Polynesian Migration

The origin of Polynesians, an isolated population spanning hundreds of miles of ocean and islands, has long been regarded as an interesting puzzle in human migration patterns. Today, however, strong linguistic, cultural, and archaeological evidence from research in both the physical and social sciences points to colonization originating in Southeast Asia or Indonesia. Despite predominant easterly winds in the subtropical Pacific, Polynesian navigational skills and the aid of cyclic or seasonal changes in the winds and currents enabled dispersal from the western Pacific to islands as distant as Easter Island and Hawaii. However, there is evidence of trade and contact among disparate Pacific Island societies, and it is possible that Polynesians may have come in contact with those to both their east and west.

While motives for prehistoric migration cannot be known, a number of possibilities present themselves for speculation. On an isolated island with limited resources, it is not difficult to imagine that overpopulation would occasionally occur and encourage portions of the society to migrate. According to Edwin M. Ferdon, “without population control, this was likely to become a cyclic issue" (502). Because islands have finite resources, changes in marine ecosystems or weather could easily impact food supplies and place strain on a growing society. Additionally, Polynesian society was highly stratified, and territory was divided between ari’i, or noble families. It could be speculated that disagreements between factions could have created tension, encouraging one or more families to settle elsewhere, and that one “noble” family’s “subjects” would follow. However, we must exercise caution when attempting to speculate or oversimplify motives for such distant historical events. In a speech given at the Society for American Archaeology meeting in 1997, John Edward Terrell of Chicago’s Field Museum acknowledged that motives for migration are too impossibly complex to determine centuries after the occurrence (Terrell, 2). He further elaborates on the multitude of factors involved, suggesting that “we should expect to find, among other things, that human cognitive processes of planning, decision-making, collective action and the like must have been part of what happened, e.g. when people were "responding to population pressure." Put simply, prehistoric human colonization was social as well as biological, active as well as passive” (Terrell, 3). In short, the reasons that Pacific peoples dispersed from west to east may never be known, given the complexity of human decision making; there were probably a host of factors involved, including a limitation of resources but also including various other socio-emotional reasons.

Polynesians likely originated from the Lapita people, who originated in Melanesia, the region north of Australia that includes the modern countries of Papua New Guinea, Fiji, Vanuatu, the Solomon Islands, and New Caledonia. The first people arrived in the Western Pacific areas of Australia and New Guinea at least 50-60,000 years ago, according to Terrell (Terrell, 5). Archaeology suggests that the migration eastward occurred in roughly two waves, the first occurring in the Bismarck Archipelago, Samoa and Tonga from 1600–1200 BC, and the second occurring later and spreading to the outer reaches of the Polynesian Triangle, bordered by Hawaii, Easter Island and New Zealand. While these islands are separated by thousands of miles of open ocean, Pacific islanders’ methods of sailing and navigation were likely well-developed and quite accurate. Andrew Lawler of Science magazine describes Polynesians as “the great premodern seafarers” who used “sails and sophisticated navigation techniques [to] peopl[e] most South Pacific Islands” (1344), and Marshall Weisler notes that “nearly every inhabitable island was occupied by AD 1000” (Weisler 2, 1881). Terrell reminds us that “people had been sailing around the Solomons and the islands of the Pacific to the west of that archipelago for a very long time” before the first migration (Terrell, 6). While it is not entirely clear when specific voyages occurred, it seems that ancient Polynesians were an active and curious people, perhaps with “wanderlust and a sense of adventure” (Terrell, 6), who had explored the area a good deal before sailing off to emigrate.

