Another site on the edge of Middle Earth that appears to have been occupied during mild conditions is Dmanisi in Georgia, which I referred to at the start of this chapter. The site was close to a river floodplain and had fauna which indicate open, savannah-like conditions with a range of species that included ostriches, deer, gazelles, elephants, rhinos, and horses along with jaguars, sabre-tooth cats, large hyenas, and bears. The stone tools were Oldowan.33
Further east and north-east, the earliest human presence in northern China dates to 1.66 million years ago,34 and is therefore not much younger than the other sites that we have discussed so far. The oldest known site is Majuangou in the Nihewan Basin which, not unsurprisingly given what we have learnt so far about erectus, was a lake that alternated wetland and lake margin with a familiar fauna that included rhino, horse, elephant, deer, gazelle, a large hyena, and ostrich. The stone tools were of the Oldowan type. Even earlier is the human presence in the Yuanmou Basin in south-west China, around 1.7 million years ago.35 These are the oldest humans on mainland East Asia and just younger than those on Java. Here they lived by a lake, made Oldowan tools, and lived alongside a fauna that was very similar to that in the Nihewan Basin and, indeed, many of the other sites that I have described.
When Dennell and Roebroeks36 described their Savannahstan, they put grasslands as the common denominator that linked sites from the Atlantic coasts in the west all the way across to China in the east. This is understandable as we have seen how grazing animals were a feature of most early human sites. But the common denominator for me is fresh water. It is present in all sites and offered optimal conditions. The animals might have been different in Baza and Java but the water was the same. Wetlands, lakes, and river systems would have marked the dispersal pattern of humans as successive generations occupied similar places away from the centre of origin.
The proximity of first dates across Middle Earth is such that it makes it difficult for us to discern how and from where the early human populations spread but it is clear that it must have been a rapid dispersal. It seems that Europe—the Iberian Peninsula at least—and northern China were reached last but we have little to choose between East Africa, South Africa, North Africa, India, south China, or Java. My hunch is that it started somewhere in the core of Middle Earth. The edges of Middle Earth were occupied during conditions that were milder and wetter than today. Further south, seasonal rainfall and scattered water bodies were dealt with through increased mobility and the use of a portable stone-tool technology—the Acheulian. Exceptionally, in south-east Asia, rainforest expansion cornered humans in coastal wetlands and even led to inter-island dispersal. How south-east Asian sea crossings were achieved is a mystery which leaves the door ajar to other possible crossings of water bodies, like the Strait of Gibraltar. By 1 million years ago, humans had colonized all of Middle Earth. In Chapter 6 we will take a look at what happened next, when the climate took yet another downturn.
6
The Drying World of the Middle Pleistocene
800–400 THOUSAND YEARS AGO
The oscillating warm-cold cycles that characterized the northern hemisphere from ~8oo thousand years ago are best known for the cold spikes that marked the start of the glaciations in northern Europe. These cycles were not just about temperature change. In the tropics the cycles are reflected instead by water, wet and dry periods being the dominant force of ecological change. The reality is that the climate oscillations of the Middle Pleistocene (the geological period ~780-125 thousand years ago) generated severe phases of aridity across the world, not just the tropics. These cycles introduced desertification across large areas of Middle Earth1 and they were responsible for the geographical expansion and contraction of ranges, and the extinction of many species. The important consequence in the context of our story is that aridity generated ecological barriers between different regions of Middle Earth. The result was isolation of different regional human populations.
A major step that marked a significant climate change in East Africa around 1 million years ago took the continent another step towards drying up. This was not a one-way ticket towards aridity but took, instead, the form of violent swings in climate which heightened the extremes.2 The droughts became more severe and alternated with wetter moments. African human populations in this period would have felt that their world was in turmoil. Aridification must have affected adjacent regions too, especially North and South Africa, the Middle East, Arabia, and the Indian subcontinent. The paradox is that between 1 million and 400 thousand years ago the African human populations seem to spread out and into drier and cooler environments.3 In South Africa, for example, humans with Acheulian technology had survived only in the wetter north and east prior to 1 million years ago but after this point spread into the drier interior and the western margins. How can we explain the apparent paradox?
We can do so very easily in my opinion. In Chapter 5 I suggested that the makers of the Oldowan tools had tended to occupy areas next to permanent water bodies. In other words, they lived in fairly stable environments compared to more unstable places where they would have had to move around over large distances in search of water. The Acheulian gave them portability in such circumstances. As the world dried further, those populations able to make Acheulian as well as Oldo-wan tools fared better than those who could only make Oldowan. Acheulian people were the ones that could deal with variable and arid conditions. They had got used to these conditions so that, when the climate became drier and more variable after 1 million years ago, they were able to cope and even expand into arid environments. We would then expect that, as the world became more arid the Oldowan would disappear altogether but the Acheulian would remain and that is exactly what happened: after more than 1 million years of the two technologies, the Oldowan fizzled out during the increasingly arid conditions of the Middle Pleistocene4 (Fig. 4).
