America's First Immigrants

TIMES SCIENCE WRITER

From the evidence of words they spoke, the trash they scattered and the genes they left their descendants, the mysterious first settlers of the Americas landed in the New World as long as 40,000 years ago, well before the last ice age swept across the continent, new research suggests.

Based on new findings in linguistics, molecular anthropology and archeology, at least four leading scholars have concluded that these ancient pioneers spread across the Americas eons before the Clovis people, who until recently were believed to have settled the continent about 11,500 years ago.

Moreover, once they made their way to the New World, the earliest American immigrants may have then been isolated from their original Siberian homeland by glacial ice for thousands of years, according to the new research. The spreading glaciers may have forced them to flee far to the south and, as the climate warmed again, they resettled North America.

Until recently, there were no identifiable remains of these enigmatic first-comers to hint at their existence. Indeed, there are only seven known complete skeletons of any ancient North Americans and fragments of about 20 more.

But it appears from human bones recently discovered in Washington state and Nevada that these earliest settlers may not have resembled any contemporary Native Americans or any other living branch of the family of man.

"Preliminary observations of these skeletons suggest that these folks are probably from a population that predated modern North American Indians physically," said Dennis Stanford, chairman of the anthropology department at the Smithsonian Institution. "They appear to be racially different.

"The peopling of the New World," he said, "is a much more complex issue than we had thought heretofore."

While no one is certain yet about the identity of those who first settled the New World, there is a growing scholarly consensus about when they arrived:

* New analysis of Native American languages suggests that people arrived in the New World 30,000 to 40,000 years ago, said Johanna Nichols, a linguistics expert at UC Berkeley. Her research indicates that indigenous languages in the Americas are so diverse--with about 150 distinct language families identified so far--that they must have taken at least that many millenniums to evolve.

Additional analysis also reveals a second, more recent set of language types along the Pacific Coast from Alaska to southern Chile. That means a second wave of migration occurred after the melting of the glaciers reopened access to the Americas about 14,000 years ago.

* Newly discovered clues contained in maternal genes found among the indigenous peoples of the Pacific Rim strongly suggest that the first Americans may have migrated from Siberia--presumably via a land or ice bridge--20,000 to 40,000 years ago, Emory University scientists said. By examining genetic differences in aboriginal groups on both sides of the Bering Strait, the researchers reinforced the idea that early settlers were isolated from Asia for a considerable time--perhaps by a glacial icecap. "These results clearly reveal the significant impact that the glaciers had in shaping the cultural, linguistic and genetic diversity of northern populations and the first Americans," Emory molecular biologist Theodore G. Schurr said.

* New evidence of ancient appetites, in the form of mammoth bones apparently butchered for food at sites in Wisconsin, Nebraska and Virginia, reveals signs of human activity between 13,500 and 18,000 years ago, according to Robson Bonnichsen at Oregon State University. Anthropologist Tom Dillehay at the University of Kentucky said there may be more than 15 sites in South America that could be dated to between 15,000 and 20,000 years ago--all older than the sites inhabited by the Clovis people.

The new findings come as archeologists and anthropologists have finally resolved lingering skepticism over the age of what is now believed to be the oldest known settlement in the New World.

After years of debate, scholars now agree that a prehistoric site called Monte Verde in southern Chile was inhabited at least 12,500 years ago, predating the earliest known Clovis site in New Mexico by about 1,000 years.

Based on her analysis of how quickly languages spread, Nichols suggested that "at a good clip" it might have taken the Monte Verde people about 7,000 years to travel the 8,000 miles from their arrival in Alaska to the tip of South America.

"That points to an entry [into the Americas] of approximately 19,500 years ago, at a minimum," Nichols said.

From geological evidence, however, scientists know that the last ice age peaked 14,000 to 22,000 years ago, which would have blocked any crossing between the Asian and American mainlands at that time.

"So, this speaks to a much earlier entry," she said.

*

Although that makes Monte Verde old enough to shatter scholarly preconceptions, researchers at the site now are analyzing what may be traces of even earlier human occupation there, dating from 33,000 years ago. Dillehay, who has overseen the Monte Verde site and championed its antiquity, said it is possibly so ancient that it even gives even him pause.

"Intellectually--not empirically or scientifically speaking--I still find it somewhat difficult to jump from approximately 12,500 years ago at the site . . . to 33,000 years ago," he said.

Elsewhere, recent archeological evidence reinforces the idea of early human presence in the Americas, said Bonnichsen, who directs the OSU Center for the Study of the First Americans. The evidence includes:

* Stone tools found in association with remains of woolly mammoths at the Chesrow complex in Wisconsin dating to between 12,000 and 13,000 years ago.

* A set of fingerprints preserved in clay at Pendejo Cave in New Mexico that dating shows to be at least 13,000 years old.

* Distinctive lanceolate or "atalatl" spear points found at Cactus Hills in Virginia, dating back 15,000 to 16,000 years ago.

* Stone tools in northern Peru that date from 11,650 years ago. Those tools are similar to those found elsewhere in the Andes and parts of Brazil.

In an effort to identify the people who left these traces, researchers now are turning to the clues contained in the human hair found at many archeological sites.

The hair contains enough carbon, Bonnichsen said, to make it suitable for radiocarbon dating and enough genetic material to shed considerable light on its biology. That would give researchers a way to identify, date and then track different population groups in the absence of any other human remains.

"The DNA evidence from hair may be the key we've been missing in our attempts to link the biological evidence to the archeological evidence," Bonnichsen said.

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Looking fo the First Americans

People first arrived in the New World between 30,000 and 40,000 years ago, say scientists who study Native American languages and genes.

To avoid Ice Age glaciers, these people may have moved far to the south, only to resettle North America thousands of years later when the ice retreated, a UC Berkeley language study says.

Berkeley researchers also found unusual language types along the Pacific Coast that suggest a second wave of migration about 14,000 years ago after glaciers receded.

Scientists at Emory University say their genetic research also shows tht the first Americans migrated from Siberia between 20,000 and 40,000 years ago and were then isolated from Asia for a considerable time--perhaps by a glacial ice cap.

Some Archeologically Significanrt Sites in the New World

1. Bluefish Caves, Alaska

2. Richey-Roberts Clovis cache, Washington state

3. Blackwater Draw, New Mexico

4. Meadowcroft Rockshelter, Pennsylvania

5. Taima-Taima, Venezuela

6. Pedra Furada, Brazil

7. Monte Verde, Chile

Combing Ancient Hair for Clues

To identify the first Americans, researchers are analyzing the human hair found at many archeological sites.

The hair could allow researchers to identify, dae and then track different population groups in the absence of any other human remains.

Sources: UC Berkely, Emory University, American Museum of Natural History

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