000 years ago, in the Quaternary Science Reviews. Some researchers, including David J. Meltzer, James M. Adovasio, and Tom Dillehay, have questioned the significance of these findings.

• The Monte Verde site in Chile was occupied around 14,800 years ago. Bones and other remains found there are 14,500 years old on average. Earlier findings, dated between 32,840 and 33,900 years ago, are controversial.

• The Bluefish Caves in Yukon, Canada, contain bones with human cut-marks, showing humans were present as early as 24,000 years ago. This site is currently the oldest known archaeological site in North America. It supports the Beringia Standstill hypothesis, which suggests a group of humans remained isolated in the Beringia region during the last ice age before spreading into North and South America after the glaciers melted.

• Lagoa Santa in Minas Gerais, Brazil, is incorrectly claimed to be from the Clovis era or earlier. Recent studies, including those on the Lapa Vermelha IV site and the Luzia skull, clarify that the 11,500 years before present date refers to a chronological scale and not a raw radiocarbon date. Most Clovis sites are dated to 11,500–11,000 radiocarbon years ago, which is 13,000 years before present at a minimum. The Luzia skull is at least 1,000 years younger than Clovis, and Lapa Vermelha IV should not be considered a Pre-Clovis site.

• Cueva del Milodón in Patagonian Chile dates to at least 10,500 years ago. This site was discovered in 1896 and requires more research. If the date is 10,500 radiocarbon years before present, it is 500–700 years younger than Clovis. It should not be considered a Pre-Clovis site.

• Cueva Fell and Pali Aike Crater in Patagonia have hearths, stone tools, and other signs of human activity dating to at least 11,000 years ago.

• The Big Eddy Site in southwestern Missouri contains claimed pre-Clovis artifacts or geofacts. In situ artifacts were found with charcoal, and five samples were AMS dated to 11,300–12,675 years ago.

• Taima Taima in Venezuela has cultural materials similar to Monte Verde II, dating to 12,000 years ago. Artifacts from the El Jobo complex were found with butchered mastodon remains. Radiocarbon dating of wood twigs shows the mastodon kill occurred at least 13,000 years ago, older than Clovis.

• The Page–Ladson site on the Aucilla River in Florida has evidence of mastodon butchering by humans 15,550 years ago. A cut mastodon tusk dated to 12,300 years ago was found near in situ artifacts. A test pit in 1983 revealed elephant bones, bone tools, and tool-making chips. Radiocarbon dating of organic material from the pit ranged from 13,000 to 11,700 years ago.

• The Schaefer and Hebior mammoth sites in Kenosha County, Wisconsin, show human butchering marks on mammoth bones. The Schaefer site has 13 AMS dates on collagen and 17 dates on wood, dating to 12,300–12,500 radiocarbon years ago. The Hebior site has two similar dates.

• A site in Walker, Minnesota, with stone tools claimed to be 13,000–15,000 years old, was discovered in 2006. Further analysis suggests it does not represent human occupation.

• In a 2011 Science article, Waters et al. described 15,528 lithic artifacts from the Debra L. Friedkin site in Texas. These artifacts, including tools and debris, form the Buttermilk Creek Complex, which is stratigraphically below a Clovis assemblage. Optically stimulated luminescence (OSL) dating of sediment layers gave ages between 14,000 and 17,500 years ago. The minimum age of the Buttermilk clays is estimated to be 13,200–15,500 years ago.

• Human coprolites (fossilized feces) in **P