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In 1964, the year Haynes announced the Clovis-first model, archaeologist Alex D. Krieger listed fifty sites said to be older than Clovis. By 1988 Haynes and other authorities had shot them all down with such merciless dispatch that victims complained of persecution by the “Clovis police.” Haynes, the dissenters said, was a new Hrdlička (minus the charge of insensitivity to living Native Americans). As before, archaeologists became gun-shy about arguing that Indians arrived in the Americas before the canonical date. Perhaps as a result, the most persuasive scientific critiques on Clovis initially came from fields that overlapped archaeology, but were mainly outside of it: linguistics, molecular biology, and geology.
From today’s vantage, the attack seems to have begun, paradoxically, with the publication in 1986 of a landmark
pro-
Clovis paper in
Current Anthropology
by a linguist, a physical anthropologist, and a geneticist. The linguistic section attracted special attention. Students of languages had long puzzled over the extraordinary variety and fragmentation of Indian languages. California alone was the home of as many as 86 tongues, which linguists have classified into between 5 and 15 families (the schemes disagree with one another). No one family was dominant. Across the Americas, Indians spoke some 1,200 separate languages that have been classified into as many as 180 linguistic families. By contrast, all of Europe has just 4 language families—Indo-European, Finno-Ugric, Basque, and Turkic—with the great majority of Europeans speaking an Indo-European tongue. Linguists had long wondered how Indians could have evolved so many languages in the thirteen thousand years since Clovis when Europeans had ended up with many fewer in the forty thousand years since the arrival of humans there.
In the first part of the 1986 article, Joseph H. Greenberg, a linguist at Stanford, proclaimed that the profusion of idioms was more apparent than real. After four decades of comparing Native American vocabularies and grammars, he had concluded that Indian languages belonged to just three main linguistic families: Aleut, spoken by northern peoples in a broad band from Alaska to Greenland; NaDené, spoken in western Canada and the U.S. Southwest; and Amerind, much the biggest family, spoken everywhere else, including all of Central and South America. “The three linguistic stocks,” Greenberg said, “represent separate migrations.”
According to Greenberg’s linguistic analysis, paleo-Indians had crossed over Beringia not once, but thrice. Using glottochronology he estimated that the ancestors of Aleuts had crossed the strait around 2000
B.C.
and that the ancestors of Na-Dené had made the journey around 7000
B.C.
As for Amerind, Greenberg thought, “we are dealing with a time period probably greater than eleven thousand years.” But it was not
that
much greater, which indicated that the ancestors of Amerind-speaking peoples came over at just about the time that Clovis showed up in the archaeological record. Clovis-first, yes, but Clovis the first of three.
In the same article, Christy G. Turner II, a physical anthropologist at Arizona State, supported the three-migrations scheme with dental evidence. All humans have the same number and type of teeth, but their characteristics—incisor shape, canine size, molar root number, the presence or absence of grooves on tooth faces—differ slightly in ways that are consistent within ethnic groups. In a fantastically painstaking process, Turner measured “28 key crown and root traits” in more than 200,000 Indian teeth. He discovered that Indians formed “three New World dental clusters” corresponding to Greenberg’s Aleut, Na-Dené, and Amerind. By comparing tooth variation in Asian populations, Turner estimated the approximate rate at which the secondary characteristics in teeth evolved. (Because these factors make no difference to dental function, anthropologists assume that any changes reflect random mutation, which biologists in turn assume occurs at a roughly constant rate.) Applying his “worldwide rate of dental microevolution” to the three migrations, Turner came up with roughly similar dates of emigration. Amerinds, he concluded, had split off from northeast Asian groups about fourteen thousand years ago, which fit well “with the widely held view that the first Americans were the Clovis-culture big-game-hunting paleo-Indians.”
