Kelp Highway Hypothesis

Bull Kelp Forest, Vancouver Island, Canada
Boomer Jerritt / All Canada Photos / Getty Images

The Kelp Highway Hypothesis is a theory concerning the original colonization of the American continents. Part of the Pacific Coast Migration Model, the Kelp Highway proposes that the first Americans reached the New World by following the coastline along Beringia and into the American continents, using edible seaweeds as a food resource.

Revising Clovis First

For the better part of a century, the main theory of human population of the Americas was that Clovis big game hunters came into North America at the end of the Pleistocene along an ice-free corridor between ice sheets in Canada, about 10,000 years ago. Evidence of all kinds has shown that theory to be full of holes.

  1. The ice free-corridor wasn't open.
  2. The oldest Clovis sites are in Texas, not Canada.
  3. The Clovis people were not the first people into the Americas.
  4. The oldest pre-Clovis sites are found around the perimeter of North and South America, all dating between 10,000 and 15,000 years ago.

Sea level rises have inundated the coastlines that the colonizers would have known, but there is strong evidentiary support for the migration of people in boats around the Pacific rim. Even though their landing sites are likely submerged in 50–120 meters (165–650 feet) of water, based on the radiocarbon dates of what would have been inland sites, such as Paisley Caves, Oregon and Monte Verde in Chile; the genetics of their ancestors, and perhaps the presence of a shared technology of stemmed points in use around the Pacific Rim between 15,000–10,000, all support the PCM.

Diet of the Kelp Highway

What the Kelp Highway Hypothesis brings to the Pacific Coast Migration model is a focus on the diet of the purported adventurers who used the Pacific coast to settle North and South America. That diet focus was first suggested by American archaeologist Jon Erlandson and colleagues beginning in 2007.

Erlandson and colleagues proposed that the American colonizers were people who used using tanged or stemmed projectile points to rely on an abundance of marine species such as marine mammals (seals, sea otters, and walruses, cetaceans (whales, dolphins, and porpoises), seabirds and waterfowl, shellfish, fish, and edible seaweeds.

>Supporting technology required to hunt, butcher and process marine mammals, for example, must have included seaworthy boats, harpoons, and floats. Those different food resources are found continuously along the Pacific Rim: so as long as the earliest Asians to start out on the journey around the rim had the technology, they and their descendants could use it from Japan to Chile.

Ancient Art of Sea Faring

Although boat-building was long considered a fairly recent capability—the oldest excavated boats are from Mesopotamia—scholars have been forced to recalibrate that. Australia, separated from the Asian mainland, was colonized by humans at least 50,000 years ago. The islands in western Melanesia have settled by about 40,000 years ago, and Ryukyu islands between Japan and Taiwan by 35,000 years ago.

Obsidian from Upper Paleolithic sites in Japan has been sourced to Kozushima Island—three and a half hours from Tokyo by jet boat today—which means that the Upper Paleolithic hunters in Japan went to the island to obtain the obsidian, in navigable boats, not just rafts.

Peopling the Americas

The data on archaeological sites scattered around the perimeters of the American continents include ca. 15,000-year-old sites in places as widespread as Oregon, Chile, the Amazon rainforest, and Virginia. Those similarly aged hunter-gatherer sites don't make much sense without a coastal migration model.

The proponents suggest that beginning somewhere between 18,000 years ago, hunter-gatherers from Asia used the Pacific rim to travel, reaching North America by 16,000 years ago, and moving along the coast, reaching Monte Verde in southern Chile within 1,000 years. Once people reached the Isthmus of Panama, they took different paths, some northward up the Atlantic coast of North America and some southward along the Atlantic South American coastline in addition to the pathway along Pacific Southern American coast that led to Monte Verde.

The proponents also suggest that Clovis large-mammal hunting technology developed as a land-based subsistence method near the Isthmus before 13,000 years ago, and spread back upward into southern-central and southeastern North America. Those Clovis hunters, descendants of Pre-Clovis, in turn, spread northward overland into North America, eventually meeting the descendants of the Pre-Clovis in the northwestern United States who used Western Stemmed points. Then and only then did Clovis colonize the finally truly Ice-Free Corridor to mingle together in eastern Beringia.

Resisting a Dogmatic Stance

In a 2013 book chapter, Erlandson himself points out that the Pacific Coast Model was proposed in 1977, and it took decades before the possibility of the Pacific Coast migration model was seriously considered. That was because, says Erlandson, the theory that Clovis people were the first colonists of the Americas was dogmatically and emphatically considered received wisdom.

He cautions that the lack of coastal sites makes much of the theory speculative. If he's right, those sites are submerged between 50 and 120 m below mean sea level today, and as a result of Global Warming sea levels are rising, so without new undreamt-of technology, it is unlikely that we will ever be able to reach them. Further, he adds that scientists should not simply replace received-wisdom Clovis with received-wisdom pre-Clovis. Too much time was lost in battles for theoretical supremacy.

But the Kelp Highway Hypothesis and the Pacific Coast Migration Model are a rich source of investigation for determining how people move into new territories.


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Hirst, K. Kris. "Kelp Highway Hypothesis." ThoughtCo, Aug. 27, 2020, Hirst, K. Kris. (2020, August 27). Kelp Highway Hypothesis. Retrieved from Hirst, K. Kris. "Kelp Highway Hypothesis." ThoughtCo. (accessed June 10, 2023).