Together with a 600-year-old seafaring canoe discovered on the western New Zealand coast, new analyses of ancient wind patterns offer an extraordinary glimpse into the maritime technology and climate conditions that allowed early Polynesians to colonize islands in the South Pacific.
Archaeological evidence have previously suggested a rapid colonization of Pacific islands between 1100 AD and 1300 AD, long before Europeans explored the ocean. But how the subsequent period of ongoing maritime exploration and inter-island travel came to be has been a mystery. The pair of findings (here and here), published in Proceedings of the National Academy of Sciences this week, offer two pieces to this puzzling feat.
A trio of University of Auckland researchers led by Dilys Johns examined the remains of a canoe discovered at Anaweka on the New Zealand coast. The weathered plank is likely part of the hull of a 20-meter-long canoe that either had two hulls connected by (and supporting) a deck or had an outrigger that provided stability, Science explains. There was also evidence of repair and re-use.
Radiocarbon dating puts the canoe’s voyaging days at around 1400 AD -- making it just one of two known canoes from the early occupation of the South Pacific. Its carved interior ribs make it structurally similar to the canoe previously excavated in the Society Islands, more than 4,000 kilometers away. Its construction materials suggest it was made in New Zealand, as an early adaptation to a new environment. Finally, the hull features a carving of a sea turtle (pictured above) -- which is rare in native New Zealand art, but widespread in Polynesian culture.
In a related study, researchers may have settled a longstanding debate over whether Polynesian settlers traveled windward or used off-wind sailing. After all, the direction the winds blow these days suggests that it would have been an epic struggle to sail eastwards to Easter Island or westwards to New Zealand, New Scientist explains.
So, a team led by Macquarie University’s Ian Goodwin reconstructed paleoclimate conditions in the South Pacific from 800 to 1600 AD by mapping wind-field patterns from sea-level pressure modeled at 20-year intervals. Their results suggest that a shift in climate conditions may have enabled early Polynesians to colonize the islands using canoes that didn’t have the capability to sail windward.
Off-wind sailing between central East Polynesia and New Zealand was anomalously favorable between 1140 and 1260 AD, when the intensification and poleward expansion of the Pacific subtropical anticyclone strengthened the tradewinds toward New Zealand. A window of favorable sailing conditions to Easter Island occurred between 1250 and 1280 AD. All passages could have been made downwind over the immense ocean tracts.
The patterns also reveal how New Zealand was potentially colonized by voyagers from the Tonga-Fiji Islands, Southern Cook Islands, and Austral Islands, while Easter Island might have been colonized from both central East Polynesia and from Chile. These multiple migrations fit in with Polynesian folklore.
“These are fantastic new insights into prehistoric maritime migration,” Goodwin says in a news release, “and opens doors for marine climatologists to work with anthropologists and archaeologists, to piece together the evolution of maritime societies.”