The article provoked vigorous reaction, not all of the sort that its authors wished. In hindsight, a hint of what was to come lay in its third section, in which Arizona State geneticist Stephen L. Zegura conceded that the “tripartite division of modern Native Americans is still without strong confirmation” from molecular biology. To the authors’ critics, the lack of confirmation had an obvious cause: the whole three-migrations theory was wrong. “Neither their linguistic classification nor their dental/genetic correlation is supported,” complained Lyle Campbell, of the State University of New York at Buffalo. Greenberg’s three-family division, Campbell thought, “should be shouted down in order not to confuse nonspecialists.” The Amerind-language family was so enormous, Berkeley linguist Johanna Nichols complained, that the likelihood of being able to prove it actually existed was “somewhere between zero and hopeless.”
Although the three-migrations theory was widely attacked, it spurred geneticists to pursue research into Native American origins. The main battleground was mitochondrial DNA, the special DNA with which Pena, the Brazilian geneticist, hoped to find the Botocudo. As I mentioned before, a scientific team led by Douglas Wallace found in 1990 that almost all Indians belong to one of four mitochondrial haplogroups, three of which are common in Asia (mitochondria with similar genetic characteristics, such as a particular mutation or version of a gene, belong to the same haplogroup). Wallace’s discovery initially seemed to confirm the three-migrations model: the haplogroups were seen as the legacy of separate waves of migration, with the most common haplogroup corresponding to the Clovis culture. Wallace came up with further data when he began working with James Neel, the geneticist who studied the Yanomami response to measles.
In earlier work, Neel had combined data from multiple sources to estimate that two related groups of Central American Indians had split off from each other eight thousand to ten thousand years before. Now Neel and Wallace scrutinized the two groups’ mitochondrial DNA. Over time, it should have accumulated mutations, almost all of them tiny alterations in unused DNA that didn’t affect the mitochondria’s functions. By counting the number of mutations that appeared in one group and not the other, Neel and Wallace determined the rate at which the two groups’ mitochondrial DNA had separately changed in the millennia since their separation: .2 to .3 percent every ten thousand years. In 1994 Neel and Wallace sifted through mitochondrial DNA from eighteen widely dispersed Indian groups, looking for mutations that had occurred since their common ancestors left Asia. Using their previously calculated rate of genetic change as a standard, they estimated when the original group had migrated to the Americas: 22,414 to 29,545 years ago. Indians had come to the Americas ten thousand years before Clovis.
Three years later, Sandro L. Bonatto and Francisco M. Bolzano, two geneticists at the Federal University of Rio Grande do Sul, in the southern Brazilian city of Pôrto Alegre, analyzed Indian mitochondrial DNA again—and painted a different picture. Wallace and Neel had focused on the three haplogroups that are also common in Asia. Instead, the Brazilians looked at the fourth main haplogroup—Haplogroup A is its unimaginative name—which is almost completely absent from Siberia but found in every Native American population. Because of its rarity in Siberia, the multiple-migrations theory had the implicit and very awkward corollary that the tiny minority of people with Haplogroup A just happened to be among the small bands that crossed Beringia—not just once, but several times. The two men argued it was more probable that a single migration had left Asia, and that some people in Haplogroup A were in it.
By tallying the accumulated genetic differences in Haplogroup A members, Bonatto and Bolzano calculated that Indians had left Asia thirty-three thousand to forty-three thousand years ago, even earlier than estimated by Wallace and Neel. Not only that, the measurements by Bonatto and Bolzano suggested that soon after the migrants arrived in Beringia they split in two. One half set off for Canada and the United States. Meanwhile, the other half remained in Beringia, which was then comparatively hospitable. The paleo-Indians who went south would not have had a difficult journey, because they arrived a little bit
before
the peak of the last Ice Age—before, that is, the two glacial sheets in Canada merged together. When that ice barrier closed, though, the Indians who stayed in Beringia were stuck there for the duration: almost twenty thousand years. Finally the temperatures rose, and some of them went south, creating a second wave and then, possibly, a third. In other words, just one group of paleo-Indians colonized the Americas, but it did so two or three times.
