Long before Columbus sailed to America, people traveled long distances to colonize new places. One of these movements was the Austronesian expansion, a movement of southeast Asians into Indonesia and the Philippines. Diamond believes that the Austronesians were originally South Chinese or Southeast Asians. Linguistic evidence suggests that the expansion originated in Taiwan.

Archaeological records corroborate the linguistic evidence. The archaeology indicates that people making artifacts similar to those of South China replaced hunter-gatherers in Taiwan in the fourth millennium BCE. Artifacts show that these new Taiwanese had ocean-going watercraft suitable for an outward expansion. Over the next several thousand years, their pottery styles, stone tools, pigs, and crops spread outward into the Pacific Islands. They displaced hunter-gatherer populations on most of the Philippine islands and reached many previously uninhabited islands in the Pacific Ocean. They also moved east as far as Madagascar.

Diamond proposes that the Austronesian expansion replaced the original hunter-gatherer populations of the Pacific Islands for the same reasons that Europeans replaced the people of so many other cultures. The immigrants’ tools, weapons, skills, and diseases must have helped them dominate or kill most of the people they encountered.

The Austronesian expansion reached New Guinea but did not replace all of the people there. The New Guineans of the northern highlands, who already had a good deal of agriculture and its accompanying technology, retained possession of their lands. Austronesians probably moved into the vicinity of New Guinea and traded with New Guineans. However, they were unable to accomplish a complete replacement of New Guinean society with their own.

The Austronesians seem to have had substantial advantages over the hunting and gathering people they encountered on most of the islands they occupied. On New Guinea, however, they must have found a society that was more equally matched to theirs. Ancient New Guineans already grew some of the same crops as the Austronesians, and they also had a comparatively high population density. They were, compared to the Austronesians, fairly resistant to disease. Whereas ecological difficulties probably stopped the Austronesians from invading Australia, cultural and technological factors stopped them in New Guinea.

Before Europeans arrived, the Austronesians colonized virtually all of the rest of the islands in the Pacific Ocean. When Europeans came, they only succeeded in substantially colonizing the areas that were most remote or least habitable for the Austronesians. Many of the other islands, however, remain mainly populated by the Asian people who have been living there for thousands of years. Those who retained their land did so largely because of their germs and food production abilities.