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Ask the Experts
Photograph by Tim Mackrell
Geoffrey Irwin
Geoffrey Irwin is an archaeologist with the University of Auckland whose research focuses on the colonization of the Pacific and the history of New Zealand. He has conducted archaeological fieldwork in New Zealand, New Guinea, Indonesia, the Solomon Islands, and Fiji. Interested in navigation and trade networks, he has sailed across the Pacific retracing the migration routes of the first colonizers and used computer simulations to better understand how such a feat was possible.

What types of boats did the early colonizers of Near Oceania use before the arrival of the Lapita?

No one knows what boats were used during the Pleistocene—nothing survives. But most scholars and sailors think that people probably used rafts—maybe rafts made of big bamboo that grows in the western Pacific. Tools show up in the early Holocene that could have been used to hollow out logs, and so it's quite possible that dugout canoes go back that far, and there were probably canoes around in this voyaging corridor around New Guinea and so on before Lapita showed up.

What types of boats did the Lapita and their descendants use in colonizing the Pacific?

Well, there's quite a debate about the boats that were used, but we do know that everywhere that the Polynesian descendants of Lapita went in the wider Pacific we see these same basic elements of a dugout canoe, an outrigger, a steering oar, a woven sail. And interestingly, the same names for those parts of canoes were carried as well. So the same vocabulary exists in all of the islands for the parts of canoes which were distributed by those early colonizing Polynesian colonists.

When Lapita showed up after 1500 B.C. we think that it's almost certain that they were using sailing canoes, and these sailing canoes were made from dugout logs, and the logs had their sides built up, raised with attached planks. And they had outriggers for stability so they wouldn't just roll over, and they had a woven sail, probably of pandemis leaf, that was held up by two spires. It's pretty clear that canoes of that level of sophistication were around from the time of Lapita—1500 B.C. and on.

In your research you have used computer simulations. What can they tell us about the migration and exploration patterns in the Pacific?

Computer simulations of voyaging are useful because they're fast and cheap. You can set off thousands of voyages on the computer and do them in a few seconds, and that's not like taking a real boat to sea, so you can do far more experiments on the computer than at sea. But they can't show exactly what happened. What they are useful for doing is they can give you an idea of which voyages were easy and safe and which were hard. But where computer simulations are really useful is that you can compare the results of simulations, and you can change the rules and generate different outcomes, but you can compare the simulated outcome with the real archaeological evidence. Computer simulation is really good as an experiment in interpretation of existing archaeological evidence. It's not so useful for just searching off into the blue. But they can be quite helpful in explaining how the archaeological outcome might have happened.

Can you describe how exploration from west to east was possible in the Pacific and why going in that direction was actually beneficial to colonizers sailing into the unknown?

These migrants, these people, came originally from the west, from Asia and through Melanesia and then into Polynesia. So they came from the west and then they spread east. But in the tropics the prevailing winds come from the east, and so this created difficulties for people who were going against them. However, it is well known—it's well known now and actually it was quite well known to Polynesians who spoke to some of the early Europeans like Cook—it was known that there are regular, seasonal breaks in the trade winds, and because they're seasonal, they're predictable. And in fact, there are various kinds of westerly winds that people were able to use and must have used. But even though going east was possible, it was harder. But because it was harder it was safer. It gave people the opportunity to search and then return. They could head east during a break in the trades, and then when the trades shifted again, if they hadn't found land, or even if they had found land, they could return. So they could incrementally move to the east with a strategy of search and return, and that's a better thing to do than to search and die. They may not have comprehended it in those terms, but it's kind of how it works.