The first explorers had no maps or navigational instruments, and there has been spirited debate among sailors and scholars as to how they settled the region. Early theories ranged from mythical hero navigators who discovered new lands and returned home with sailing directions, to accidental voyagers who drifted away from islands to which they could not return. Complicating the argument was the myth of a South American origin, advocated by some 19th-century scholars and popularised in the 20th century by the archaeologist Thor Heyerdahl.
We now know that migrations were deliberate, because they involved taking the people, plants and animals needed to establish sustainable colonies. There have been many experimental voyages in replica canoes and rafts, as well as other ‘computer voyages’. Computer experiments using data for winds and currents show that the major voyages could not have occurred by drift.
Search and return
Lapita navigators explored in only one direction – south-east, against the prevailing trade winds. All island groups in island Melanesia and West Polynesia that lie in a south-east direction have Lapita settlements. None of these settlements have been found on other islands.
At predictable times each year the trade winds would reverse from south-easterly to westerly. At these times canoes could set off with the wind behind them, and explore to the east. When the winds reverted to south-easterly, a safe return could be made.
The exploration strategy was to search and return. All the occupied island groups acted as broad safety nets for returning canoes.
Survival, not speed
The human instinct for survival meant that exploration almost certainly occurred in stages, using different sailing strategies:
- Against the wind – this was the initial search-and-return voyage, to find out whether there were islands on the exposed side of the home island.
- Across the wind – once navigators had found new islands, they could then begin to sail safely across prevailing winds. They would know that on their return they could stop at these islands if they could not make it all the way home.
- Downwind – this happened at a later stage. Sailing downwind usually requires returning by a different route, and it took time for explorers to discover the intermediate islands that made these routes possible. Sailing downwind also indicated that navigators understood how to use the various weather systems.
The possible role of El Niño in Polynesian migration
During the last 5,000 years there have been periods when El Niño weather patterns became more frequent. The patterns occur when waters of the tropical eastern Pacific warm up. This causes the prevailing south-easterly trade winds to weaken, while the frequency of westerly winds increases. It is possible that El Niño made some long Polynesian canoe voyages into the east easier than they might have been during normal Pacific weather patterns. Some researchers think El Niño winds played an important part in the settling of the Pacific. They argue that more frequent westerly winds would have been indispensable, as they think that canoes lacked the ability to sail in any direction other than downwind. But this view is not supported by the very first European explorers’ descriptions of canoes – they witnessed Polynesians sailing their vessels across the wind and even slightly upwind.