A DNA survey of wild and domestic pigs has thrown new light on how early humans reached the remote Pacific.
The findings contradict established theories on Pacific migration
Scientists from Durham and Oxford Universities have found a clear genetic link between modern and ancient pigs in East Asia and several Pacific islands.
This suggests that colonists who transported the animals may have travelled from Vietnam via numerous islands, according to the researchers.
Details appear in Proceedings of the National Academy of Sciences journal.
During the study mitochondrial DNA was obtained from the jaw bones or teeth of modern and ancient pigs across East Asia and the Pacific.
Studies of the samples revealed a single genetic heritage shared by modern Vietnamese wild boar and modern feral pigs on the islands of Sumatra, Java, and New Guinea.
The same link was also found between Ancient Lapita pigs in Near Oceania, and modern and ancient domestic pigs on several Pacific Islands.
The findings contradict established theories that colonists originated in Taiwan or Island Southeast Asia, and travelled along routes that pass through the Philippines as they dispersed into the remote Pacific.
Research project director, Dr Keith Dobney, from the Department of Archaeology at Durham University, said: "Many archaeologists have assumed that the combined package of domestic animals and cultural artefacts associated with the first Pacific colonizers originated in the same place and was then transported with people as a single unit.
"Our study shows that this assumption may be too simplistic, and that different elements of the package, including pigs, probably took different routes through Island South East Asia, before being transported into the Pacific."
Dr Greger Larson, lead author of the paper, performed the genetic work while at the University of Oxford.
He said: "Pigs are good swimmers, but not good enough to reach Hawaii. Given the distances between islands, pigs must have been transported and are thus excellent proxies of human movement.
"In this case, they have helped us open a new window into the history of human colonization of the Pacific."