The composite tools, including hafted ones, were probably multi-purpose, like Swiss Army knives. A tool could have served a range of jobs. Such multiplicity of function would have served to minimize risk when living in a rapidly changing environment or when entering new and unfamiliar territory by reducing the possibility of being ill-equipped. So, overall, what technology is showing us is a parallel development of ways of dealing with a drying world in which resources were increasingly dispersed and hard to find and where travelling light was essential in order to cover large distances. This was all part of a gradual process that started with the first humans 1.8 million years ago. What technology did was to add a fits-and-starts element to the gradual process. Inventions happened when they happened, spontaneously and not gradually. Fashions spread. If new tools and weapons were useful and there was connectivity between human populations the novelties would spread quickly. Importantly, if there was connectivity with other lineages, for example the Neanderthals to the north, then the novelty could work its way geographically into these populations too (see Chapter 8). In turn, technology would have influenced the behaviour of humans by allowing them to put themselves in situations that they could not have been in previously. The resultant lifestyles in turn impacted on the evolution of human brains and bodies.
If we take a look at what was happening across different parts of southern Middle Earth during this drying after 450 thousand years ago, we find evidence of people living close to water and of movement across large distances. We also observe behaviours that have been claimed to be novel—such as the use of the coast and its resources—but which I will question in the brief review that follows. Some regions became more arid than others. Among the worst affected was North Africa which suffered from the expansion of the Sahara Desert.12 The Nubians13 lived along the banks of the Nile and the lakesides of the eastern Sahara where they butchered a range of herbivores including gazelles, rhinos, giraffes, and water buffalo. They would have been exploiting habitats close to water that included grassy, open spaces, and some trees, judging from the animals exploited. They also ventured into the mountains of the Red Sea coast where they hunted buffalo as well as elephant and kudu,14 seemingly tracking similar environments onto the higher ground where there was likely to be greater rainfall, in a similar fashion to earlier peoples in southeast Asia (Chapter 6). It seems that as conditions got drier human occupation became sporadic except in the eastern Sahara where they remained close to lakes until the onset of extreme aridity after 77 thousand years ago.
Where geography brought together very different worlds, humans made the most of the diversity. At Haua Fteah in present-day Libya, they went inland in search of gazelles and wild cattle in open areas with trees but they also entered drier, rockier areas where they hunted Barbary sheep.15 The exploitation of gazelles and Barbary sheep seems to have alternated with availability, the former in wetter conditions and the latter during drier moments, showing the adaptability of humans to aridity in these extreme situations close to the Sahara. This adaptability is also reflected in the exploitation of coastal shellfish, taking advantage of the site’s location.16 At Taforalt in Morocco, humans collected shells from the coast which was 40 kilometres away and at Oued Djebanna in Algeria a shell must have travelled a distance of 200 kilometres.17 These observations are important, not because they might represent the sudden arrival of modern human behav-iour,18 but because they hint at the degree to which humans had been able to extend their mobility by 82 thousand years ago. These North Africans may have had large annual home ranges that included coastal and inland areas or they may have established trading networks with neighbouring groups, or both.
The perception that humans suddenly discovered the coast around 170 to 160 thousand years ago19 stems from the idea that the exploitation of coastal sites in South Africa at this time was a major event that marked humanity’s arrival on the scene and its subsequent global expansion along coastal routes. The coast was probably exploited from very early times by people and certainly by 800 thousand years ago, judging from the south-east Asian evidence which I discussed in Chapter 5. In Chapter 8 we will find the Neanderthals on the coast too. So there is no big deal about finding humans living on the coast. We simply find more evidence of it after 125 thousand years ago because the sea-level rise during the global warming event around that time washed away much of the earlier evidence of coastal habitation. Pinnacle Point in South Africa, the site with the earliest claimed date, was exceptional because the lie of the land (steep cliffs) protected it from that particular sea-level rise. The evidence of earlier coastal exploitation, if it exists, must be sought in the seabed.
