Online chapter

Las sociedades originarias
(The Indigenous societies)

Director
Teresa Rojas Rabiela (Mexico)

Codirector
John V. Murra (United States of America)

Chapter 2: The Original Peopling of Latin America
Alan L. Bryan

An old assumption of Americanist archaeologists is the idea that people did not live in the subarctic until after 20,000 B. P. Siberian archaeologists working on the Yenesei, Angara, and Lena Rivers are excavating several sites containing Middle and Lower Palaeolithic artefact in stratigraphic contexts radiocarbon datable to more than 35,000 years (e.g., Drozdov, et al. l990), and several sites are geologically datable to as much as 200,000 years ago (Larichev, et al. l987). One example, the Diring-Yurekh site on the Middle Lena River near Yakutsk in the coldest part of the northern hemisphere, has yielded a pebble core and flake industry in a gravel bed capping an ancient river terrace and underlying a thick sand bed (Ackerman l990; Larichev, et al. l987). The sand has yielded thermoluminescence and paleomagnetic dates that the Russian archaeologist Iuri Mochanov has interpreted as early Pleistocene, although geologists who have visited the site are of the opinion that it probably dates between 200,000 and 300,000 years. No matter how the controversy over dating is resolved, this and other sites indicate that people had adapted to Siberian subarctic and arctic environments long before innovation of specialized Upper Palaeolithic technologies. A site has recently been found on the Chukchi Peninsula near the Bering Land Bridge. The site reportedly has yielded a date of 35,000 B. P., which is within the range of time that sites containing wedge-shaped cores and microblades were used in Mongolia and North China. All of these reports are preliminary and detailed descriptions are awaited; but reports that people with a Middle or Lower Palaeolithic technology were in central Siberia by 200,000 years ago, and already on the western edge of the land bridge as early as 35,000 years ago certainly casts doubt on the assumption of initial occupation only 20,000 years ago.

In north China, it has long been known that Homo erectus with a Lower Palaeolithic technology was present between 250,000 and 500,000 years ago, and recently this time frame has been extended to 1,000,000 years. In Japan, several Middle Palaeolithic sites are being excavated on Honshu. Japanese archaeologists and geologists believe the time frame at some of these sites is Middle Pleistocene, perhaps 200,000 years old. Again, there are only preliminary reports; however, certainly sufficient evidence exists in the general region that spawned early Americans to call into question the basic assumption that the initial occupation of Beringia occurred only after 15,000 years ago.

Turner's conclusion from his study of teeth that the earliest Americans came from North China is well founded, although these people evidently reached Beringia long before 15,000 years ago. If the new site near the Bering Straits is confirmed, people were already there by 35,000 years ago, when the climate was still much as it is now before the Last Glacial maximum. The presence of people in Japan, north China, and even in north central Siberia by 200,000 years ago means that people could have been anywhere in Northeast Asia during the Last Interglacial, when it was warmer than now. If people were already adapted to mainland Northeast Asia and to the Japanese islands early in the Last Interglacial, people could have been in position to traverse the Bering land bridge either as pedestrians or to skirt the coast with simple watercraft whenever the sea level dropped as much as 48 m., an event that occurred several times during the Pleistocene, including about 70,000 years ago (Hopkins 1982). If initial entry onto the Bering land bridge occurred about 70,000 B. P., the people would have been at a late transitional Homo sapiens stage, but not yet fully modern. Also, the level of technology would have been late east Asian Middle Palaeolithic, with a core and flake tool industry that may have lacked bifacial flaking. If these early people had expanded north-westward from forested parts of east Asia, they could have had a simple repertoire of minimally retouched flakes used to work a well developed technology of wood, fibre, and other perishables which would not preserve in most archaeological contexts.

We now know that people must have had watercraft sufficiently well developed to cross up to 70 km of ocean in order to populate Australia and New Guinea at least by 40,000 years ago, and even the Solomons, New Ireland (Jones l990), and perhaps Okinawa by 30,000 B. P. If people were on the island of Honshu by 200,000 years ago, it can be assumed that they were experimenting with watercraft and were capable of crossing similar expanses of water in the north Pacific to populate Hokkaido, the Kuriles, and on to Kamchatka by 70,000 years ago. A maritime north Pacific ecosystem with abundant fish, shellfish, birds, and sea mammals as well as berries and other edible plants would have presented a more productive ecosystem for early people to adapt to than the continental interior of the land bridge, where game was more mobile and more scattered, and edible plants were rare. Thus, it seems more likely that the first people who traversed the land bridge hugged the relatively warm and more productive north Pacific coast, carrying with them a relatively simple Middle Palaeolithic flake and core tool technology. Only later did pedestrian big game hunters venture across the cold and arid continental interior of Beringia after they had developed a specialized flaked stone technology.