Cultural and linguistic evidence further supports the west-to-east migration pattern, with striking similarities observed across the Polynesian Triangle. The path of the Lapita is marked by pottery with distinct geometric designs found in more than 200 South Pacific locations, from Papua New Guinea to Samoa (Field Museum). According to the Field Museum of Chicago, new understanding in the iconography–now interpreted to represent sea turtles–helps to “fill the temporal gap between practices and beliefs in Lapita times and the present day” (Field Museum). Researchers at the museum now believe the “ceramic portraits” could be “ways of expressing religious ideas held by early Pacific Islanders” (Field Museum), which helps explain the significance of the design and supports the hypothesis that Pacific Islanders originated from a single people. Furthermore, according to an article by Bruce Bower published by Science News, “the artistic motifs on the pottery are much the same as Polynesian tattoo styles that occurred centuries later” (Bower, 233). The similarity in iconography is unlikely to be coincidental, especially if it had religious significance, because this suggests a coherent belief system that may have spread as a whole. Cultural similarities, such as the presence of outriggers on canoes from New Zealand to Melanesia to the Society Archipelago, also point to a shared ancestry. People across the Pacific also speak similar Austronesian languages, which Terrell describes as “the inheritance of ancestral characteristics by the direct biological, cultural and linguistic descendants of the people who first started speaking in these ways” (Terrell, 4). Essentially, the similarities observed in Polynesian peoples across the Pacific, including building styles and language, suggest common ancestry.

While the prevalent wind direction in the eastern tropical Pacific is easterly, seasonal and cyclic anomalies based on El Niño periodically enable travel from west to east. Ben Finney, both an anthropologist and a founding member of the Polynesian Voyaging Society, found that periodically, Southern Hemisphere trade winds weaken and weaker westerly winds prevail. During El Niño events, these winds may persist for longer and extend further east (Finney, 402). While the most obvious wind patterns would seem to contradict the Lapita ancestry model, prehistoric islanders could indeed have sailed west to east if they waited for seasonal or periodic changes. Finney conducted an experimental voyage of his own to test this assertion, and found the winds to be generally quite amenable to his travel from Samoa to Tahiti. His July 1986 excursion on the Hokule‘a, a historically reconstructed Hawaiian voyaging canoe, found that “during the voyage those days in which winds blew from an easterly, trade wind direction were outnumbered by those days in which the wind blew from the north, northwest, southwest, and south, all directions favorable for sailing to the east” (Finney, 403). While the 1986 winds were unusual, Finney estimates similar patterns in one of ten years (Finney, 405), and given that the migration across the Pacific took place across hundreds of years, this is a more than sufficient frequency for these so-called “anomalous westerlies” to have played a role in dispersal.

Artifacts created from volcanic rocks can be traced back to their sources using both design of the object and chemical composition. This is especially true of fine-grained basalt, which can be traced to its geologic source, further linking the various regions of the Pacific and supporting the Lapita-migration model. According to Patrick V. Kirch and Robert Green, whose study of cultural evolution in Polynesia was published in Current Anthropology, “the tribes, societies or ethnic groups of ‘Triangle Polynesia’ share a physical type, systemic cultural patterns, and historically related languages which allow them to be grouped together as a unit of historical analysis or … a phylogenetic evolutionary unit” (Kirch and Green, 164). Stone tools are an important element of the “systemic cultural systems,” and similarities across the Pacific can be tracked. Specialized stone adzes were used by prehistoric islanders in Melanesia for a variety of purposes, including cutting down trees for canoe-building, hollowing out built canoes, and even clearing vegetation for agriculture (Clark, 19). Adzes used for each purpose had distinctive shapes, and similar styles were found across the region. Clark also notes that only a few quarry sites existed, and that “quarries of favorable stone served considerable areas of country” (Clark, 21). Furthermore, at least in Maori society, “the exchange of commodities between one group and another, despite their bellicosity and rivalry, was well-developed.” (Clark, 24). Clark highlights the existence of trade and the transport of goods from one island to another, and while he does not explicitly argue for the existence of inter-island exchange of people it is not difficult to imagine that this would exist among a people for whom trade was so well-established.

