However, other archaeological sites in the area give us an insight into how life was changing for the hunter-gatherer societies of the Levant. Archaeologists now see the Neolithic as emerging in stages: first, hunter-gatherers became more settled, with more complex social structures; then plant cultivation appeared, and then we see the appearance of large villages and intensive food production.3 So it appears that social change came first – followed by agriculture. Göbekli Tepe fits into the early stage of this transition, as a pre-agricultural, pre-pottery site, demonstrating the existence of a complex society. For Klaus, the social changes may have been the impetus for the development of farming – perhaps to provide feasts to honour the gods. ‘For them it would have been a logical step, to manage Nature and get more food for themselves,’ he said. ‘Religion created the pressure to invent agriculture.
‘It’s very clear we must change our ideas,’ he continued. ‘Hunter-gatherers don’t usually work in the way we understand work.’ But, from the scale of construction at Göbekli Tepe, it was clear that people here had jobs: specific things to do which weren’t immediately about obtaining food, water or shelter, but were nevertheless important to society.
‘They started to work in quarries. They started to have engineers to work out how to transport and erect the stones. There were specialists in stone-working, whose job was to produce sculptures and pillars from stone,’ said Klaus. It appeared that the society that produced Göbekli Tepe could support both a workforce and professional artists.
Klaus also believed that the transition to agriculture might have led to the abandonment of Göbekli Tepe and its gods. His team of archaeologists were digging down through rubble that appeared to have been deliberately piled on top of the stone circles to cover them up. So, social changes may have driven the development of farming, but subsequent changes in society, and the emergence of new religions, had then been disastrous for Göbekli Tepe.
‘The hunter-gatherer societies were on the threshold of inventing a new way of life, of becoming farming communities. And by the ninth millennium bc this process was successful and this new way of life was developing in this region. The old spiritual world of the hunters was without any use, and so this site was abandoned. This world was completely forgotten, completely lost, never repeated.’
I found this story, of the rise and fall of the old hunter-gatherer gods, very compelling. But in fact it is very difficult to rule out farming entirely at Göbekli Tepe, as the earliest farmers would have been planting wild foods. It’s also very difficult to pinpoint that transition from collecting wild-growing plants to intentional planting. And, of course, the first planted crops would have been wild varieties: domesticated varieties would have emerged later as farmers selected particular characteristics. For hunter-gatherers for whom wild varieties of cereals and legumes were already staple foods, it may only have been a short step from gathering them to intentional planting and cultivation.4 Klaus thought that feasting, or at least the formation of more settled communities, may have prompted this step, but there may also have been climatic reasons for the adoption of agriculture. Around 14,600 years ago, and again around 11,600 years ago, there was a period of increased temperature and rainfall, each lasting only one or two decades. During each of these warm, wet phases, cereals and legumes would have flourished – providing humans with plenty of easily exploitable resources.3 Between these two wet, warm periods was the cold, dry snap of the Younger Dryas. The effects of this may have been over-emphasised, but for people getting used to living on plentiful cereals and legumes, a period of worsening climate may have encouraged them to start cultivating crops. This climate explanation echoes what I had discovered from reading about the origins of agriculture in China, and I find it very persuasive. Because, at almost exactly the same time, on opposite sides of the globe, people were inventing agriculture. It may not be such a coincidence: both populations were living in environments affected by global climate change.
The date of Göbekli Tepe places it slightly earlier than other archaeological sites where the transition to agriculture is clearly documented. It now seems clear that this area, between the upper reaches of the Tigris and Euphrates, was indeed the place where farming got started in the West.5 Early farming communities – still without pottery – became established in Turkey and northern Syria between about 11,600 and 10,500 years ago.4 At these very early sites, archaeologists have found burnt remains of wild cereals (like einkorn wheat, rye and barley) and legumes (peas, vetch and lentils). Slightly later, from around 9500 years ago (7500 bc), evidence of domesticates such as emmer wheat and barley appears – sometimes in higher (more recent) layers at the same sites.5 Later still, herd animals are domesticated.3 People whose recent ancestors had hunted wild animals in the foothills of the Taurus and Zagros Mountains started corralling, tending and breeding them. Along with plant and animal domestication came a new toolkit, with sickle-knives for cutting and querns for grinding cereals.5
Botanical and genetic studies also point to this area as the ‘cradle of agriculture’. Wild varieties of the important Neolithic crops (einkorn and emmer wheat, barley, lentil, pea, bitter vetch, chickpea and flax) are found growing together in this area. The limited genetic variability of domesticated crops also lends support to the idea of a single, core area of plant domestication.5
Once agriculture began, it allowed populations to expand further. Food resources became more reliable. People settled down and large villages started to appear. It all sounds wonderful – until you take a closer look at what was happening to the health of individual people. Because, although much of the risk of inadequate food supply may have been shed by growing crops and keeping domesticated animals, the quality and range of the farmers’ diets was not particularly good. Archaeologists have long supposed that the transition to agriculture was positive in all sorts of ways, bringing better health and nutrition, increased longevity, and more leisure time. But the truth is a little harder to bear and somewhat counter-intuitive. From the study of human skeletons from this crucial period of changeover, biological anthropologists have found that the switch from foraging to farming brought with it a general decline in health.
