The Peopling of the Americas: Year In Review 1998

New sites and new data from old sites are changing the understanding of the peopling of the Americas. For decades the consensus was that the first Americans were big-game hunters who traveled from Asia across the Bering Land Bridge near the end of the Ice Age, about 12,000 years ago. Named for an occupation site in Clovis, N.M., these earliest people, called Paleoindians, are known for their fluted spear points. The Clovis people were thought to have settled in the interior plains of North America between 11,500 and 11,000 years ago. From there, they colonized the Western Hemisphere, following the diminishing game through the upland plains of Central America and the Andes, avoiding the coasts and tropical forests and reaching the tip of South America by 10,000 years ago, the end of the glacial period.

The Clovis migration theory developed early in the history of radiocarbon dating, before much was known of regions outside the Clovis heartland. Abundant new data from several of those areas now cast doubt on the theory. According to these findings, Clovis was not settled early enough to be the ancestor of Central and South American Paleoindians. Several well-documented sites south of the U.S. border are as early as or earlier than Clovis. In addition, few Ice Age cultures on either side of the land bridge had fluted points or hunted big game.

In the interior and coasts of northeast Asia, known late glacial cultures do not include any big-game hunting groups with fluted points. For example, the people of Diuktai in interior Siberia had stemmed, often triangular points and lived by generalized foraging. People near lakes used stemmed projectile points and foraged for small game, fish, and edible plants. In Japan, then connected to the mainland, people also had stemmed points, and fished, gathered nuts and roots, and hunted smaller game for their sustenance.

Located just across the Bering Strait in Alaska, the Nenana culture is considered the most likely ancestor of the Paleoindians. Its age, verified by 20 consistent radiocarbon dates from four sites, spans the years from about 11,800 to 10,700 years ago. With its triangular, nonfluted points and generalized collecting and hunting, the culture is similar to some in contemporary Asia. Site refuse from the earlier part of the occupation contains plant remains and abundant bones of bison, other large and small mammals, birds, fish, and snails. The only mammoth bones, however, were fossils scavenged from paleontological sites for tools. The environment appears to have been a woodlands dominated by birch and willow.

In the high plains the revised Paleoindian sequence now extends from about 11,100 to 8,500 years ago. It still begins with the Clovis culture, whose fluted points are found at mammoth and bison kill sites. Contrary to prior understanding, however, none of the seven definitively dated Clovis occupations is earlier than about 11,200 years ago. After about 10,900 years ago, there is a transition to the Folsom people, who hunted bison with small, finely flaked points with long flutes.

Evidence of early migration had been missing from the Pacific coast, which was flooded after the Ice Age, but Daisy Cave on a hilly channel island near Santa Barbara, Calif., is the site of a newly dated occupation started before 10,500 years ago. The shellfish and carbonized plants that were dated indicate an adaptation to pine-clad coasts that were wetter and cooler than the area is today.

In Eastern North America, several fluted point sites have single dates as early as 11,000 but the Paleoindian sequence has not yet been filled out. (The few pre-Clovis dates are from levels without secure cultural association.) Southeastern points are often termed "Clovis," but their manufacture and shapes resemble those of Folsom, and in some areas the custom of fluting lasts into postglacial times. Eastern sites are often damaged by plowing or erosion, but some have yielded food remains such as fishbone, indicating broader subsistence than specialized big-game hunting.

Central America lacks unequivocal evidence for Paleoindians. There are no well-dated, published Central American sites that appear to have been stopping places on the Clovis migration. The few fluted points are undated surface finds and resemble the postglacial points of southeastern North America. Despite the lack of early human sites, however, charcoal in Panamanian pollen cores suggests that humans passed through the area’s upland rain forests about 11,000 years ago.

In South America many late Pleistocene complexes have been discovered. Contrary to the Clovis theory, the oldest are as early as or earlier than Clovis and are distinct culturally. Triangular and/or stemmed points as in the Asian tradition were found at most of the sites. The food remains indicate collecting and small-game hunting in diverse habitats ranging from the desert coast of the Pacific and the Atlantic tropical rain forests to the pampas and the icy shores of Patagonia.

