Since pigs were domesticated and carried with at least some of the first people to settle the Pacific, the swine are an easy and accessible way to track human migration (explore an interactive atlas of human migration).
"The irony here is the best way to study humans is by studying what the humans took with them rather than the humans themselves," Larson said.
(Related news: "Rat DNA Offers Clues to Pacific Colonization, Study Says" [June 9, 2004].)
His team therefore sampled DNA from 781 modern and ancient pig specimens to trace which types of pigs wound up where.
The results suggest that one type of pig did disperse from southern China through Taiwan and the Philippines and into the islands of the western Pacific.
But other, earlier dispersals of a different kind of pig took the southern route out of Vietnam. This pig became the dominant species in the eastern Pacific.
According to Larson, the findings support the theory that, instead of an entire language and culture migrating en masse from Taiwan, each component first came together in eastern Indonesia about 3,500 years ago.
The resulting cultural complex, known as Lapita, then spread as a unit to Fiji and Tonga. The Lapita were ancestors to the Polynesians, who spread the culture to Hawaii, Tahiti, and other remote islands, Larson said.
"What's nice about the pigs is that there is a very strong argument for exactly that: that each one of these items is moving along a different trajectory" until they reach New Guinea, Larson said.
"If everything is [considered] one unit but actually it's not," Larson said, "then the oversimplification can lead to a misinterpretation of what really happened."
Pigs vs. Linguistics
Peter Bellwood, an archaeologist at Australia National University in Canberra, is a proponent of the 'out of Taiwan' model.
In an email, he said that the archaeological and linguistic evidence "make it clear that Pacific Island languages and the ancestral cultures associated with them" originated in Taiwan.
"They were not transmitted from Vietnam," he added.
He also thinks it odd that the two pig dispersals noted in the paper did not have much overlap, since the various human populations transporting the pigs would have been in constant contact.
"And this in itself warrants caution before we reject the conclusions from the past century of careful multidisciplinary research."
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