Having survived glacial cycles in Eurasia since around 600,000 years ago, the Neanderthal line was about to enter its final stage. This coincided with the arrival of the next wave of Homo sapiens. In Chapter Six we attempt to answer the question why events this time unfolded quite differently from the first Asian arrival, some 130,000 years ago. We will also take a close look at the classic Neanderthals and their ways of life, for it is in their final stage of existence that the Neanderthals became most distinct from their African cousins and took on the form that most people associate with this fascinating human species.
CHAPTER six
Endgame:
60,000 to 25,000 years ago
If the Neanderthal story were a movie, this would be the dramatic final act. It had incredible twists and turns – wild swings in temperature, extinctions of large European mammals and the intrusion of a rival human species into their homeland. It is the period for which we have by far the most evidence of their way of life, and yet it is a time that remains full of mystery.
This period falls into three distinct phases. The phase of the ‘classic Neanderthals’ began 60,000 years ago when the Earth’s climate entered a mild yet highly variable interglacial, which had nothing like the kind of warmth and stability that characterized the Eemian or the current Holocene. The Neanderthals took advantage of these conditions to increase their range within Europe, where they repopulated the northern areas, and they continued to spread eastwards into Asia.
The second phase was one of overlap with Homo sapiens, and it started some 45,000 years ago when our species arrived in Europe. This phase, which has long been the subject of both literary and archaeological speculation, has in recent years come into better focus. A key problem with this period is that it takes place right at the horizon of effective carbon dating. A number of recent scientific advances – improvements in dating technology, the generation of fine-resolution data of past climate and the introduction of computer modelling – have shed new light on one of the most pivotal moments in human evolution. Perhaps the greatest surprise to come out of this new research is that modern humans did not initially have much of an advantage over the Neanderthals.
Map showing major Neanderthal and modern human sites discussed in this chapter. The Danube River provided the first Homo sapiens to reach Europe with a route from the edge of the Black Sea to Germany and on to resource-rich southern France.
The final phase, both of this chapter and of the Neanderthal line, starts around 37,000 years ago. At this time the modern human presence in Europe underwent a dramatic change. An archaeological culture called the Gravettian, probably representing an influx of new people, appeared, and was more successful than both the Neanderthals and the earlier wave of Homo sapiens that had been in Europe for nearly 10,000 years.
By the time of the spread of the Gravettian culture through Europe, the Neanderthals were extinct. After hundreds of thousands of years as the masters of Europe, our human cousins were gone. All they left behind were the less perishable traces of their existence, their stone tools, hearths, food debris and of course their bones, which we would later use to date their extinction and to extract their DNA in the hope of settling the lingering question of whether we replaced them or interbred with them. Are they completely gone, or does a little Neanderthal live on in us?
To put these events in perspective, it is helpful to imagine the entire course of human evolution, from the appearance of the first Homo habilis in Africa to the present, as taking place over the course of a single day. For convenience, let us start the clock with midnight representing 2.4 million years ago, which is within the range of when the genus Homo is thought to have emerged. In this time-compressed day, with each hour representing 100,000 years, humans left Africa at dawn, around 5 to 6 am. They first arrived in Europe at noon, already at the halfway point since the appearance of the human line. In what was probably a subsequent out-of-Africa expansion, Homo heidelbergensis spread from Africa to Europe at dusk, just before 6 pm. By 9 pm the Neanderthals had evolved in Europe and were manufacturing Levallois tools, while their counterparts in Africa were making similar technological advances.
At around 10.45 pm an early form of Homo sapiens arrived in the Middle East. By 11.20 pm Neanderthals had become the predominant type of human in western Asia and were steadily pushing eastwards towards Siberia, which they reached around 11.30 pm. By 11.40 pm, just twenty minutes before the present, all traces of the Neanderthals were gone. When the Last Glacial period ended at 11.54 pm, modern humans were on the verge of establishing long-term settlements and inventing agriculture.
In this chapter we will run through the principal suspects in the mystery of the Neanderthals’ extinction. Were their bodies maladapted to a changing planet? Was their diet unsustainable or did it leave them vulnerable to competition? Did they live in too restricted a range of environments? Was their cultural life somehow deficient, indicating critical cognitive shortcomings? What was the impact of the arrival of Homo sapiens?
The skeleton of a Neanderthal found in Kebara Cave, Israel. Dating to around 60,000 years ago, it provides key evidence that Neanderthals sometimes buried their dead.
Reconstruction of a Neanderthal butchering a deer, based on remains found at Shanidar Cave, Iraq.
Top and Above
Examples of early symbolic behaviour by modern humans: a red ochre ‘plaque’ with cross-hatches from Blombos Cave, South Africa, dating to around 100,000 years ago, and hand stencils at El Castillo, Spain, dating to more than 40,000 years ago.
Reconstruction of a Neanderthal based on a skeleton from La Chapelle-aux-Saints, France.
Neanderthal skull and long bones from Saint-Césaire, France. The discovery of this ‘classic’ Neanderthal dating from just 36,000 years ago helped to demonstrate that modern humans and Neanderthals represented separately evolving lines rather than sequential stages in our own evolution.