What the South African sites do show is that humans regularly lived in caves, probably using these for shelter as the climate became cooler. We have seen how the use of rocky habitats was a feature of some human populations from the outset and it is possible that such places were visited more frequently as the climate became colder and more arid. Rocky places would have been substitutes for trees where these were disappearing because of drought. Here people could have hidden to ambush Barbary sheep and ibexes, just as they ambushed gazelles in open woodland. By the sea they would have ambushed breeding seals and seabirds and collected shellfish typical of rocky coasts.20 In the absence of trees, rocky areas would have provided places in which to sleep at night safe from predators, especially with entrances protected by fire. Away from the tropics, such as in North and South Africa where the effects of the cold would have been most felt, caves would have provided additional incentives.
The South African sites also show a connection with fresh water, being located on or close to coastal estuaries which would have had the added benefit of a rich resource base. Coastal sites, away from estuaries and deltas, were probably also sought-after as places where fresh water could be found. Many areas of the continental shelf, now submerged, would have offered coastal oases21 to humans. These would have been places where rainwater percolated from higher ground and surfaced. During cold periods, when sea level dropped, the removal of the pressure of the sea above these springs permitted fresh water to surface with greater force and in greater quantities, creating chains of coastal oases along the emerged coastal shelf.
In Aduma in Ethiopia, humans were producing even smaller tools than before, presumably in response to further aridity, and there is evidence of long-distance transport.22 The situation resembles that in North Africa and humans here used a variety of habitats, some of which were close to, and others away from, a river. This would seem to suggest that humans were each time venturing over greater distances across arid landscapes. Food, like water, was obtained close to the river, judging from the presence of hippos, crocodiles, and large catfish at this site. Water remained a magnet which tells us that, like in the eastern Saharan lakes, human populations were tied to surviving water bodies in times of extreme drought and that mobility had helped but had not granted them independence. The Mumbwa Caves in central Africa were abandoned when dry conditions set in and the area surrounding them was less attractive to animals which relied on seasonal standing water and which were hunted by people.23 This example shows that, when conditions were really bad, people faced death or rapid emigration.
The period between 450 and 70 thousand years ago—the latter marking the onset of the latest and most intense glaciation—was one in which continental Africa experienced severe climatic fluctuations and, importantly, drought. The changes were expressed not just in the distribution and abundance of supplies of water, but also in the further opening-up of the vegetation and the expansion of treeless environments: grasslands, steppe, and desert. The human populations of southern Middle Earth suffered heavy losses. We see that at the local scale in the abandonment of sites and concentration of populations close to the remaining water bodies; we see it at continental scale through genetic bottlenecks that brought numbers down to a few thousand.
These huge pressures fine-tuned the survivors in the direction of large brains a
nd lightweight bodies capable of covering lots of ground quickly in search of water. These human populations became the ultimate rain chasers. The trend towards economical movement and transport went beyond the purely biological and into the realm of technology and culture. People made increasingly light, economical, and recyclable weapons and tools. The solution that just, and only just, allowed humans to survive in southern Middle Earth, in an uncertain world with highly dispersed critical resources, was mobility and risk reduction. Let us now turn to Eurasia and see the response there of Homo sapiens to a different set of conditions.
8
The Exceptional World of the Neanderthal
400–30 THOUSAND YEARS AGO
As Homo sapiens sapiens—the lineage of southern Middle Earth—was starting to feel the pinch after 450 thousand years ago, a separate lineage had embarked on its own particular adventure in the non-tropical regions of Eurasia. That lineage had a common ancestor with sapiens, which genetic work has put at around 400 thousand years ago.1 This Eurasian lineage is often referred to as Homo heidelbergensis, the same name that is applied to the African lineage of Homo sapiens from the same period and which was the subject of Chapter 7. Others, as mentioned earlier, distinguish the African and Eurasian lineages, giving the name rhodesiensis to the Africans and retaining heidelbergensis for the Eurasian contingent. The nomenclature has clouded the continuous evolutionary process. At one end of the scale some authors have tried to make each regional version of heidelbergensis into a species in its own right and at the other end they have merged them into one. When considering fossils that show some characteristics typical of the Neanderthals, some authors refer to these as heidelbergensis while others talk of pre-Neanderthals, a term that reminds me of ‘archaic modern human’ and reveals the inadequacy of trying to put a continuous evolutionary process in a straitjacket. Since this lineage led to the Neanderthals but was derived from the common sapiens ancestor, I shall refer to it as Homo sapiens neanderthalensis. For our purposes they are the Neanderthals, even if the earliest ones do not have all the features that have been defined as characteristic of them.