Geochemists have been able to place basaltic artifacts in both time and place, further clarifying the accepted narrative of migration from west to east. Many Polynesian artifacts are crafted from obsidian, which “has a restricted natural occurrence yet was transferred great distances” (Weisler 2, 1881), which makes it a relatively easy rock to trace. Anthropologist Marshall Weisler’s “Hard Evidence for Prehistoric Interaction in Polynesia” uses x-ray fluorescence and analysis of chemical factors such as alkali composition and extent of melting and cooling to divide a cross-section of basaltic artifacts into categories, which likely correspond to rough source locations. Magma is formed when source rock melts and partially cools, and a volcano produces a specific combination of melting and cooling that creates a distinct chemical “signature” (Weisler, 526). Thus, the magma’s chemical properties bear a stamp of sorts that provides clues to its source, and rocks from the same volcano are likely to have similar chemical properties. Using these methods, Weisler was able to cluster artifacts found in various locations on the Society Islands and Mangareva to specific source sites: Eiao in the Marquesas, and Mata’are in the Cook Islands (Weisler, 526 – check.) A second Weisler study used ratios of lead isotopes to further analyze the geochemistry, a method that may result in more accurate placement of artifacts in place and time. Because this method takes both chemical ratios in the mantle and the age of the rock into account, it is able to narrow possible obsidian sources further than the previous method (Weisler 2, 1882). While research is still in progress, preliminary results have traced adzes found on Henderson Island clearly to a source on Pitcairn, and one to the Gambier Islands (Weisler 2, 1884). While Weisler’s geochemical analysis is as yet in its early stages, it has already provided evidence for prehistoric inter-island transport and opens up doors to promising future research.

Similarly, biological researchers have been able to link settlements through the remains of animals introduced by voyagers, particularly the Polynesian rat (R. exulans). The rat, which cannot swim and cannot disperse to islands without the help of humans, was believed to be brought along on voyages as a food source (Robins, 1). The DNA of animal bones can be analyzed, and researchers E. Matisoo-Smith and J.H. Robins were able to separate remains into three major haplogroups that are divided into distinct geographic locations (Robins, 2). Most relevant, Haplogroup III was found exclusively in an area designated “Remote Oceania,” which includes Polynesia (citation). APPENDIX: FIGURE 2

The Polynesian peoples themselves provide clues to their prehistoric origins via DNA testing. A study conducted by J. Koji Lum et al. in 1994 identified three distinct gene clusters shared by most Polynesians in the study. The researchers used blood samples of subjects from a variety of ethnicities, including Hawaiian, Samoan, Tongan, Micronesian, Indonesian, Malay, Chinese, Japanese, Thai, Cambodian, Burmese, Hmong, Aborigine, and Papua New Guinean, as well as “control groups” of Africans and Europeans (Lum, 569). The group found common genetic mutations among about 30-40% of East Asians and nearly all Polynesians and many Hawaiians studied (Lum, 571). The researchers grouped subjects’ DNA into three “major lineage clusters,” all of which share common nucleotide deletions or substitutions. Subjects with the three clusters live in geographic clusters as well. The first subjects are from Hawaii, Samoa, Tonga, and Micronesia; the second are from Hawaii and Samoa; and the third are from French Polynesia, with one Samoan subject sharing similar DNA (Lum, 576-577). The common DNA, which is spread across the Pacific, suggests common ancestry of research subjects despite their East-West Pacific divide. For example, the presence of similar genetic mutations in Hawaiians and Samoans suggests common family lineages in two geographically distant places. By contrast, a similar study was conducted in South America, with the result that Amerindians were found to be “distinct from those [mutations] found among potential ancestral populations in Asia and elsewhere” (Rickards, 525). The combination of these two studies strongly implies that Polynesians are descended from Melanesians and more distantly from Southeast Asians, but are genetically distinct from indigenous South Americans in locations such as Peru and Colombia.