Neanderthal skull and parts of a skeleton found in 1908 at La Chapelle-aux-Saints, France. The individual suffered from arthritis and bone degeneration, which led to early reconstructions of Neanderthals with a stooping posture (see p. 183).
Archaeologists excavating in El Sidrón Cave, Spain, which was discovered in 1994 and contained the remains of twelve Neanderthals, from which Neanderthal DNA has been extracted.
Svante Pääbo of the Max Planck Institute, Leipzig, Germany, a pioneer in the field of palaeogenetics and the driving force behind the discovery of Neanderthal DNA.
Antonio Rosas at El Sidrón Cave, where he leads the analysis of the most complete collection of Neanderthal remains yet found in Spain.
The Neanderthal Museum in Germany used prosthetics and make-up for this ‘Stone Age Clooney’ in order to re-examine the question of whether Neanderthals, if they dressed like us, would be able to walk among us without undue attention.
A group of Neanderthals from the film The Clan of the Cave Bear, made in 1986 and based on the bestselling novel by Jean M. Auel.
As we examine these possible causes of their demise, we develop a new understanding of the Neanderthals. It is an unfortunate truth that extreme stress can be the best test of character. In learning about the character of the Neanderthals, who did not make it through these tough times, we also learn something about our ancestors who did.
The classic Neanderthals
As we discussed in Chapter One, the first bones formally identified as Neanderthals were the ones that emerged from the Feldhofer Cave in the Neander Valley in 1856. The confirmation that this represented a separate and unique population, or species (as opposed to a deformed individual), came from subsequent discoveries of a pair of skeletons at Spy, Belgium, eight individuals at La Ferrassie, France, and a nearly complete skeleton at La Chapelle-aux-Saints, France. All of these Neanderthal individuals have been dated to between 70,000 years ago (the upper limit of the La Ferrassie dates) and 40,000 years ago (Spy and Saint-Césaire).
More recently, other nearly complete Neanderthal skele
tons have been unearthed and dated to this same date range. The archaeologist Paul Pettitt compiled a list of Neanderthal skeletons that show some degree of intentional burial, and this list nicely illustrates just how rich the archaeological record is for the ‘classic’ Neanderthal period, in contrast to earlier times, when we were only able to discuss a handful of sites. From France, there is one individual from La Quina, two from Le Moustier, one from Roc de Marsal and one from Saint-Césaire (probably the most important one of the group for reasons we discuss below). In Syria, two children have been uncovered at Dederiyeh Cave. In Crimea, two Neanderthals are from Kiik-Koba and a further three are from Zaskalnaya. In Russia, in the foothills of the Caucasus Mountains, a Neanderthal infant was excavated at Mezmaiskaya Cave.
We should add to this list two sites where the Neanderthal bones show signs of having been cannibalized: El Sidrón, Spain, was discovered in 1994 and contained remains of some twelve Neanderthals, and Vindija Cave, Croatia, has several layers of deposits and was excavated extensively in both the early and late 20th century. These two sites have been key sources for extracting Neanderthal DNA.
There are other sites with Neanderthal remains from this period, but the ones listed above have been among the most important. In the late 1970s researchers started to establish formal criteria, mainly on the basis of the bones discovered in the late 19th and early 20th centuries, to define the Neanderthals. Albert Santa Luca and Jean-Jacques Hublin came up with four unique characteristics of Neanderthal skulls. These are all fairly technical features towards the back of the skull and seem to be related to the skull architecture needed to support extremely strong jaw muscles. On the other side of the skull, the absence of a protruding chin may also have related to chewing ability. Neanderthal faces were thrust forward and some researchers have likened them to the aerodynamics of racing cars. Such faces may have made it easier for Neanderthals to use their jaws as a vice, and heavy wear patterns on Neanderthal teeth support this explanation (see p. 79).
The skull of La Chapelle-aux-Saints 1, found in 1908 as part of the discovery of the first relatively complete skeleton of a Neanderthal (see also pp. 140–41).
El Sidrón Cave in northern Spain has yielded remains of a dozen Neanderthals showing signs of cannibalism, from which DNA has been extracted. They may have been members of an extended family.
Jeffrey Schwartz and Ian Tattersall added a few more diagnostic criteria relating to the large Neanderthal nasal cavity. The Neanderthals had very large, broad noses, and anthropologists have offered competing and incompatible explanations for this, from an adaptation to cold climates (to warm the air during an intake of breath) to a cooling mechanism (to compensate for Neanderthals’ high metabolism). Others think that the noses were just a chance variation with no adaptive explanation required.
Chris Stringer has noted other distinguishing features, including barrel-shaped chests, short limbs and two heavy brow ridges (shaped as two linked arches over the eyes). As with the nose, there seems to be no widely accepted adaptive explanation for these features. The brow ridges were perhaps their most distinctive feature in comparison to Homo sapiens. Brow ridges of one form or another have been prominent features of human anatomy since the days of Homo erectus (which had a single ridge like a unibrow), making modern Homo sapiens, with our smooth foreheads, the exception.