The Neanderthals lived across Eurasia but we cannot determine where they originated with exactitude, although the common but unsupported view is that it was in western Europe.2 At the height of their success, their range extended from the Iberian Peninsula in the west right across to central Siberia, and probably beyond, in the east.3 The achievement of the Neanderthals should not be underestimated and it matches that of humans in the drying world of southern Middle Earth. In Chapter 6 we saw how humans had struggled to survive on the northern edge of their range, in Europe, central Asia, and China. Occupation of northern territories was not permanent and populations were pegged back during cold periods. If that was bad, imagine what followed after 450 thousand years ago. The conditions that brought severe drought to Africa also brought extreme cold to Eurasia.
The Neanderthals, like their predecessors, could only survive in warm and humid refuges each time that the ice set off on a southerly excursion. The coastal south-westernmost tip of the Iberian Peninsula between Gibraltar and Lisbon, the mildest and least arid part of Europe, was their main stronghold. The limit of their geographical range was marked in the south by the Mediterranean Sea and its high mountains. High mountains ran from there across Middle Earth, all the way to China. They were formidable barriers which were impenetrable at the best of times, let alone during a glaciation when ice descended from the lofty heights. Each time this happened the Neanderthals were trapped between frozen northern latitudes and icy southern mountains but they picked themselves up during warm interglacials and spread northwards and upwards once more, only to be pushed back once again with the next climatic downturn.
A little while back I decided to take a look at the geographical distribution of the Neanderthals during the last time that their range contracted.4 It was significant because the Neanderthals would never recover from it. I looked at the period between 50 and 30 thousand years ago, the last known Neanderthals having survived to around 31.5 thousand years ago at Gorham’s Cave in Gibraltar.5 Using a range of criteria of suitability of different regions to the Neanderthals I predicted the extinction date for regions of Europe and the Middle East and found that the predicted last survival dates matched closely actual published dates. The results showed that the process of population extinction had been long drawn out rather than a rapid event. This contrasted with the view that around 40 thousand years ago the rapid arrival of modern humans into Europe had generated a kind of blitzkrieg on the Neanderthals with a rapid extinction across Europe.6
I found that the pattern of extinction across Europe and the Middle East had not been uniform. The most continental areas were the earliest to lose the Neanderthals and this happened quite soon. Curiously, the first populations to go were not those from the coldest, northernmost areas but those from cold and arid regions. The earliest regional extinction occurred in the Balkan Mountains and the Carpathian Basin between 47 and 46 thousand years ago followed by the Middle East around 45 thousand years ago. In spite of being on the Mediterranean and having had an important Neanderthal population,7 the Middle East was among the first areas to lose the Neanderthals and I attribute this to the repeated encroachment of desert into the region. Aridity—water shortage—would have been responsible for the Neanderthal extinction in the Middle East.
