History's greatest prehistoric mariners, the Polynesians, may have first gained their sea legs in the waters between Taiwan and China, a new archaeological study has suggested.
Research into the neolithic trading of basalt tools 4,000 years ago has found evidence of longdistance voyaging between the volcanic Peng-hu islands and Taiwan.
The distances involved - at least 45km hauls - outstrip the efforts of other mariners of the time.
The discovery might explain where the Polynesians, who originated from around Taiwan and neighbouring mainland China, acquired skills that would later allow them to migrate across thousands of miles of ocean.
"Prehistoric contact between Taiwan and Peng-hu may mark the beginning of an Austronesian open-sea voyaging tradition, one that carried Lapita peoples and their Polynesian descendants to the furthest reaches of the Pacific," said Barry Rolett, an anthropologist at the University of Hawaii, United States.
While no evidence for the boats themselves remains, it is thought the traders made their perilous crossings on simple bamboo rafts. When the mariners later developed sailing outrigger canoes, they had the maritime technology required to make more daunting expeditions, reaching destinations as distant as New Zealand.
Professor Rolett and colleagues, Wei-chun Chen and John Sinton, made an X-ray fluorescence and petrographic analysis of adzes recovered from three separate Taiwanese settlements dating from as far back as 4,500 years ago.
Trace elements in the volcanic basalt that the tools were made from gave a good match to rock found on islands in the Peng-hu archipelago.
The tools are found all over Taiwan - where there are no suitable quarries for the rock - and were used for commonplace tasks such as wood working.
Professor Rolett believes this shows regular trading across the 45km stretch of sea that separates the volcanic islands from Taiwan.
Their results will be published in the journal Antiquity.