Origins of Paleoindians

 refers to the ancestral peoples of modern s. They are thought to have populated around the end of the last. Their exact origins and the route and timing of their migrations are the subject of much discussion.

The Land Bridge
The (LGM) of the  occurred approximately 20,000-18,000 years ago. Extremely cold weather resulted in the formation of vast ice sheets across the Earth's northernmost and southernmost latitudes. Glaciers also formed south of the 30th parallel in the Andean Mountains along the western coast of. As the ice sheets formed, sea levels dropped worldwide. When the and Chukchi Seas had dropped some 400 feet lower than their present level, land beneath the  was exposed. This is referred to as, an ancient subcontinent that united the eastern and western hemispheres  [1 140; 2 60].

The was a treeless, grassy  over 1000 miles wide. Broad temperature fluctuations produced below-freezing nighttime conditions. kept the soil frozen year round except in the summer, when the first few inches of topsoil became waterlogged and spongy.

Several groups from Asia migrated across Beringia to enter and populate North America. The standard model includes Eurasian big-game hunters travelling across Siberia to Beringia. Other models include Southeast Asians using watercraft to skip along the, arriving in the Americas via a coastal route.

After 18,000 years ago, the world began to warm up and the ice sheets began to melt, causing sea levels to rise. Massive flooding occurred from 15,000 to 13,000 years ago, when ice dams high in the mountains were breached. By 14,000 years ago, the land bridge lay submerged beneath the Bering Strait [3 199, 206; 4 1; 5].

The Dyukhtai of Northeast Asia
Archaeological sites found in Dyukhtai Cave and other sites in the Aldan River valley have yielded remains of a culture that may be a potential Paleoindian ancestor. This culture occupied the region from 35,000-12,000 years ago. The Dyukhtai or similar Northeast Asian cultures may have entered the New World through Beringia and spread into [1 140]. It is thought that they pursued mammals such as the giant beaver, goats, elk, ancient reindeer (early caribou), horses,  camels, steppe bison, musk ox, mastodons, and woolly mammoths.

The chief characteristic of the Dyukhtai was their manufacture of microliths or s. Microblades are small flakes less than 1 1/4 inches long, with a sharp edge and a "backed" or blunted edge that could be guided with the index finger to sever meat from a carcass. Microblades could also be incorporated into composite tools such as an arrow or sickle. Thousands of microblades have been found at upper Stone Age sites. They have been found north of together with projectile points and hand-carved ivory statuettes. The earliest of several sites there has been dated at 45,000 years ago. Microblades appeared in by 20,000 during the LGM when the island was still a peninsula and reachable by land [1 144, 202; 3 189-191]. Microblade manufacture was an important event in human history and their appearance corresponds roughly to the end of the Middle Paleolithic 60,000 years ago. Over 98% of all human history is encompassed by the period of time that began with the appearance of Australopithecus afarensis [e.g. "Lucy"]--a maker and user of Oldowan chopper tools--and ended with the manufacture of microblades by lower-upper Stone Age cultures such as the.

Southeast Asians: Paleoindians of the Coast
The boat-builders from Southeast Asia may have been one of the earliest groups to reach the shores of. One theory suggests men in boats followed the coastline from the Kurile Islands to down the coasts of North and South America as far as  [2 62; 7 54, 57]. The Haida nation on the Queen Charlotte Islands off the coast of may have originated from these early Asian mariners between 25,000 and 12,000. Early watercraft migration would also explain the habitation of coastal sites in South America such as Pikimachay Cave in by 20,000 years ago and Monte Verde in Chile by 13,000 years ago [6 30; 8 383].


 * "'There was boat use in Japan 20,000 years ago,' says Jon Erlandson, a  anthropologist.  'The  (north of Japan) are like stepping stones to Beringia,' the then continuous land bridging the Bering Strait. Migrants, he said, could have then skirted the tidewater glaciers in Canada right on down the coast." [7 64]

The Paleo-Arctic
The manufacture of microliths and composite tools from 27,000-7,000 is known as the Northeast Asian-Northwest American Microblade Tradition (NAMANT) or the Paleo-Arctic tradition. This was the first stage in colonization of the Arctic and included both continents. The Paleo-Arctic tradition contained elements from both southeast Asian boat-building and northeast Asian microblade technologies.

The Paleo-Arctic tradition diffused into North America by 14,000 when the earliest inhabitants of the began to exploit the coast for fish and sea mammals. Paleo-Arctic (or Stage 1) sites include (>7,000) on  in the Aleutian islands chain, Onion Portage (15,000), and Old Crow Flats (29,000) in the Yukon just east of the Alaskan border [6 34, 45-46].