The negative effect of continental climate is seen clearly in the next two areas to lose Neanderthals—parts of Turkey and northern Europe between 44 and 43 thousand years ago; Turkey is much further south than northern Europe but it is also well east and has a very continental climate. Between 42.5 and 40 thousand years ago, huge areas of Italy, remaining areas of Turkey, the Aegean, Mediterranean France, and inland northern Iberia lost the Neanderthals. The first region of Iberia to be depopulated was the harsh northern interior which has the most continental climatic regime of the Iberian Peninsula.8 The Neanderthals disappeared from there and the remaining continental areas of the Mediterranean. This means that we should not expect late Neanderthal populations, more recent than 40 thousand years ago, across much of continental Europe or even inland Iberia.9
The regions that one would expect to have retained Neanderthals past the threshold of 40 thousand years ago would be parts of Iberia, the coastal areas of the Black Sea, and the Atlantic coast of Europe, and this proves to have been the case. This shows well how coastal areas were the most favourable for the Neanderthals. It would have been in these areas that the effects of continentality and aridity would have been minimized. The Neanderthal populations in north-western Iberia and south-western France were among the last, between 36.5 and 35 thousand years ago, leaving the southern Iberian populations as the last with the south-west being the last stronghold, with Neanderthals surviving there to between 31 and 30 thousand years ago. I then looked at a number of features in each region to see what factors had been the most important to Neanderthal survival.
The three main ones were proximity to the Atlantic Ocean, to a coastline, and to other important regions. Proximity to the Atlantic Ocean was important because it was here that the most humid, least continental climates were found. The importance of this oceanic influence in the south-west of the Iberian Peninsula became clear when we looked at the climate of the whole of the south of the Iberian Peninsula.10 The present-day climate for the entire area was mapped using GIS.11 Next we redrew the maps by introducing incremental falls in temperature and rainfall to simulate conditions in the region during a cold and dry glacial. The maps gave us a lot of information. The south-western extreme, which includes Gibraltar, is the mildest and wettest today. The town of Grazalema, just 70 kilometres north of Gorham’s Cave in Gibraltar, has the highest annual rainfall of the entire Iberian Peninsula that averages close to 2,000 millimetres. The reason for this phenomenon is that the area is the first to receive the Atlantic storms in between autumn and spring and these discharge their rain on the first high ground that they hit. T
his water then flows towards the Atlantic Ocean and the Strait of Gibraltar, irrigating drier lowland areas along the way.
What startled us was that, when we simulated a cold and dry period, this south-western corner remained mild and wet, in contrast with higher ground and areas to the east which became veritable cold deserts. When we plotted Neanderthal sites onto these maps we could see how they clustered around the major rivers and the coast and the majority of sites were precisely in the south-west. We realized why the south-western corner of Iberia, with its southerly latitude and proximity to the Atlantic had been the last Neanderthal stronghold: water had been the key factor. This revealing information showed that the Neanderthals had also been limited, like sapiens in Africa, by water availability, and why areas well north, such as Atlantic France and Britain, had remained occupied later than continental European, including central and eastern Mediterranean, regions. They were wetter. I will return to this point later in this chapter as it is crucial to understanding the Neanderthals and their survival.
Proximity to coastlines was the second ingredient of the three-part cocktail that I had come up with to explain Neanderthal survival. Coastlines were clearly influential as climate buffers as well as potential sources of fresh water (recall the coastal oases discussed in Chapter 7) and a rich array of foods. I am very conscious of the effect the coast has on microclimate: I live in Gibraltar right on the coast of the former Neanderthal stronghold. Here, summer temperatures, though hot, are much cooler than in the interior and winter temperatures are milder. It never snows in Gibraltar but you can regularly see snow in the mountains nearby. But to see the continental effect I do not need to travel up. Let me give you an example. During the winter of 2012–13, as I was writing this book, I carried out some fieldwork in an inland, low-lying area not far from Gibraltar. In the car I would get there in 40 minutes. A typical January excursion would see me leaving my house an hour before sunrise with the temperature around 12 oC. By the time I got to my study site I had seen frost, my car was warning me of ice on the road, and the temperature would range between –2 oC and +3 oC. By the time I was ready to leave for home, around 4 p.m., the temperature in the study site had risen to 19 oCor 20 oC, similar to what I found on my return home. So, in a single day, the temperature range at home on the coast had been around 8 oC while at my inland study site (at a similar altitude above sea level) the range would have been anything up to 22 oC. In midsummer, my visits to this site have been as brief as possible as the midday temperature always surpassed 40 oC, while it was unusual for it to go beyond 30 oCat home. Life has always been easier on the coast than inland.
The Improbable Primate Page 10