FIGURE 4. How technologies can coexist, survive, and disappear. The figure shows a first scenario in which Oldowan (O) and Acheulian (A) coexist in a humid environment. The Acheulian exists only on the drier, peripheral environments where its portability allows its makers mobility in search of scattered water resources. In the second scenario, climate has become more arid and the Acheulian dominates large areas, the Oldowan becoming severely restricted.
In South Africa, the Middle Pleistocene human populations with Acheulian moved across the landscape with reference to available surface water (springs, pans, rivers) and stone outcrops where tools could be made.5 Acheulian tools were made precisely to be carried, giving some degree of independence from stone quarries, but we have no knowledge of the water-carrying technology of these people. If they were able to carry water between sites it would have been in perishable materials—ostrich eggs, wooden containers, or plants that could act as receptacles—that would be invisible in the archaeological record. Even if they did, return to known sources of water would have been regular as any supplies carried would have been limited.
Humans lived at Olorgesailie in the Kenyan Rift Valley from around 990 to around 625 thousand years ago, roughly 350 thousand years of occupation that was probably interrupted many times by depopulation. It is important to understand how coarse archaeological signals, that could be of the order of thousands of years, cannot be matched to human generation times which are on a completely different scale of time. At Olorgesailie archaeological horizons are thought to represent brief periods of around 1 thousand years6 and conclusions have been drawn about human behaviour on the basis of comparisons of different strata. There is always a risk in assuming that such long periods were homogeneous, which is extremely unlikely.
Nevertheless, Olorgesailie does give us very useful insights. The useful information is that the combination of water, trees, and open spaces is applicable throughout the long sequence. Rocky places were also a regular feature, at least as sources of raw materials with which to make tools. Whenever people were at Olorgesailie, it was in that context. It seems that sometimes conditions we
re drier and other times wetter—a lake expanded and shrank in size, streams sometimes flowed freely with ample water and other times were reduced to trickles—and the distribution of stone tools on the landscape changed. So humans may have been responding to changes in the proportion and distribution of trees, open spaces, and water. One suggestion has been that these people lived in the hills, where the raw materials for making their tools were available, and they descended to the lake with these tools in search of food and water. This would imply that humans fed directly where they caught or scavenged large mammals or, instead, took chunks of meat and large bones filled with marrow back home. That seems fine, but what about water? This interpretation gives us two options: they only drank when they were by the source of water and somehow managed to spend the rest of the time without drinking or they had containers for carrying water. Of course, we can interpret the observations in other ways. One would be that erectus went to the higher ground in search of stone and had its base either close to water or, if that was too dangerous because of the risk of predators close by, somewhere in between and close to both rocks and water. What Olorgesailie does also confirm very clearly is the mobility of people who, by this time, were introducing some stone artefacts from sources that were a minimum of 26–45 kilometres away.
Around 780 thousand years ago, a community of humans was living by a lake that was not far from Ubeidiya (Chapter 5). The site of Gesher Benot Ya’aqov, usually referred to as GBY, is in the northern part of the Dead Sea Rift, some 12 kilometres north of the Sea of Galilee. It has become emblematic for a variety of reasons, most importantly because it has the earliest evidence for the processing of plant foods and the working of wood.7 The people who lived at GBY were always close to water, sometimes a river and at other times a lake, with a landscape composed of trees and open spaces judging from the plants recovered and also the presence of the straight-tusked elephant which was apparently hunted and butchered on site.8 The archaeological site is waterlogged and this accident of Nature has preserved a large range of plant material that would otherwise have deteriorated. The range of plant materials included wood, bark, fruit, and seeds. Many were edible and a large number were plants that live immersed in or float on fresh water.9 Fifty-four stones were recovered from the site. These were pitted in ways that indicate that they had been used as hammers and anvils to crack nuts of seven different species, including two aquatic ones.10 Burnt seeds, wood, and flint found at GBY provide the evidence indicating that humans at this site had control over fire.11 The uneven pattern of distribution of burnt fragments of flint suggests that burning was localized in particular areas that could be interpreted to have been hearths. The wood of several plants—including the edible olive, wild barley, and grape—was found burnt, providing a possible link between fires and cooking.
GBY represents the earliest known control and use of fire but Richard Wrangham at Harvard University argues that it is much older and was a defining feature of the first humans.12 The evidence, Wrangham argues, comes from our anatomy. With humans of 1.8 million years ago we see a reduction in jaw size, brain enlargement, and a shortened gut. These anatomical changes were possible because humans were cooking their food, making it easier to chew and digest. Energy was extracted more efficiently from cooked food which helped to fuel a large brain. The idea is appealing, and may well be close to reality, but it will always suffer from the retort challenging the lack of direct evidence of the hearths that humans made nearly 2 million years ago. Apart from its use in cooking, fire would have served additional functions, such as keeping predators at bay at night and providing warmth, something that would have been particularly important in the cooling environment of the temperate parts of the world during the Middle Pleistocene. We should remain open to the possibility that humans controlled fire from an early stage. If they had it at GBY at 780 thousand years ago, the chances are that its use started some time before. Just how much earlier is hard to pinpoint.
