Humans arrived in North America at least 15,500 years ago. How they got there, however, is one of the longest debates in archaeology.
For years, scientists assumed that humans first came to America by walking south from the now-flooded Bering Strait land bridge that once connected Russia and Alaska when sea levels were lower during this ice age. spent But recent evidence suggests that these people were not the first to set foot on the continent.
According to the now dominant “coastal route theory”, that distinction belongs to people who sailed down the Pacific coast several thousand years earlier. 2023 study (opens in a new tab)for example, it was found that coastal conditions were favorable during two time windows: from 24,500 to 22,000 years ago, and from 16,400 to 14,800 years ago. And while the science is far from settled, the evidence points more to the first Americans arriving by sea or land along the coast.
“The pendulum is swinging in favor of the coastal corridor being the route taken by the first Americans,” Michael Waters (opens in a new tab), director of the Center for the Study of First Americans at Texas A&M University, told Live Science in an email. “But we still have to smoke the smoking gun: an early location along the coast.”
Until 20 years ago, the best available archaeological evidence (opens in a new tab) suggests that humans first arrived in North America approximately 13,000 years ago. The rise of the Clovis people – whose 13,400-year-old remains were discovered in Clovis, New Mexico, in the early 1900s – coincided perfectly with the formation of an ice-free corridor along the Rocky Mountains.
Scientists assumed that these people crossed what is now the Bering Land Bridge into Alaska, and then turned south to march on to New Mexico through that convenient passage. This still prevails theory about how the Clovis people made it to America. “It appears that people from northeast Asia came through the ice-free corridor when this route was open and viable,” Todd Braje (opens in a new tab)chair of anthropology at San Diego State University, told Live Science in an email.
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But recent excavations suggest that the Clovis were not the first Americans. 2011 paper in the journal Science (opens in a new tab) presented evidence of human-made tools in Texas up to 15,500 years ago, and a 2021 paper in Science (opens in a new tab) Put down 23,000-year-old footprints in New Mexico. (However, the 2022 study in the journal disputes the lookup date Quaternary Research (opens in a new tab)which confirms that the original team had the seeds of the plant radiocarbon date the tracking layer is problematic.)
These “pre-Clovis people” would have had to migrate to the Americas long before the ice-free corridor opened. “The earliest the inland corridor was opened was 14,300 years ago,” Waters said. “It is impossible that people in Texas and Idaho at 16,000 years ago, and Florida at 14,600 years ago, would have come through the corridor. They must have come in a different way.”
How the pre-Clovis found America without an inland corridor to take them south of the Bering Strait is still an open question. “With the breaking of the Clovis barrier in the 1990s, we know that there were people in America before at least 14,000 years ago, but when people first arrived and in what way or ways are still unknown,” said Braje. “There are now lively debates on the matter but the bottom line is that nobody knows for sure.”
The prevailing theory is that the pre-Clovis people arrived on watercraft. “It is certain that the route taken by the first emigrants was along the coast,” it was said Matthew Des Lauriers (opens in a new tab)director of the Applied Archeology Program at California State University, San Bernardino.
Des Lauriers described the pre-Clovis as sophisticated maritime hunters, who would have left south of the Bering Land Bridge and scavenged for fish and game as they traveled down the Pacific coast. Ultimately, Des Lauriers said, these ruthless killers parted ways. Some pre-Clovis people followed rivers inland, while others continued south as far as Chile.
“The ocean would have always provided resources for skilled fishermen and hunters,” Des Lauriers told Live Science in an email. “The most likely scenario is coastal fisher-hunter-gatherers moving along the North Pacific Coast.”
Recent work by geologists has supported the theory that the Clovis people came via an inland route, while the pre-Clovis people took a coastal route. Beryllium-10 dating of glacial boulders (opens in a new tab) along the ice-free corridor suggests that the corridor was opened about 13,800 years ago. And studies (opens in a new tab) suggests that an unglaciated strip of land along the Pacific coast of Alaska and British Columbia should have existed 16,000 years ago — prime real estate for a coastal corridor.
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As the field of ancient genetics flourished, multiple studies (opens in a new tab) They have provided further evidence that the first Americans arrived between 15,000 and 17,000 years ago.
“It is a source of satisfaction archaeological and genetic evidence is coming together to tell the same story,” Waters said. “Finally, we have a much better understanding of the chronology of the opening of both corridors, and the evidence now supports a coastal migration route.”
However, physical evidence for both pathways is still lacking. Considerable archaeological, genetic and geological legwork will be required before we can firmly pinpoint the lives and times of the first Americans and begin to describe, with confidence, how they came to America.
“There are very few sites along the Pacific Coast that are pre-Clovis in age, and much work needs to be done to identify potential early coastal sites,” Braje said. “We don’t have any definitive answers as to when and how people first came to America.”