Many languages and dialects were spoken on both sides of the Bering Strait around 14,000. The Asian Paleo-Arctic tradition would eventually give rise to the modern maritime hunting and gathering cultures of the Koryak, Tungas, Chukchee, and. The American Paleo-Arctic tradition appears to have diverged into at least two groups--the Aleuts and Inuit of the Arctic and the Paleoindians.

The Aleuts and Inuit
One group adapted to the rich resources that could be harvested from the sea. These Upper Stone Age hunters set microblades into grooves on bone points, hafted them onto various types of shafts, and used them to hunt seals, whales, and caribou [3 195-196; 6 34, 45-46]. They were probably the first people on earth to build watercraft by covering wooden frames with sealskins.

The Paleolithic ended by 10,000 and, in the New World, was followed by the Middle Lithic. By the end of the Middle Lithic in 7,000, small isolated settlements had appeared on the Aleutian Islands, the, and on both sides of the Seward Peninsula. After 4,500, continued melting of the polar ice cap opened the arctic waters and permitted widespread settlement along the ring from Alaska to. This culture of arctic dwellers would eventually become the Aleuts and Inuit--modern hunters and fishers of the Arctic [6 43-44, 46].

The Paleoindians
The Wisconsin ice sheet that covered Canada was almost 2 miles thick and blocked any movement through the interior by Paleo-Arctic dwellers. By 12,000, it had broken up into two smaller ice sheets--the Cordilleran and the Laurentide. This formed the --an ice-free passage from Alaska to the Montana-North Dakota border. Paleo-Arctic populations that remained on the Arctic coast were generally more adept at hunting sea mammals and fishing than those who pursued caribou, mammoths, and other terrestrial mammals into the interior once the McKenzie corridor opened [2 60, 62; 3 206].


 * "Paleoindians are thought to have lived primarily as small, mobile groups of big game hunters." [9 129]

Paleoindians travelled light and moved frequently--they were always moving to find new sources of plant foods and wild game. They did not carry much food and their tool kit of microblades was easily transported. Their diet was often sustaining and rich in protein due to successful hunting.

A highly mobile people such as the Paleoindians, probably had a surprisingly high reproductive rate. Travelling light during frequent moves was a more efficient utilization of calories than hunting and foraging further and further away from more permanent encampments. Paleoindians could carry more and provide for more children on the move than if they had built permanent settlements. In the bottleneck of, their birth rate decreased when "new" hunting grounds were found already populated by other bands. This slowed their progress and allowed the higher costs of more permanent residence to accumulate [10 501-504].

The Paleoindians may have moved every 3-4 days and covered 150 to 200 miles a year [10 501-502]. A thin population of humans spread over both Americas by 11,000 when the Clovis culture appeared in the Southwest. Paleoindians are generally associated with Clovis spearpoints that were hafted to darts and hurled from atlatls at the last mammoths on earth. Clovis culture was gone in 300 years but the stage had been set for the appearance of the earliest American Archaic Indians [3 205, 210].

Paleoindian Genes
The gene pool of Paleoindians (and today's Native Americans) may have also received contributions from ancestors of the present-day. The Ainu are an ancient culture of hunters, gatherers, and farmers who still live on the Japanese island of and the Kurile Islands in the archipelago north of Japan. A small population of Ainu still survive. They possess features of both Japanese and the European Caucasoid: light complexions, wavy hair, and sturdy bodies [7 54].

In addition to the Ainu, other present-day hunter-gatherer societies that have remained isolated in northeast Asia and North America and whose ancestors may have contributed to the gene pool of Paleoindian are the, Inuit, Aleut, , , Chukchi, and. However, in one anthropological study, only three groups of Gm allotypes (i.e. special blood proteins) were found in Native Americans. One group is supposedly that of the Paleoindians (which also includes thousands of Central and South American Indians) and the second is that of the Inuit and Aleuts. Another study involving mitochondrial DNA suggests a single founding tribe diverged into 4 specific mtDNA lineages responsible for 95% of all Amerindian genotypes. These 4 lineages may have roots in present-day Siberian,, and Tibetan populations. A fifth lineage known as has been associated with European or  populations [3 204; 11 226-227; 10 56-58].

The most telling physical evidence for the ancestry of the first Americans is a unique "shovelling" of the two central upper incisors. The posterior surface of the teeth is hollowed like a shovel and referred to as sinodonty. is common amongst populations of Native Americans in North, Central, and South America; and in (from the Caspian Sea to the Gobi Desert), Southeast Asia, the Pacific Islands, and Siberia. A population of from  are also classified as sinodonts.

Opposed to sinodonty, sundadonty is found from Africa to and. Most prehistoric North and South American human remains display a common Asian ancestry, although exceptions include skulls found in Minnesota dated to about 8,500 years. The well-known remains are thought to exhibit sundadonty. [3 196-198, 233, 236; 7 53, 55].