A set of assumptions which is better able to explain available archaeological data throughout the Americas can now be formulated:

(l) Complete replacement of all populations of evolved Homo erectus by fully modern Homo Sapiens Sapiens did not occur throughout all of Eurasia. It is assumed that a late transitional east Asian Homo Sapiens entered America and evolved into fully modern Homo Sapiens Sapiens in America;

(2) Analogously, Lower Palaeolithic technologies gradually evolved through Middle Palaeolithic to an Upper Palaeolithic stage of specialized and standardized tools, including bifacial points, in certain relatively open grassland ecosystems where people devised advanced techniques for hunting herbivores which ran in herds with predictable habits. In contrast, a technological stage recognizable as Upper Palaeolithic never evolved in many densely forested areas where isolated animals could be hunted most effectively with nets, traps, slingstones, and wooden spears sometimes mounted with simple bone or stone flake tips. This is why the Upper Palaeolithic is readily recognized in the open steppe and savannah grassland regions of northern Eurasia but is difficult to define in heavily forested Southeast Asia. By analogy, it can be assumed that specialized flaked stone technologies, including bifacial projectile points, evolved in and can most readily be recognized in open grassland ecosystems of the Americas, but will continue to be difficult to define in densely forested areas because most hunters normally used other devices for killing forest animals. It can further be assumed that a coastal adaptation that did not involve the hunting of terrestrial herd herbivores may not include bifacially flaked stone projectile points;

(3) It is quite possible, even likely, that general hunters and gatherers well adapted to an ecosystem that did not require a technology including bifacially flaked stone projectile points would develop such weapons as they adapted to an inland ecosystem that included herds of large herbivores that could most effectively be hunted at certain localities using stone tipped projectiles that more easily penetrated thick hides than wooden spears;

(4) That coastally adapted people who expanded onto the land bridge early in the Last Glacial after 70,000 years ago had ample time gradually to expand their territory along the productive coastal strip of the Northeast Pacific and reach south of the region before it became heavily glaciated after 25,000 years ago. Expansion occurred by small groups who budded off and occupied familiar hunting territory, but they maintained social and sexual relationships with their relatives who still lived in the old homeland. Some descendants of these early maritime-adapted people would have remained in Beringia until rising sea levels and advancing glaciers restricted them to unglaciated refugia like the Queen Charlotte Islands or forced them inland up the Yukon River or smaller rivers that ran into the Cook Inlet. Thus, the interior of Alaska and Yukon could have been peopled from the Pacific Coast, although possibly the Athabaskan Indians are descendants of interior Siberian Upper Palaeolithic hunters who brought with them the specialized wedge-shaped core and microblade technology that much later spread eastward across the tundra with the proto-Eskimos and the boreal forest west of Hudson Bay with the Athabaskan Indians.

(5) It is assumed that the immediate ancestors of Clovis people had not traversed the ice-free corridor. Rather, the concentration of fluted points in the Southeast suggests that Clovis technology most likely developed in the littoral region of the Gulf of Mexico.

(6) It is assumed that Clovis was not the earliest cultural manifestation in sub-glacial North America, but rather represents only one of several early adaptations to inland ecosystems.

Reasons for stating the last two assumptions can be summarized. Although a wedge-shaped core, microblades, and a burin have been excavated from Bluefish Caves, Yukon, with butchered mammoth and caribou bones that dated between 15,000 and 24,000 B. P., the exceedingly widespread microblade technology was not part of the Clovis technology, even though Clovis people hunted caribou along the Southeast margins of the Laurentide glacier about 11,000 B. P. If Clovis people had migrated through the corridor from Yukon, surely they would have continued to use microblades to hunt caribou. Furthermore, the earliest known sites in the ice-free corridor, although contemporary with fluted points at 10,500 to 11,000 B. P, contain an abundant flake industry but no bifacial projectile points. Farther north in the corridor, a squat fluted point found with modern bison dated 10,500 B. P. suggests that the makers of fluted points were moving north through the corridor. The presence of willow-leaf-shaped and stemmed projectile points in contexts dated between 10,000 and 13,000 B. P. in the Great Basin, and a unifacial flake industry at Meadowcroft Rockshelter in Pennsylvania at least as early as 14,000 B. P. indicates that Clovis represents only one of several final Pleistocene socio-economic adaptation to diverse North American ecosystems, and that not all of these assemblages contain bifacially flaked stone projectile points.

