Palaeolithic voyage for invisible islands beyond the horizon

Yousuke Kaifu,Yoshimi Kubota,Tien-Hsia Kuo,Sen Jan

doi:10.1038/s41598-020-76831-7

Yousuke Kaifu, Yoshimi Kubota + Show 2 more

Open Access

https://doi.org/10.1038/s41598-020-76831-7

Copy DOI

Abstract

How Palaeolithic maritime transportation originated and developed is one of the key questions to understand the world-wide dispersal of modern humans that began 70,000–50,000 years ago. However, although the earliest evidence of maritime migration to Sahul (Australia and New Guinea) has been intensively studied, succeeding development of Paleolithic maritime activity is poorly understood. Here, we show evidence of deliberate crossing of challenging ocean that occurred 35,000–30,000 years ago in another region of the western Pacific, the Ryukyu Islands of southwestern Japan. Our analysis of satellite-tracked buoys drifting in the actual ocean demonstrated that accidental drift does not explain maritime migration to this 1200 km-long chain of islands, where the local ocean flows have kept the same since the late Pleistocene. Migration to the Ryukyus is difficult because it requires navigation across one of the world’s strongest current, the Kuroshio, toward an island that lay invisible beyond the horizon. This suggests that the Palaeolithic island colonization occurred in a wide area of the western Pacific was a result of human’s active and continued exploration, backed up by technological advancement.

Highlights

How Palaeolithic maritime transportation originated and developed is one of the key questions to understand the world-wide dispersal of modern humans that began 70,000–50,000 years ago
Because the drift hypothesis for the Ryukyu Islands cannot apply to the northern migration routes that requires drifting against the Kuroshio, we focus on the southern migration route, where the ocean flow pattern is relatively simple and has been stable at least since the Last Interglacial Period
The situation must have been similar in the late Pleistocene, because the flow path of the Kuroshio has been unchanged in this region since

Summary

Introduction

How Palaeolithic maritime transportation originated and developed is one of the key questions to understand the world-wide dispersal of modern humans that began 70,000–50,000 years ago. We show evidence of deliberate crossing of challenging ocean that occurred 35,000– 30,000 years ago in another region of the western Pacific, the Ryukyu Islands of southwestern Japan. Migration to the Ryukyus is difficult because it requires navigation across one of the world’s strongest current, the Kuroshio, toward an island that lay invisible beyond the horizon This suggests that the Palaeolithic island colonization occurred in a wide area of the western Pacific was a result of human’s active and continued exploration, backed up by technological advancement. Maritime migration to Sahul (a combined continent of Australia and New Guinea), which occurred about 47,000 years ago or earlier, is the oldest accepted evidence for open ocean crossings by modern humans[1,2,3,4,5], and has been central to such discussion. The accuracy of the ocean model used is often ambiguous; the grid size may be too large to reflect complicated and hourly changing ocean flows; other factors influencing a floating object such as wind waves and swells are not considered

Methods

Results

Conclusion