The timing and route of human arrival to mid-latitude North America is highly contested and both the terrestrial and coastal routes suffer from a paucity of archaeological evidence.
Beringia is very difficult to access in modern-day because it is now below current sea level. However, hypotheses have been made based on mitochondrial DNA research to address the question of whether or not humans left Beringia and settled mid-latitude America during the LGM or stayed in Beringia throughout the LGM.
Three-wave model The Three-wave model is an older model that attempts to explain the
peopling of the Americas suggested by Greenberg et al. (1986). Using linguistic and
genetic data as well as dental anthropology, Greenberg et al. subdivided Native Americans into three groups: Amerind,
Na-Dene, and Aleut-Inuit. They explained the linguistic, anatomical, and genetic differences they found in each group as a result of separate migrations or waves out of
Northeast Asia to the Americas. Paleoecological evidence suggests that travel along the coast would have been possible between 13 and 11 ka as the ice sheets were retreating. The coastal region was quite hospitable by 13 ka to peoples with watercraft and a maritime adaptation. Erlandson et al. (2007) suggest that coastal migrations and settlements happened in higher latitudes, such as 35-70°N, where coastal ecosystems would be more productive because of geography and
upwelling in the Northern
Pacific Rim. The different kelps of the Pacific Rim are major contributors to the areas of productivity and biodiversity and support a wide variety of life such as
marine mammals,
shellfish,
fish,
seabirds, and edible
seaweeds that would also support a coastal community of
hunter-gatherers.
Santa Barbara Channel Islands, Santa Barbara Coast's Sudden Flats, and
the Scotts Valley site, CA-SCR-177. The
Arlington Springs Man is an excavation of 10,000-year-old human remains in the Channel Islands. Further evidence to support the coastal migration hypothesis has been found in the biological viability of regions after deglaciation. Lesnek et al. 2018 found that the deglaciation of the Pacific coastal corridor allowed for biological productivity, availability of food resources, and an accessible migration route for early colonization.
Zoo-archaeological evidence Further evidence of a coastal ecology sufficient to support early coastal migrants comes from zoo-archaeological finds along the Northwest coast. Goat remains as old as 12 ka have been found on
Vancouver Island, British Columbia, as well as bear remains dating to 12.5 ka in the
Prince of Wales Archipelago, British Columbia. Dietary evidence from middens in Indonesia indicates the development of offshore fishing, requiring watercraft, between 35 and 40 ka. Sea-going cultures were mobile in the island-rich environment off the late Pleistocene coast of east Asia, facilitating the spread of marine technology and skills through the Philippines, up the Ryukyu chain, to Japan. Warming of the climate after about 16 ka (although glaciation would remain) could have provided an impetus for seaborne migration up the Kurile island chain towards North America, through some combination of a more hospitable climate and increased ocean productivity. Although no boats have been recovered from early Pacific Coast archaeological sites, this may be due to poor preservation of organic materials and the inundation of coastal areas mentioned above. We can still infer water travel based on the presence of artifacts made by humans found at island sites. Anecdotal evidence comes from the surviving
Bella Bella oral tradition, as recorded by
Franz Boas in 1898. "In the beginning there was nothing but
water and
ice and a narrow strip of shoreline." Some believe this story describes the environment of the Northwest Coast during the last deglaciation.
Migration south Further south, California's
Channel Islands have also produced evidence for early seafaring by Paleoindian (or Paleocoastal) peoples.
Santa Rosa and
San Miguel islands, for instance, have produced 11 sites dating to the Terminal Pleistocene, including the
Arlington Man site dated to ≈11 ka and Daisy Cave occupied about 10.7 ka. Significantly, the Channel Islands were not connected to the mainland coast during the Quaternary, so maritime peoples contemporary with the Clovis and Folsom complexes in the interior had to have seaworthy boats to colonize them. The Channel Islands have also produced the earliest fishhooks yet found in the Americas, bone bipoints (gorges) that date between about 8.5 and 9 ka (10,000 and 9500 calendar years). Even further south, the
Monte Verde site in Chile has become accepted as the earliest settlement in South America, dating to at least 14,500 years ago. This is believed to indicate migration through northern coastal regions before that date. The Monte Verde site produced the remains of nine types of seaweeds, including kelp. ==Western Stemmed Tradition==