Middle Pleistocene sites with the quality of preservation and depth of occupation of GBY and Olorgesailie are rare. Robin Dennell has reviewed the Asian sites13 and there is very little that can compare. A common denominator of sites across Arabia, India, China, and south-east Asia is water as most sites are close to rivers, lakes, or other wetlands. Evidence of living on the coast is harder to find but this must reflect a problem related to loss of coastal archaeological sites because of rising sea levels. Middle Pleistocene populations would have lived on the coast and exploited its rich resources, judging from the evidence from south-east Asia (Chapter 5). Europe, Asia’s westernmost peninsula, has been intensely studied since the 19th century and has a few sites that offer comparable levels of detail to GBY and Olor-gesailie. Clive Gamble’s reviews are still useful summaries of the European Middle Pleistocene picture.14 The majority of European Middle Pleistocene sites are riverside and lakeside gatherings of humans where they seem to be butchering large mammals. These mammals are typical species of European open woodland, of places that combined trees and open spaces.15 The picture across Middle Pleistocene Eurasia is one in which humans lived in places close to fresh water, with trees and open spaces, and sometimes in rocky areas where they seem to have started the habit of entering and living in caves, even if only sporadically.
The pattern of human occupation of Eurasia was heavily dependent on rainfall, temperature, and—in northern latitudes—also day length. In Chapter 5 we established that the first confirmed human presence in western Europe was in the Iberian Peninsula around 1.4 million years ago. We do not know if that date marked the establishment of a permanent human presence in Europe or if, instead, European populations repeatedly went extinct locally and were replenished by later immigrants. It would take them another half-a-million years to reach higher latitudes in Europe. The earliest recorded presence in north-western Europe is around 700 thousand years ago, at Pakefield in Suffolk which is at 52°N.16 Curiously, this date is after the first known use of controlled fire by humans which poses the intriguing question whether fire was the key to the expansion to higher latitudes at a time when the world was getting cooler and in areas where long winter nights would have curtailed activities normally carried out in daylight. Having said this, the presence of people at 52oN coincided with an interglacial, a warm period sandwiched between colder episodes. This trend, of a presence in the north only during warm periods, seems to be prevalent across Middle Pleistocene central and northern Europe, borne out by the long periods when Britain was deserted.17
The human presence along the northern fringes of Middle Earth, not just on the European peninsula, during the Middle Pleistocene was limited to warm periods between glacials.18 Central Asia was abandoned during cold and dry periods and the growing central Asian deserts became a significant barrier. China, especially the north, seems to have been occupied only during interglacials and interstadials. A similar trend is observed along the higher ground, in the mountains of Middle Earth that replicated the effects of latitude across short vertical distances. Caves were occupied sporadically in the Caucasus and the central Asian mountains. One of the better known sites is the huge cave of Sel’ungur in Kyrgyzstan which is situated at 2,000 metres above sea level and was occupied by people who left the cave during cold periods. When living in this cave they had a panoramic vista outside that included mountain steppe, desert, areas with trees and shrubs by ephemeral streams within wet depressions.19 It seems that the combination trees/open-spaces/water, here combined with rocky habitats, also worked for humans high up in the mountains of central Asia.
In the southern part of Middle Earth, in North Africa, Arabia, India, and south-east Asia, day length and temperature would not have had the impact that they had in the higher latitudes. Here it was shortages of rainfall that caused havoc. At Hunsgi-Baichbal in southern India,20 humans lived close to rivers and streams during the wet monsoon but aggregated around shrinking water sources in the dry season. Then they seem to have hunted medium to large game that was attracted
to the few remaining water sources. In the wet season groups were more widely dispersed across the landscape, when many smaller streams carried water. Humans then had a wider range of resources available that included many edible plants and small game. In the Arabian Peninsula, today engulfed by the desert, Acheulian sites were associated with a range of environments, including coastal zones, high ground, and interior plains, occurring along river terraces and near lake shores.21 This occupation of Arabia would have happened during wet cycles when desert gave way to steppe, grassland, and savannah.
An intriguing possibility, and a complete contrast to India or Arabia, has been offered as a response of people to drying conditions in the humid tropical contexts of south-east Asia. Panxian Dadong in south-east China is situated at 1,630 metres above sea level. Here humans lived among pandas, on a valley floor at the confluence of three rivers in a landscape of mixed woodland, bamboo forest, and open rocky areas. It seems that humans colonized these uplands during cold and dry periods when water shortages forced populations to move to higher ground, which was wetter.22 Cooler conditions would not have had the impact in the tropics that they had in higher latitudes so moving up mountains would not have been restricted by temperature.
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