Prior to the existence of scientific evidence such as DNA and geochemical analysis, speculation regarding Pacific Islanders’ origins often suggested origin in the Americas, based on certain cultural and biological similarities between the two regions’ indigenous societies. Because migration from South America to the Polynesian Islands would be easily facilitated by prevalent easterlies in the tropical Pacific, several prominent scholars made claims that islanders were descended from ancient Peruvians or other Amerindian peoples. Thor Heyerdahl’s Kon-Tiki is perhaps the best known of these “studies,” but while Heyerdahl’s work was widely publicized, his methods and lack of professional expertise undermined his conclusions. Heyerdahl constructed a raft of balsa wood based on historical accounts of “Peruvian reed-boats,” which bore some similarities to a “rudimentary ‘raft-ship’” found in Tahiti (Heyerdahl, 23). The author and a small crew, with neither sailing experience nor archaeological training, embarked on a voyage from Peru to Tahiti in 1947 that met with remarkably positive results. The men were able to fish for food and obtain rainwater from storms; the decidedly unseaworthy balsa wood held together quite well; and the predominant easterlies blew the voyagers quite directly to Polynesia. Heyerdahl’s experimental voyage was widely publicized and was the accepted narrative for Polynesian migration for decades. However, while he proved that such a voyage could theoretically occur, he lacked evidence to prove that such a voyage in fact had occurred. Science magazine’s Andrew Lawler wrote a scathing critique of Heyerdahl this past year, accusing Heyerdahl of “souring academia” and of publicizing the “racist assumptions” that Polynesians’ ancestors had traveled from the Middle East to South America to the Pacific, “where they bestowed civilization on dark-skinned peoples” (Lawler, 1345). Heyerdahl’s theories were based largely on speculation and original thought; however, his daring journey and engaging narrative caught the eye of the public and convinced many intelligent people that South Americans and Polynesians were in fact related. The Mormon Church has also spread the idea of east-west migration. According to a 1992 BYU publication, “A basic view held by the Church is that Polynesians have ancestral connections with the Book of Mormon people who were descendants of Abraham and that among them are heirs to blessings promised Abraham’s descendants” (1110). The church teaches that “among Polynesian ancestors were the people of Hagoth, who set sail from Nephite lands in approximately 54 BC“ (1111). Given the Church’s prominent evangelization efforts in Polynesia, as well as its active media presence, its propagations of these beliefs are influential. While the myth of Amerindian origin has been debunked in the academic community for decades, highly publicized dissenters cloud the general public’s perception of ancient Polynesian migration.

While west-to-east migration is nearly universally accepted in the academic world, there is some interesting evidence suggesting prehistoric contact, if not migration, between Pacific Islanders and Amerindians in modern-day Peru. The presence of sweet potatoes in Polynesia, for example, which are native to South America, suggests that the two civilizations must have had some interaction. Additionally, Finney’s article, as previously discussed, introduces the idea of variable wind patterns in the eastern tropical Pacific that could have enabled sailing from Polynesia to South America; conversely, the prevalent easterlies would easily have facilitated return home (Finney, 405). The author even suggests that Polynesians may have willingly explored the east with this knowledge, and “may have welcomed the appearance of such westerly winds in the hurricane-free months, and then used them to explore to the east to find out what islands rise out of the sea in the direction from which the trade winds blow” (Finney, 405). Much of the evidence sensationalized by Kon-Tiki can also be used to support prehistoric contact; while Heyerdahl did not have sufficient proof to back up his claims, biological and cultural similarities between the two regions may suggest trade or other short-term voyaging.

A plethora of evidence, ranging from geologic sourcing to archaeological records, from DNA sequencing to cultural and linguistic similarities, supports the theory of west-to-east migration across the Pacific. This was believed to occur over centuries, among a seafaring people known for their exploration and skilled knowledge of their oceanic environment. Contrary to past theories of chance arrivals on islands, and the idea that Polynesians were descended from Americans, the similarities among Melanesians, Asians and Polynesians in their culture and shared archaeological record are quite conclusive.

Allison Gramolini, Colgate University
2011

 

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