Friday, October 08, 2004

North American Mythology Migration Articles

North American Mythology Migration Articles

by Sasha Nemecek

... I let my mind wander to imagine life some 14,700 yearsago in the marshes of southern Chile,where this relic was found. The 30 or so people who lived there then, at the creekside campsite now known as Monte Verde, were some of the earliest inhabitants of South America--most likely descendants of people who reached North America by crossing the Bering land bridge from Asia at least 15,000 years ago, perhaps more. Did this roving crew realize they were such pioneers? Or are such musings reserved for people who don't have to worry about where to find their next meal?

My thoughts are interrupted by Tom Dillehay, professor of anthropology at the University of Kentucky and the man who in the 1970s uncovered Monte Verde, the oldest known site of human habitation in the Americas. In a basement classroom on the university's campus, Dillehay has spread out a gallery of artifacts from Monte Verde on the table before me. He directs my attention to a fragment of another spearpoint, which, were it still intact, would be virtually identical to the one I'm holding. "These were probably made by the same person," he says. The misty images of primitive explorers evaporate, and I suddenly picture a single artisan spending hours, perhaps days, crafting these stone tools, each less than four inches long and half an inch wide. The workmanship is exquisite, even to my untrained eye: the series of tiny notches that form the sharp edges are flawlessly symmetrical. Whoever made these tools was clearly a perfectionist.

The question of when people first reached the Americas has been an ongoing discussion in anthropology and archaeology circles for years. Yet how the first Americans actually lived--how my diligent toolmaker spent his (or her?) days--is only now receiving significant attention. The findings at Monte Verde shattered the previously accepted entry date into the Americas, which had been considered to be around 14,000 years ago. (Because of the significance of this shift in thinking, acceptance of the Monte Verde site was a slow process; the archaeological community did not endorse Dillehay's analysis until 1997, when a paper on the site was published in the journal Science.

A handful of scholars still have reservations about the age of the site.)

Excavations under way in the eastern U.S. and throughout South America hint that humans' arrival date may have to be pushed back to as far as 20,000 or even 40,000 years ago. Such discoveries may very well do more than just alter our understanding of how long people have lived in the Americas.

With every new artifact, researchers like Dillehay are slowly piecing together more about the day-to-day lives of the early Americans: how they hunted, what plants they ate, how they moved across vast stretches of land—in short, what life was, really like for those men, women and children who originally settled in the New World.

The canonical view of how humans first reached the Americas can be traced back to 1589, when José de Acosta, a Jesuit missionary to South America, suggested that the original Americans had somehow migrated from Siberia many thousands of years ago. The theory persisted, and by the early part of the 20th century archaeologists had agreed on the identity of the very first Americans. The evidence seemed irrefutable. Archaeological sites dating to approximately 13,000 years ago had turned up all across the landscape; nothing older had yet been found. Moreover, the tools from these sites shared striking similarities, as though the people who created them had a common cultural background and had all moved onto the continent together. Researchers termed these people and their culture "Clovis" (after Clovis, N.M., where the first such artifact was found). Clovis spearpoints, for instance, can be found in Canada, across the U.S. and into Central America.

In certain parts of the U.S., particularly the desert Southwest, these Clovis points are nearly as common as cacti. Why would the Clovis people have needed so many weapons? Again, the answer seemed clear. They must have been voracious hunters, following their prey—big game animals like the woolly mammoth--across the Bering land bridge around 14,000 or 15,000 years ago, when the ice sheets extending from the North Pole had melted just enough to open a land passageway through Canada. The hunters pursued the animals relentlessly, taking around 1,000 years to spread through North and South America. The emphasis on hunting made sense--this was the Ice Age, after all, and meat from a mammoth or bison provided lots of much needed fat and protein for the entire family. And the fur hides could be fashioned into warm clothes.

Thomas Lynch, an expert on Clovis culture and director of the Brazos Valley Museum of Natural History in Bryan, Tex., points out another advantage: "The easiest way to get food is by hunting big game, in particular herding animals. And at first, the animals would not be afraid of humans." A quick sweep across the continent fits the pattern as well, Lynch argues, remarking that the hunters would have had to move fast "as the animals got spooked by humans."

The idea that the first Americans were Ice Age hunters has been accepted for decades, filling pages in both textbooks and scientific journals. But researchers have increasingly pointed to holes in the theory.