Compared with hunter-gatherers, farmers had more tooth loss and more dental caries, had restricted growth and shorter stature, and reduced life expectancy. Skeletal evidence of trauma becomes more common, indicating an increase in violence and conflict. Neolithic people also suffered more from infectious diseases than previous groups, probably because of the combined effects of a poor diet and more crowded living conditions. Anaemia was also more common.6,7 Traditionally, archaeologists have argued that the Neolithic brought with it improved health and reduced mortality, and so populations could expand rapidly, but the bones of our ancestors show us that this was not the case at all. The dawn of agriculture and permanent settlement brought about worse health and reduced life expectancy. But in spite of all these disadvantages for individuals, agriculture brought with it an increased birth rate that outstripped the reduced life expectancy – so the populations expanded.6,8 It is difficult to work out the sizes of past populations, but researchers seem to agree that population growth was extremely slow during the Palaeolithic, and that at 10,000 years the world contained around eight million humans. By ad 1800, the global population was a stonking thousand million people.8
Agriculture then spread out of the Levant: into central Anatolia by 8000 to 9000 years ago, then eastwards into the Zagros foothills and Indus Valley, and westwards, along the Danube and along the Mediterranean coast.4 By 7500 years ago the first farmers appeared in Hungary, and by around 6000 years ago the culture had spread all the way to northern Spain, where the Neolithic seemed to have been adopted as a ‘package’: evidence of domesticated crops and livestock, pottery and megalithic monuments suddenly appears in the archaeological record.9 So, the spread of agriculture into Europe, between 10,000 and 6000 years ago, followed similar routes to the original, Upper Palaeolithic colonisation of Eur
ope.4 But was this a movement of people (demic diffusion) or ideas (cultural diffusion) – or both?
When I started considering this question I thought that genetic studies might provide the answer. But in fact, over the years, various studies have turned up somewhat conflicting results. Y chromosome studies have revealed what appears to be a cluster of lineages spreading from the Levant across Europe: in other words, a movement of people.10,11 Some analyses of mtDNA data have also uncovered a potential Neolithic contribution to the European population,12 but others have produced very little evidence for demic diffusion. Extraction of ancient DNA from some Neolithic skeletons from central Europe revealed that a quarter of them had a type of mtDNA that is now extremely rare in Europe, suggesting that the genetic contribution to the European gene pool from Neolithic incomers was probably minor, at least within maternal lineages.13 The discrepancy between the maternal mtDNA and paternal Y chromosome patterns has been explained by some as indicating a spread of male farmers out from the Near East, intermarrying with indigenous women. Other researchers have suggested that the contradictory results actually warn us against coming up with too simple a model. The spread of farming across Europe would have been a complicated matter, with the degree of demic and cultural diffusion varying in different regions.10 Broadly speaking, it seems that there was a movement of some people out of the Near East in the Neolithic, but these people mingled with the ancient populations already established in western Europe, rather than replacing them. At the moment, the picture is far from clear, but, as more work is done and more samples collected, particularly from ancient skeletons, the way that the Neolithic made its mark on Europe should become clearer.
The beginning of food production was a revolutionary event in prehistory. It paved the way for large-scale settlement – for civilisation. After hundreds of thousands of years of being nomadic hunter-gatherers, humans began to settle down and farm. It seems like a long time ago, but set against the scale of human prehistory it’s a relatively recent development.
Göbekli Tepe had lain hidden under rocky fields at the top of a hill for 12,000 years, but when the ancient gods had been rediscovered they held their discoverer firmly in their grasp. When Klaus found the place, he was exhilarated, but he also knew at that moment that he had two options: either to walk away right there and then, or to spend the rest of his life there, excavating this remote hill where human society had started to change.
‘I was very excited. But it was clear from the first minute that I had a choice, too: to turn back and not tell anyone about this discovery, and never come back … or to stay and work here for the rest of my life.
‘It is a dream,’ he said, ‘but it is also difficult to have such a site. You are captured by it. You belong to it.’
I left Göbekli Tepe very sure that I would hear more about this amazing place in the future. But, for now, my journey would take me to the lands of my final destination, to the Americas, the last continents to be reached by humans.
5. The New World:
Finding the First Americans
Bridging the Continents: Beringia
This vast continent was the last of all the great landmasses to be populated by humans. For hundreds of thousands of years, while humans spread throughout Africa, Asia and Europe, the New World was unknown and unreachable. Whereas modern humans replaced archaic populations – Homo erectus, Neanderthals – in the Old World, Homo sapiens would be the first human species to set foot in the Americas.
Palaeolithic archaeology in America is riddled with controversy: there is ongoing argument over the date of colonisation, the number of ancient migrations into the New World, the origin of the incoming populations and the routes they took.
