The Great Divide

was, however, as the world now knows it eventually sparked a stampede across the Atlantic, a tide that still continues to an extent and changed forever the very shape of our world, with momentous consequences, both brilliant and catastrophic. It is not always recognised, however, that Columbus’s discovery, whatever else it did, also marked the end – or the beginning of the end – of a particular phase in history, a singular set of circumstances that have only been appreciated – can only have been fully understood – in recent years, owing to discoveries in several fields of learning. That unique period in history had begun, very roughly speaking, more than 16,000 years previously.
     
    T HE G REATEST N ATURAL E XPERIMENT IN H ISTORY
    Until Columbus’s landfall on San Salvador, from approximately 15000 BC , when ancient peoples first entered the Americas, until roughly AD 1500, to speak in round numbers, there were two entirely separate populations on earth, one in the New World, one in the Old, each unaware of the other. This is a period of history that has never been regarded as an epoch in its own right before, but a moment’s thought will show how unusual it was, and how deserving of inquiry.
    These separate populations were faced with different environments, different weather, different landscapes, different vegetation, different animals. Nature in the two hemispheres, as we shall show, was very different. For more than sixteen thousand years – between 600 and 800 generations – these two populations, originally so similar, adapted to their environments, developing different survival strategies, different customs, different languages, different religions and, ultimately, different civilisations. For all of this time the world was divided in a unique – an unprecedented – way, but when Columbus set foot on Guanahaní, therefore, and, without knowing it, he began a process whereby this unique parallel development was eventually brought to an end.
    And this is the purpose of The Great Divide , to resurrect and recreate, to examine and investigate that parallel development, to observe the similarities and contrast the differences between the Old World populations and the New World populations, to see where the comparisons and the contrasts lead.
    In a sense the parallel development of these two populations was the greatest natural experiment the world has seen. Not a tidy experiment of course, in the laboratory sense, but a fascinating exercise in comparison nonetheless, a unique opportunity to see how nature and human nature interact, to explain ourselves to ourselves. It is a project not carried out before.
    The territories under scrutiny – entire hemispheres – are the greatest entities on Earth, along with the oceans, and some purists may be sceptical that the comparison involves too many variables to be meaningful. But I think the evidence is plentiful enough to enable us to draw some very fruitful conclusions about the important and long-term differences between the Old World and the New which explain – as well as describe – the markedly different trajectories of civilisation in the two hemispheres.
    For perfectly understandable reasons, archaeologists and anthropologists have in general looked at the similarities between different civilisations across the world, sharing the view that such comparisons will, more than anything else, reveal fundamentals about human nature, human society, and the way humankind has developed over the last 10,000 years, since the end of the Ice Age. While not denying that those parallels exist, or that they are important, this book takes the obverse approach and looks at the di ff erences between the two hemispheres, on the grounds that these are just as instructive, perhaps more so, and that they have been relatively neglected. These differences also throw an important sidelight on what, ultimately, it means to be human.
    The book is divided into three. Part One describes how the first Americans reached the New World, what was special about their journey, how their experiences distinguished them from the peoples they left behind in Eurasia. Part Two describes the important and systematic ways in which the two hemispheres differed (and differ) – in geography, climate, their flora and fauna and the interaction between these separate elements. In some ways, this is the most surprising section of the book, that something as fundamental as Nature should vary so