David Meltzer, a professor of anthropology at Southern Methodist University who has studied Clovis culture extensively, suggests that this view of the first settlers is too simplistic, relying as it does on a stereotype that "people worked their way through the continent gnawing on mammoth bones." With closer scrutiny, he says, "this just doesn't hold up."

Meltzer contends that the small bands of 15 to 30 people, typical of nomadic tribes, were essentially always at risk of dying out, either from inbreeding or some sort of catastrophe. Hunting a mammoth was, of course, extremely dangerous, possibly even too perilous for these groups to have relied on it as their sole source of food. So they must have turned to other sources, particularly small game, nuts and berries, and maybe even fish and turtles. Indeed, a few archaeologists have discovered the remains of smaller animals, including deer, rabbits and snakes, at Clovis sites. Unfortunately, though, the technology associated with small-game hunting, fishing and gathering--the wooden tools, nets and baskets--generally don't survive as well as stone artifacts do.

One site in Pennsylvania, however, has yielded just these kinds of remains. James Adovasio, an archaeologist at Mercyhurst College, has spent almost 30 years excavating Meadowcroft Rockshelter southwest of Pittsburgh, where early settlers set up camp at least 12,900 years ago. He has found baskets that he believes would have been used to carry plants or even mussels from the nearby Ohio River. Adovasio has also uncovered parts of snares for catching small game, and bone awls for working textiles and hides.

For much of the past three decades, other archaeologists have disputed Adovasio's interpretation of these finds; even today some question the antiquity of the site, although a recent analysis of the site by an outside researcher may help resolve the issue. "We have found bone needles, and people would say, ‘Oh, they used them to sew hides.' But you and I know they would snap!" Adovasio insists. Instead, he argues, these needles must have been for weaving lightweight fabrics made from plant material. "People make the mistake of thinking the Ice Age was cold all the time. They remember the 40,000 Januarys but forget the 40,000 Julys," he laughs.

And just who was sewing clothes for the warmer weather?
Adovasio complains that the official mammoth-centric picture of early Americans completely neglects the role of women, children and grandparents. He points to the icon of the Ice Age hunter with his stone spears: "By focusing only on stones, we are ignoring 95 percent of what these people made and what they did." Look at more recent hunter-gatherer societies, he says. Women, children and older people of both sexes supply the vast majority of the food and carry out vital tasks such as making clothes, nets and baskets. Why would the earliest Americans have been any different? Margaret Jodry, an archaeologist at the Smithsonian Institution, also cautions against overlooking then issue of how families traveled through the New World. Conventional wisdom has the Clovis people walking the entire way. But, Jodry asks, what about Clovis sites that have been found on both sides of a river? "Unless we're suggesting they would swim across" the river every day just to get home, she says incredulously, they must have relied on boats for transportation. "How are you going to swim the Missouri River with Grandma, your wife who's eight months pregnant, your kids and dogs?"

Furthermore, she points out, humans had developed watercraft by at least 40,000 years ago, because by then they were in Australia.

Early American boats would have been constructed from animal skins or wood—again, fairly ephemeral substances. But Jodry thinks that archaeologists might be able to find distinct signatures of the boatbuilding process. Based on her observations of construction techniques used by modern indigenous groups of North America, she has proposed archaeological markers--a certain configuration of post holes encircled by stones, for instance--that might represent an ancient workshop for assembling boats.

In response to these novel lines of reasoning, archaeologists are beginning to change how and where they dig. Jodry reports that some colleagues have told her they plan to revisit previously excavated sites, looking for evidence of boats. And finds at Meadowcroft and elsewhere have prompted archaeologists to hunt for more than just stones and bones. (At Monte Verde, Dillehay found knotted cords that he thinks were used to secure tents made of animal hides; remains of the tents turned up as well.)

But they'll have to change the types of sites they look for, according to Dillehay. "People concentrate on caves and open-air sites," he explains, where preservation of delicate artifacts is unlikely. "If you want to find another Monte Verde"--where a layer of peat from the nearby swamp covered the campsite and prevented oxygen from reaching the remains--"you've got to look where wet sites are preserved," he says.

This newfound emphasis on softer artifacts should help to substantiate the emerging picture of the first Americans as people with an intricate knowledge of their environment, who could not only spear a mammoth once in a while but who also knew how to catch fish, pick the right berries, weave plant fibers into clothes and baskets, and build boats for local travel.