As other measurements came in, the confusion only increased. Geneticists disagreed about whether the totality of the data implied one or more migrations; whether the ancestral population(s) were small (as some measure of mitochondrial DNA diversity suggested) or large (as others indicated); whether Indians had migrated from Mongolia, the region around Lake Baikal in southern Siberia, or coastal east Asia, even possibly Japan.
Everything seemed up for grabs—or, anyway, almost everything. In the welter of contradictory data, University of Hawaii geneticist Rebecca L. Cann reported in 2001, “only one thing is certain”: scientists may argue about everything else, she said, but they all believe that “the ‘Clovis First’ archaeological model of a late entry of migrants into North America is unsupported by the bulk of new archaeological and genetic evidence.”
COAST TO COAST
The “new archaeological evidence” to which Cann referred was from Monte Verde, a boggy Chilean riverbank excavated by Tom Dillehay of the University of Kentucky; Mario Pino of the University of Chile in Valdivia; and a team of students and specialists. They began work in 1977, finished excavation in 1985, and published their final reports in two massive volumes in 1989 and 1997. In the twenty years between the first shovelsful of dirt and the final errata sheets, the scientists concluded that paleo-Indians had occupied Monte Verde at least 12,800 years ago. Not only that, they turned up suggestive indications of human habitation more than
32,000
years ago. Monte Verde, in southern Chile, is ten thousand miles from the Bering Strait. Archaeologists have tended to believe that paleo-Indians would have needed millennia to walk from the north end of the Americas to the south. If Monte Verde was a minimum of 12,800 years old, Indians must have come to the Americas thousands of years before that. For the most part, archaeologists had lacked the expertise to address the anti-Clovis evidence from genetics and linguistics. But Monte Verde was
archaeology.
Dillehay had dug up something like a village, complete with tent-like structures made from animal hides, lashed together by poles and twisted reeds—a culture that he said had existed centuries before Clovis, and that may have been more sophisticated. Skepticism was forceful, even rancorous; arguments lasted for years, with critics charging that Dillehay’s evidence was too low-quality to accept. “People refused to shake my hand at meetings,” Dillehay told me. “It was like I was killing their children.”
Tom Dillehay
In 1997 a dozen prominent researchers, Haynes among them, flew to Chile to examine the site and its artifacts. The hope was to settle the long-standing dispute by re-creating the graybeards’ visit to Folsom. After inspecting the site itself—a wet, peaty bank strikingly unlike the sere desert home of Folsom and Clovis—the archaeologists ended up at a dimly lighted cantina with the appropriate name of La Caverna. Over a round of beers an argument erupted, prompted, in part, by Haynes’s persistent skepticism. Dillehay told Haynes his experience with stone tools in Arizona was useless in evaluating wooden implements in Peru, and then stomped outside with a supporter. But despite the heated words, a fragile consensus emerged. The experts wrote an article making public their unanimous conclusion. “Monte Verde is real,” Alex W. Barker, now at the Milwaukee Public Museum, told the
New York Times.
“It’s a whole new ball game.”
Not everyone wanted to play. Two years later Stuart J. Fiedel, a consulting archaeologist in Alexandria, Virginia, charged that Dillehay’s just-published final Monte Verde report was so poorly executed—“bungled” and “loathsome” were among the descriptors he provided when we spoke—that verifying the original location “of virtually every ‘compelling,’ unambiguous artifact” on the site was impossible. Stone tools, which many archaeologists regard as the most important artifacts, have no organic carbon and therefore cannot be carbon-dated. Researchers must reckon their ages by ascertaining the age of the ground they are found in, which in turn requires meticulously documenting their provenance. Because Dillehay’s team had failed to identify properly the location of the stone tools in Monte Verde, Fiedel said, their antiquity was up to question; they could have been in a recent sediment layer. Haynes, who had authenticated Monte Verde in 1997, announced in 1999 that the site needed “further testing.”