What do Neanderthal bodies tell us about them? From the basic structure of the bones, we know that they were extremely strong. From the extensive level of injuries found on the bones and the relatively young estimated ages at death for Neanderthals (few Neanderthal skeletons belonged to individuals who lived past the age of forty), we can surmise that life was hard for them. They probably fought animals at close range as part of the strategy of ambush hunting that developed back in Homo heidelbergensis times. And, indeed, it is likely that they fought each other, as all human groups do, except that they had an enhanced ability to inflict lasting damage.
Like us, they were mostly right-handed, and their arm bones show that their right arm muscles were stronger than their left arm muscles. But unlike us, their right arms were very much stronger than their left arms, a difference rarely seen today except among professional tennis players. It is likely that Neanderthals performed repetitive activities such as scraping hides for clothing, leading to a pronounced asymmetry in their body strength. It is possible that clothes-making through scraping was a significant burden on the Neanderthals’ time. Bone needles are known only from modern human sites in later periods, and this probably means that Neanderthals did not have the advantage of tailored clothing.
Chris Stringer and a number of collaborators have looked at Neanderthal teeth, which leave growth marks not unlike tree rings. It has become evident that Neanderthals matured much faster than Homo sapiens. For example, a Neanderthal child from Le Moustier showed a level of maturation of a modern sixteen-year-old but has been estimated to have been only twelve years old. Modern humans’ more extended period of childhood meant that Homo sapiens had (and still have) more time for learning before having to take adult responsibilities. It is interesting to speculate how longer childhoods may have given modern humans an advantage, and it may just be that a longer period of teenage risk-taking helped spur a faster rate of innovation.
Vindija Cave, Croatia, is one of the sites to have produced Neanderthal bones from which DNA has been recovered.
Putting this together, Neanderthals grew up fast and died young. Most knew combat. Despite these hardships, they were a caring people. Some individuals – dating back to the Sima de los Huesos and Shanidar and continuing into the classic Neanderthal period – had suffered debilitating injuries (which we can see in their partially healed bones) and would have needed support in order to survive.
Many Neanderthal features, including their heavy build and stocky bodies, have long been interpreted as adaptations to a cold climate. As part of human variation today, there is a correlation between the latitude where a population lives and the stockiness of their bodies. The explanation for this is that the human body is better adapted to cold when its surface area is limited by shortened limbs, as this helps to conserve heat. This is known as Allen’s rule after the 19th-century Harvard zoologist Joel Asaph Allen. Another such rule is Bergmann’s rule, named after the 19th-century German biologist Christian Bergmann, which correlates cold temperatures with large overall body sizes.
Following these rules, Neanderthal bodies reflected their long exposure to cold compared with the lankier Homo sapiens. But the timing of the Neanderthal extinction is something of a paradox. Their bodies had adapted to cold during a previous severe glaciation. Around 37,000 years ago the European climate started another slow decline, culminating in the Last Glacial Maximum some 26,000 years ago. By the time of this peak glaciation the Neanderthals were already extinct. Why did they die out during a non-severe cold period during which the more tropical-adapted Homo sapiens were thriving? Their physical adaptations were clearly not giving them an edge.
A comparison of the anatomy and body shape of a Neanderthal and a modern human.
Researchers have estimated that Neanderthal thermoregulation would have given them only a small advantage over their Homo erectus forebears or Homo sapiens rivals, amounting to just 1°C increased tolerance to cold. During European winters and in glacial periods this would have been of little help, and the Neanderthals would still have been dependent on good clothing, fire and possibly a high-fat diet to stay warm. Yet their body mass and proportions came at a price. In comparison to the more gracile Homo sapiens, the Neanderthals would have needed more calories to support their muscular bodies. How did they find these large meals? To answer this, we turn to Neanderthal diet.
There are two ways to reconstruct Neanderthal diet. One is to look at the animal bones discarded at Neanderthal occupation sites. This method can tell us much about what species the Neanderthals ate, whether they selected game in their prime or settled for eating the old and infirm and in what seasons
they tended to butcher animals. But this method is far from comprehensive, for it excludes plants, the remains of which do not survive all that well, and large game which Neanderthals probably consumed at kill sites. There is the additional problem that animal carcasses may have been brought into caves by other carnivores.
To compensate for these shortcomings archaeologists are able to learn more from the ratio of certain isotopes in ancient bones and teeth. By extracting bone collagen (which is produced from dietary protein) from Neanderthal remains and looking at the ratios of stable carbon and nitrogen isotopes, researchers can get a picture of what kinds of protein they were consuming. Meat eaters tend to have different isotope ratios from herbivores, and archaeologists can compare the isotope ratios in Neanderthal collagen to the ratios found in other animals from the same area. This method, like carbon dating, involves the destruction of precious remains, however small, of the Neanderthals, so archaeologists are reluctant to do it too often. Luckily, stable isotope ratios can be discerned as part of the process of carbon dating, so both procedures can be conducted by the same lab on the same material.
The Neanderthals Rediscovered: How Modern Science is Rewriting Their Story Page 13