And as researchers cast a wider net for artifacts, they may have to consider a range of explanations for what they find. Texas A&M University archaeologist and Clovis specialist Mike Waters notes that when the archaeological community accepted the 14,700-year-old date for Monte Verde just three years ago, the recognition "jump-started the whole debate about Clovis being first." As scholars digest the evidence from Monte Verde, they have been rethinking many long-held ideas on who populated the Americas and when and how they got here [see map]. For his part, Waters maintains three working hypotheses: that the Clovis people were in fact the first in the Americas, that there was a smattering of people in North America before Clovis but they left almost no trace or that there was a large pre-Clovis occupation we have yet to identify.

Transportation to the New World is a big topic for debate. If the early Americans did cruise around the continent in canoes and kayaks, might the first settlers have arrived by boat as well? For decades the archaeological community rejected this notion (Ice Age hunters could never have carried all their weapons and leftover mammoth meat in such tiny boats!), but in recent years the idea has gathered more support. One reason for the shift: the nagging problem of just how fast people can make the journey from Alaska to Tierra del Fuego.

Consider Dillehay's 14,700-year-old Monte Verde site.
According to the previously accepted timeline, people could have made the journey from Asia on foot no earlier than 15,700 years ago (before this time, the ice sheets extending from the North Pole covered Alaska and Canada completely, making a land passage impossible). If this entry date is correct, the Monte Verde find would indicate that the first settlers had to make the 12,000-mile trip through two continents in only 1,000 years. In archaeological time, that's as fast as Marion Jones.

One way to achieve this pace, however, would be by traveling along the Pacific coastlines of North and South America in boats. Knut Fladmark, a professor of archaeology at Simon Fraser University in Burnaby, B.C., first suggested this possibility in the 1970s and remains an advocate of a coastal entry into the Americas. If people had a reason to keep moving, he says, they could have traversed both continents in 100 years. Fladmark estimates that traveling at a rate of 200 miles a month would have been quite reasonable; the settlers no doubt stopped during winter months and probably stayed in some spots for a generation or so if the local resources were particularly tempting.

Fladmark's theory, though enticing, won't be easy to prove. Rising sea levels from the melting Ice Age glaciers inundated thousands of square miles along the Pacific coasts of both continents. Any early sites near the ocean that were inhabited before 13,000 years ago would now be deep underwater.

Recently a few enterprising researchers have attempted to dredge up artifacts from below the Pacific.
In 1997, for example, Daryl Fedje, an archaeologist with Parks Canada (which runs that country's national parks system), led a team that pulled up a small stone tool from 160 feet underwater just off the coast of British Columbia. The single tool, which Fedje estimates to be around 10,200 years old, does establish that people once lived on the now submerged land but reveals little about the culture there.

Excavating underwater sites might turn out to be the only way to prove when humans first arrived on this continent. And for many researchers this is still a very open question, with answers ranging from 15,000 years ago to as far back as 50,000 years ago.
When Fladmark first proposed the idea of a coastal migration, the entry date of 14,000 or 15,000 years ago was orthodoxy. But many researchers have since speculated that humans must have been in the Americas for much, much longer.

Which brings me back to my skilled spearpoint designer from Monte Verde. Although his ancestors theoretically could have made it to the southern tip of Chile in just 100 years if the traveled in watercraft, practically speaking, the group wouldn't then have had much time to adaptt to the new surroundings.

And for Dillehay, this distinction between theory and reality is crucial: The people living at Monte Verde 14,700 years ago, he says, "knew exactly where they were positioning themselves." They had been in the region long enough to set up camp on prime real estate, within an hour's walk of nearby wetlands, lush with edible plants. The ocean and the Andean foothills were both about a day's walk away. The group had carefully situated itself close to three different environments, all of which provided them with food and supplies.

Dillehay has found desiccated cakes, or "quids," of seaweed that the people sucked on, probably for the high iodine content in the plants (the quids are almost perfect molds of the top of a person's mouth down to the impressions of molars). And based on the mastodon bones found at the site, Dillehay believes that the Monte Verdeans either killed or scavenged animals trapped in the nearby bogs. He also suspects they used rib bones from the animals as digging sticks to unearth tubers and rhizomes from the surrounding marshes.