Some have suggested very ancient dates of colonisation, as early as 40,000 or 50,000 years ago, but the evidence is very shaky indeed. Most researchers agree that humans did not reach the Americas until after the LGM. Until very recently, the prevailing opinion was that the first inhabitants of America were hunter-gatherers who moved down through North America about 13,500 years ago, and who carried with them a stone toolkit called ‘Clovis’, named after the site in New Mexico where Clovis stone points were found in the 1930s, associated with the remains of a dozen mammoths.1 But now, with the emergence of new archaeological sites, the redating of some previously discovered sites, as well as a growing database of genetic evidence from living Native Americans, the dates for the occupation of the Americas have been pushed back further and further.
Most archaeologists agree that the route taken into the New World was, very broadly speaking, eastwards from north-east Asia, and then down through North America and into the south.
Getting into the Americas via this northern route, during the Ice Age, required an ability to exist and subsist in extremely cold, Arctic environments. Vladimir Pitulko’s Yana site in the north-east of Siberia – the place I had arranged to visit but then been thwarted by Russian airline schedules – showed that modern humans were living far up in the Arctic from at least 30,000 years ago. Some of the elements in the Yana toolkit are similar to the Upper Palaeolithic technologies of North America, including ivory foreshafts for spears, which are also found among Clovis tools.
And, unlike today’s geography, where the two landmasses are separated by the Bering Strait, when people were living at Yana, there was a connection between Siberia and Alaska. So people could have crossed over into the Americas. This now-submerged land is sometimes referred to as the ‘Bering land-bridge’, although this term is somewhat misleading as the ‘bridge’ was about the size of Europe: a landmass in its own right. It stretched all the way from the Kolyma River in Siberia to the Mackenzie River in Canada: about 3200km wide and 1600km from north to south.2 Many archaeologists prefer to call it Beringia.
Even during continental glaciations, it seems that Beringia remained, although very cold tundra, ice-free, and there would have been plenty of herd animals roaming the grassy tundra to tempt the Siberian hunters eastwards, including woolly mammoth, horse, steppe bison and saiga antelope.3 As the Ice Age rolled on, and northern Siberia became less and less habitable, Beringia would have formed a refuge for the hunters of the north.
Looking at a map of this area as it would have been 20,000 years ago, the route across from Asia to Alaska may have been ‘open’ but the rest of North America was sealed off by a vast ice sheet. In fact, there were two great bodies of ice – that merged east of the Rockies – known to palaeoclimatologists as the Cordilleran and Laurentide ice sheets (see map on page 300).
But archaeological evidence of humans in Alaska and the Yukon dating to before the LGM is very scrappy, inconsistent – and hotly debated. The first well-dated, generally accepted evidence of modern humans in eastern Beringia – what is now central Alaska – comes from a site called Swan Point, where a collection of stone tools, including microblades and burins, has been found, similar in many ways to the Siberian lithic industries. The archaeology at Swan Point dates to around 14,000 years ago. Then there are a number of other archaeological sites in central Alaska dating to between 13,000 and 14,000 years ago.4 These dates are well after the LGM, but there are some controversial sites in the northern Yukon that may hint at a human presence there – well before the height of the last Ice Age.
Fragments of bone – which some archaeologists think are tools – have been found at Bluefish Caves and Old Crow River sites in the northern Yukon. Canadian archaeologist Richard Morlan claims that there are definite signs of human interference with these bone fragments: there is a bison rib, dating to around 40,000 years ago, bearing a cut mark that appears to indicate that it has been sliced into with a stone tool. Other, apparently butchered, bison bones have been found at sites near the Old Crow River, as well as mammoth bones that appear to have been split to access the marrow inside, then broken further to use as tools. Richard Morlan has gone as far as to call the bone fragments ‘cores and flakes’, by analogy with stone tools. Similar bone ‘tools’ and apparentl
y butchered bones have been discovered in the Bluefish Caves, to the south of Old Crow River.2 These have been dated to around 28,000 years ago.4 (There were also stone tools in these caves, but they have not been dated, and are similar to much later tools from Alaska, dating to well after the LGM.)
But other archaeologists have argued that the bones could have been broken by natural processes: through being gnawed by carnivores, trampled by large animals, being carried along and smashed up in rivers, becoming frozen and thawed, or even blown to pieces by volcanic eruptions. Even though some of the bone fragments look as though they have been deliberately flaked, most archaeologists find this evidence too flimsy. Flaked bone tools are not unique to these controversial sites in the Yukon: there are precedents for bone-flaking from a range of sites across Eurasia, including the Dyuktai culture of Siberia and in North America.2 However, the peculiar absence of any other well-stratified, well-dated evidence (stone tools, human bones, indeed anything else) from these sites means that most archaeologists view them with caution.
But these very early dates (for America) are certainly quite intriguing, and they don’t seem that unbelievable given that we know people were living in Yana, in north-east Siberia, 30,000 years ago. Those Cordilleran and Laurentide ice sheets expanded to seal off the rest of North America by about 24,000 years ago. Before that, if there really were people living in Alaska that early, they could have made their way south, down through gaps between the ice sheets.4 The archaeologists working at the Old Crow River and Bluefish Cave sites are even now uncovering and analysing evidence, so this opening of the American chapter is still very much in draft form.2
The Incredible Human Journey Page 35