If the first Americans were not big game hunters with a specialized bifacial technology, but rather general hunters and gatherers with a simple but effective core and unifacial flake technology that was readily adaptable to working bone, hide, wood, and fibrous plants into various kinds of tools for procuring roots, berries, fish, birds, shellfish, small- and medium-sized mammals, and the occasional large mammal that might be found weakened, mired, or otherwise easy to procure, archaeologists may expect to find on early occupation sites only a few minimally retouched flakes used for cutting and scraping, perhaps a simple core, or a hammerstone, and perhaps cut or charred bones, and charcoal and ash, if not later removed by running water. Diagnostic standardized artefacts may not be found because most would have been made of perishable materials. If most of these people were oriented to the coast, their sites would now be submerged on the continental shelf, deeply buried in alluvium, or destroyed by water action. Only a few stratigraphic contexts partly protected from running water, such as caves, rockshelters, bogs, or ponds, would preserve original cultural contexts. Otherwise, only flakes and cores, probably water-worn, would be found in beach or stream gravels; and such artefacts could easily be mistaken for naturefacts. Although there is little chance of finding the earliest sites in most regions because they are inaccessible or have been destroyed, we should expect to find a few early uneroded contexts preserved by aridity or rapid deposition.

As people explored new regions and adapted to new ecosystems by experimenting with the local flora and fauna for food and medicinal products, they created new kinds of artefacts, some of which are important for archaeologists because they are standardized and therefore diagnostic. In grassland areas where ingenious hunters realized that certain mammals that ran in herds could successfully be encountered and hunted at specific places where animals passed at predictable times on their migrations or congregated for water. Often, these migratory herd mammals were large; and it was soon realized that traditional weapons like sling or bolas stones, traps, and nets were not very effective means for killing these huge beasts, even if they were mired in soft sediments. Therefore, people experimented with mounting bone or unifacially flaked tips on their spears so that the tips could easily be replaced when broken, and eventually with bifacially flaked points which would better penetrate thick hides.

In North America, there were many natural grassland areas suitable for grazing herbivores, so when the idea of bifacial projectile points was first innovated in the Late Pleistocene in a few places, other people saw how effective these weapons were for hunting even medium-sized mammals, so they adopted the new technology, which soon spread widely across the continent. Even as the forests encroached during the early Holocene, people kept prairies open by periodic burning, so bifacial points continued to be used throughout prehistoric times for hunting deer, elk, and bison. On the Great Plains, a huge grassland area that remained open and allowed unrestricted movement of herds of bison until it was fenced in historic times, hunters continued to dispatch bison driven over cliffs and into pounds with projectile points that changed in style through time, as they did in neighbouring areas off the Plains.

Most archaeologists trained in North America therefore expect to find diagnostic projectile points to help them define archaeological cultures and cultural assemblages. Only in a few densely forested regions, notably the Northwest Coastal rain forest and some parts of the boreal forest, are sites found with few diagnostic projectile points because the prehistoric people relied more on traps, nets, and spears tipped with bone points, which only rarely preserve. The situation is quite different in Central and South America because bifacial projectile points are common only in the major grassland areas of the Andes, the pampas, and Patagonia. Mexico north of the Isthmus of Tehuantepec is part of North America, and dense forests covered only parts of the coastal strips before they were cleared for planting crops. However, beyond the Isthmus of Tehuantepec in Central and South America, tropical and alpine rain forests encroached onto most of the natural grassland areas that had been more common during the Pleistocene. Periodic burning, which commenced as soon as the forests started encroaching, kept small areas open for grazing animals, but after people started burning the tropical forests for crops along the Atlantic Coast and throughout Panama, many people abandoned bifacial points.

Last update 13/10/00