remained the one with by far the smallest population. With a mere 1,000,000 people, New Guinea could not develop the technology, writing, and political systems that arose among populations of tens of millions in China, the Fertile Crescent, the Andes, and Mesoamerica. New Guinea's population is not only small in aggregate, but also fragmented into thousands of micropopulations by the rugged terrain: swamps in much of the lowlands, steep-sided ridges and narrow canyons alternating with each other in the highlands, and dense jungle swathing both the lowlands and the highlands. When I am engaged in biological exploration in New Guinea, with teams of New Guineans as field assistants, I consider excellent progress to be three miles per day even if we are traveling over existing trails. Most highlanders in traditional New Guinea never went more than 10 miles from home in the course of their lives. Those difficulties of terrain, combined with the state of intermittent warfare that characterized relations between New Guinea bands or villages, account for traditional New Guinea's linguistic, cultural, and political fragmentation. New Guinea has by far the highest concentration of languages in the world: 1,000 out of the world's 6,000 languages, crammed into an area only slightly larger than that of Texas, and divided into dozens of language families and isolated languages as different from each other as English is from Chinese. Nearly half of all New Guinea languages have fewer than 500 speakers, and even the largest language groups (still with a mere 100,000 speakers) were politically fragmented into hun- YALI'SPEOPLE • 307 dreds of villages, fighting as fiercely with each other as with speakers of other languages. Each of those microsocieties alone was far too small to support chiefs and craft specialists, or to develop metallurgy and writing. Besides a small and fragmented population, the other limitation on development in New Guinea was geographic isolation, restricting the inflow of technology and ideas from elsewhere. New Guinea's three neighbors were all separated from New Guinea by water gaps, and until a few thousand years ago they were all even less advanced than New Guinea (especially the New Guinea highlands) in technology and food production. Of those three neighbors, Aboriginal Australians remained hunter-gatherers with almost nothing to offer New Guineans that New Guineans did not already possess. New Guinea's second neighbor was the much smaller islands of the Bismarck and the Solomon Archipelagoes to the east. That left, as New Guinea's third neighbor, the islands of eastern Indonesia. But that area, too, remained a cultural backwater occupied by hunter-gatherers for most of its history. There is no item that can be identified as having reached New Guinea via Indonesia, after the initial colonization of New Guinea over 40,000 years ago, until the time of the Austronesian expansion around 1600 B.C. With that expansion, Indonesia became occupied by food producers of Asian origins, with domestic animals, with agriculture and technology at least as complex as New Guinea's, and with navigational skills that served as a much more efficient conduit from Asia to New Guinea. Austronesians settled on islands west and north and east of New Guinea, and in the far west and on the north and southeast coasts of New Guinea itself. Austronesians introduced pottery, chickens, and probably dogs and pigs to New Guinea. (Early archaeological surveys claimed pig bones in the New Guinea highlands by 4000 b.c., but those claims have not been confirmed.) For at least the last thousand years, trade connected New Guinea to the technologically much more advanced societies of Java and China. In return for exporting bird of paradise plumes and spices, New Guineans received Southeast Asian goods, including even such luxury items as Dong Son bronze drums and Chinese porcelain. With time, the Austronesian expansion would surely have had more impact on New Guinea. Western New Guinea would eventually have been incorporated politically into the sultanates of eastern Indonesia, and metal tools might have spread through eastern Indonesia to New Guinea. But— that hadn't happened by A.D. 1511, the year the Portuguese arrived in the 3 O 8 • GUNS, GERMS,and steel Moluccas and truncated Indonesia's separate train of developments. When Europeans reached New Guinea soon thereafter, its inhabitants were still living in bands or in fiercely independent little villages, and still using stone tools. while the new Guinea hemi-continent of Greater Australia thus developed both animal husbandry and agriculture, the Australian hemi-continent developed neither. During the Ice Ages Australia had supported even more big marsupials than New Guinea, including diprotodonts (the marsupial equivalent of cows and rhinoceroses), giant kangaroos, and giant wombats. But all those marsupial candidates for animal husbandry disappeared in the wave of extinctions (or exterminations) that accompanied human colonization of Australia. That left Australia, like New Guinea, with no domesticable native mammals. The sole foreign domesticated mammal adopted in Australia was the dog, which arrived from Asia (presumably in Austronesian canoes) around 1500 b.c. and established itself in the wild in Australia to become the dingo. Native Australians kept captive dingos as companions, watchdogs, and even as living blankets, giving rise to the expression 'five-dog night' to mean a very cold night. But they did not use dingos / dogs for food, as did Polynesians, or for cooperative hunting of wild animals, as did New Guineans. Agriculture was another nonstarter in Australia, which is not only the driest continent but also the one with the most infertile soils. In addition, Australia is unique in that the overwhelming influence on climate over most of the continent is an irregular nonannual cycle, the ENSO (acronym for El Nifio Southern Oscillation), rather than the regular annual cycle of the seasons so familiar in most other parts of the world. Unpredictable severe droughts last for years, punctuated by equally unpredictable torrential rains and floods. Even today, with Eurasian crops and with trucks and railroads to transport produce, food production in Australia remains a risky business. Herds build up in good years, only to be killed off by drought. Any incipient farmers in Aboriginal Australia would have faced similar cycles in their own populations. If in good years they had settled in villages, grown crops, and produced babies, those large populations would have starved and died off in drought years, when the land could support far fewer people. The other major obstacle to the development of food production in YALI'SPEOPLE • 309 Australia was the paucity of domesticable wild plants. Even modern European plant geneticists have failed to develop any crop except macadamia nuts from Australia's native wild flora. The list of the world's potential prize cereals—the 56 wild grass species with the heaviest grains— includes only two Australian species, both of which rank near the bottom of the list (grain weight only 13 milligrams, compared with a whopping 40 milligrams for the heaviest grains elsewhere in the world). That's not to say that Australia had no potential crops at all, or that Aboriginal Australians would never have developed indigenous food production. Some plants, such as certain species of yams, taro, and arrowroot, are cultivated in southern New Guinea but also grow wild in northern Australia and were gathered by Aborigines there. As we shall see, Aborigines in the climatically most favorable areas of Australia were evolving in a direction that might have eventuated in food production. But any food production that did arise indigenously in Australia would have been limited by the lack of domesticable animals, the poverty of domesticable plants, and the difficult soils and climate. Nomadism, the hunter-gatherer lifestyle, and minimal investment in shelter and possessions were sensible adaptations to Australia's ENSO-driven resource unpredictability. When local conditions deteriorated, Aborigines simply moved to an area where conditions were temporarily better. Rather than depending on just a few crops that could fail, they minimized risk by developing an economy based on a great variety of wild foods, not all of which were likely to fail simultaneously. Instead of having fluctuating populations that periodically outran their resources and starved, they maintained smaller populations that enjoyed an abundance of food in good years and a sufficiency in bad years. The Aboriginal Australian substitute for food production has
