Vanished Islands and Hidden Continents of the Pacific

5: The Coming of Humans to the Pacific

Our story begins in the distant past, about 40,000 years ago and perceived today only very dimly through the haze of history, when modern humans1 first encountered the Pacific Ocean. This event took place somewhere in East Asia, possibly Southeast Asia: humans had been living for perhaps the preceding 80,000 years in the wide, fertile valleys of rivers like the Changjiang (Yangtze) and Huanghe (Yellow).2 Today we might be tempted to think that these humans were traveling down those valleys to get to their mouth, but they almost certainly had no such notion. On any particular day they sought sustenance from the environment that surrounded them, sometimes following herds of animals but not persisting in following a particular direction for any less-pragmatic purpose. Also bearing in mind the comparatively low numbers of humans living in that region at the time, we can thereby understand why it apparently took them 60,000 years or so to move about 5,000 kilometers to reach the Pacific Ocean.3 Reaching the Pacific Coast When humans first encountered the Pacific Ocean, the available indications are that they did not think much of it, perceiving it as a barrier rather than an opportunity.4 We can infer that it took perhaps 10,000 years of intermittent contact with the ocean for the relationship to change significantly and for the first coastal-dwelling humans in the Pacific to come to depend on marine foods. This change may have taken place initially when humans from southern China moved south into Southeast Asia.5 In his landmark 1993 book, Self-Made Man, Jonathan Kingdon argued that (for archipelagic Southeast Asia) this lifestyle change was an important contributor to the diversification of human skin color. According to Kingdon, when humans depended only on foods available on the land, they would choose to acquire that food at cool times of the day, thereby The Coming of Humans to the Pacific 5 72 Vanished Islands and Hidden Continents of the Pacific limiting their exposure to the sun, resulting in their skin becoming, over tens of thousands of years, light brown. But when humans began gathering food from the coast, much of that was accomplished from shore-reef flats at low tide. Such locations were exposed to the sun, and people had no choice about what time of the day they visited them. As a result, such people gradually acquired darker skins than those who consumed only land foods. As people began to make more use of ocean foods, they naturally became more adept at interacting with the ocean. They devised innovative techniques for collecting marine foods, developing the technology and vessels to enable them to venture increasingly farther offshore in search of foods from deeper waters. Perhaps for many people along the coasts of the Pacific Ocean (and those of Southeast Asia) 30,000 years or so ago, a switch to largely marine food subsistence was embraced because it lacked the more manifest dangers of life on land. In the rain forests of Southeast Asia, humans, who had no special advantage at the time, needed to compete for the same foods with fierce predators like tigers; farther north in what is today eastern China these were also present, along with bears, leopards, and a now-extinct lion-sized hyena that appears to have routinely attacked humans.6 There is some evidence that the scenario just sketched is somewhat conservative in terms of its chronology. The principal evidence suggests that humans reached the Australia– New Guinea landmass at least 40,000 years ago, perhaps significantly earlier. Stone tools on emerged coral reefs at the Huon Peninsula in Papua New Guinea have been dated to at least 40,000 years ago.7 And in Australia, although most evidence points to human arrival around the same time, some scientists have interpreted rapid sediment accumulations in lakes and nearshore areas as evidence for much earlier human impact on natural landscape processes.8 To cross from Southeast Asia (Sunda) to Australia–New Guinea (Sahul) would have required , even at the time of lowest sea level during the last ice age, an ocean crossing of more than 70 kilometers.9 Although there have been many explanations as to why humans crossed from Sunda to Sahul, the most parsimonious is that people living along the coast of Sunda had become so adept at interacting with the ocean 40,000 years ago that several groups at different times and from different places intentionally...