Such elaborate knowledge of one's environment does not come quickly; it probably requires several generations at least. Precisely how long the folks at Monte Verde would have needed to gain such an understanding, though, is difficult to estimate. The arrival of modern humans into an unpopulated continent has happened only twice--in Australia and in the Americas--so we have little by way of reference. But Dillehay looks at the issue in a broader context. In places like the Indus Valley and China, it took tens of thousands of years for complex civilizations to arise. He remarks that unless Americans were "the most remarkable people in the world setting up the beginnings of civilization in only a couple thousand years—they must have been here for much longer. Dillehay suggests that an arrival time of around 20,000 years ago would have given the first Americans ample time to put down the roots of civilization.

Such an early entry date is bolstered by two other lines of evidence. Linguist Johanna Nichols of the University of California at Berkeley argues that the amazing diversity of languages among Native Americans could have arisen only after humans had been in the New World for at least 20,000 years--possibly even 30,000.

Geneticists, including Theodore Schurr of the Southwest Foundation for Biomedical Research in San Antonio, Tex., and Douglas Wallace of Emory University, present a related argument based on genetic diversity. By comparing several DNA markers found in modern Native Americans and modern Siberians, Schurr and Wallace estimate that the ancestors of the former left Siberia for the New World at least 30,000 years ago.

These ancient dates--if they are correct--would have important implications. Experts on human origins believe that behaviorally modern humans left Africa for Europe and Asia around 50,000 or 60,000 years ago. So as archaeologists push back the arrival date of humans in the Americas, they move the peopling of the New World into the larger story of human evolution. As Robson Bonnichsen, director of the Center for the Study of the First Americans at Oregon State University, has written, the occupation of the Americas should be "understood in respect to the process that led to the global expansion of modern humans."

Some evidence links the settling of the Americas to the migration of modern humans out of Africa. In perhaps one of the most startling finds of recent years, Walter Neves of the University of São Paulo determined that the oldest skeleton ever found in the Americas--a 13,500-year-old adult female from southeastern Brazil--resembles Africans and Australian aborigines more than modern Asians or Native Americans. Neves interprets this result (and similar ones from some 50 skulls dated to between 8,900 and 11,600 years old) to mean that non-Mongoloid migrants were among the first in the Americas.

Neves is quick to point out, though, that he does not think these people came directly from Africa or Australia but that they splintered off from the band moving slowly through Asia that eventually went south to Australia. According to the fossil record, Mongoloid groups arrived in South America around 9,000 years ago, where they appear to have replaced the previous population. "I don't have an answer for [what happened]," Neves says. "Maybe war, maybe killing, maybe they were absorbed" by all the intermixing that was surely going on, he suggests.

So it seems the New World has been a melting pot for millennia. Those famous Ice Age hunters no doubt did cross the Bering land bridge at some point and head onto the continent. But they probably were not the first ones to do so, and they most certainly were not the only ones. Thanks to recent archaeological finds, researchers are beginning to figureout what life was like for some of the other people here--the fisherfolk boating along the Pacific coast, the hunter--gatherers living in the temperate forests of North and South America.

In the meantime, investigators can't dig fast enough to keep pace with the rapid shifts in our knowledge of who the first Americans were. Archaeologists are couring Alaska for remains of early inhabitants; geologists are trying to determine exactly when the glaciers melted enough for settlers to start moving into central Canada and the U.S. Others continue hunting for even earlier signs of Clovis in the U.S. The eastern U.S. is home to several important ongoing excavations: Cactus Hill in Virginia and Topper Site in South Carolina. Preliminary finds at Cactus Hill suggest that a group possibly related to the Clovis people may have lived in the area around 18,000 years ago.

Al Goodyear, an archaeologist at the University of South Carolina, went back to a Clovis site at Topper, near the Savannah River, to see what was underneath (and thus older).
The results surprised him: artifacts in the deeper layers at Topper are completely unlike Clovis technology. He has found no Clovis-type spearpoints, only tiny stone blades and scraping tools thought to be associated with the use of wood, bone and antlers Goodyear recounts how he "went into a mild state of shock" when he realized just how difficult it would be to explain who these people were. This summer he brought in two experts on determining the age of archaeological sites, Waters of Texas A&M and Tom Stafford of Stafford Research. The story will continue.


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