At Taima Taima, an oil field site in northern Venezuela, fragmentary tools were found with cut mastodon bones in a spring where cultural and natural materials had become mixed. One tool is a bipointed style point. The ancient habitat was swampy, wooded, and subtropical. The radiocarbon dates range too widely for comfort--from about 41,000 to 12,000 B.P. Late Pleistocene people may have killed mastodon there, but exactly when is not certain. In nearby Colombia the earliest securely dated sites are lowland camps from 10,400 to 8,000 years old. Some of these sites contain triangular points, while others have ground-stone tools. Food remains are tropical forest fruits and nuts. The only highland sites are disturbed and of uncertain age.

In the Andes highlands of Peru, early work had uncovered possible big-game kill sites dating to as early as 20,000 years ago, but these had no clear association with humans. Sites with triangular and sometimes stemmed points and diverse modern fauna and flora date to between about 11,500 and 8,500 before the present. The first secure evidence of early Paleoindians on the Pacific coast was from two south Peruvian sites with beginning dates between 11,100 and 10,700 years ago. At Quebrada Tacajuay and Quebrada Jaguay, the ancient hearths contained carbonized fragments of stone tools and remains of shell fish, small fish, and birds, but no large game.

For more than 100 years, researchers have claimed that there were very early human sites in the tropical forests of eastern South America. By the end of 1998, 10 sites had produced beginning dates of 11,000 years ago or slightly earlier. A few produced dates as early as 50,000 years ago, and one was claimed to be hundreds of thousands of years old. Though the earliest dates lacked secure cultural context, extensive cross-dating of plant remains and human skeletons (by radiocarbon) and stone tools and sediments (by thermoluminescence and optically stimulated luminescence) at several sites confirmed initial dates of at least 11,000 years ago. Unlike Clovis sites, those in Brazil include painted caves and rock shelters. Food remains include nuts, legumes, fish, shellfish, and small game animals. Among the artifacts are triangular, sometimes stemmed points but no fluted points. The newly dated sites include Caverna da Pedra Pintada, Santana de Riacho, and Boquete in Brazil. Contrary to some climate theories, east Brazilian forests were denser than today, according to the patterns of ancient species and their carbon isotope ratios.

Monte Verde, Chile is a boggy stream bed in which mastodon bones and wet preserved plant remains were found with a few stone tools, including three bipointed points and a crude biface. Earlier regarded as a questionable site, some researchers have changed their minds. Judged by the standards applied to other sites, however, Monte Verde remains questionable. Dates were run on possibly worked wood and bone, but these are equivocal, since fossil bone and wood occur naturally in the region’s waterways. The only obvious cultural remains were the four tools, most of which were from the surface, and a few non-local plant food remains, which were not dated. The dates at the site range from 14,000 to 12,000--too wide a span for a single occupation. Since postglacial people lived nearby, the points and food remains could be intrusions. Only further work will clarify the situation.

Two roughly contemporary early Paleoindian cultures have been identified in far southern South America. The Fell culture had long been known from Patagonian caves and rock shelters. Fishtail points are distinctive Fell artifacts that once were equated with Clovis points but now are known to have been made and shaped differently. Although extinct horse and sloth remains were found at a few sites, most animals hunted were smaller game, such as guanaco and local birds. The existing 12 radiocarbon dates range between about 11,000 and 10,000 years ago. Farther north and west was the Los Toldos culture, whose sites contain rock paintings; stemmed, triangular points; and evidence of foraging for many kinds of food.

All the new evidence, therefore, has revealed that the first Americans had settled in many different regions by 11,000 years ago. Not only the plains but also the coasts and tropical forests were occupied by the earliest-known people. Thus, Clovis was just one regional specialization among many. Although the new data suggest a different scenario for colonization of the hemisphere, the much earlier dates remain problematic. An initial entry at about 12,000 years ago remains the most viable conclusion.