How To Think Like A Neandertal, by Thomas Wynn and Frederick L Coolidge, Oxford University Press, 224 pp, £12.99, ISBN: 978-0199329229

Wynn and Coolidge’s book opens with the statement: “Neandertals were prehistoric people who evolved in Europe and flourished between 200,000 and 30,000 years ago.” By referring to Neandertals as “people” the authors touch on some of the questions that have fascinated the public since a Neandertal skeleton was first recognised and described as an early human fossil in the late 1850s. Were Neandertals like us? How did they live? How did they think? How did they become extinct? And what were their relations with humans?

Were you to quickly pass a Neandertal man on the street today, he might almost pass for a modern human. But if you took a closer look, a number of differences would become apparent. His face would be larger than a modern human’s, or homo sapiens sapiens, particularly long from forehead to chin, with a pronounced brow ridge, or swelling of the bone above the eyes. His nose would be larger and broader than most modern people’s. He would have a large jaw but lack a protruding chin and his teeth would be bigger. His whole head would be larger, in part to accommodate his big brain – Neandertal brains were about 10 per cent larger than ours. The widest part of his head would be in the middle, not closer to the top like your own. He would be shorter that the average modern human. His torso would be wider, with broad hips and barrel chest. His arms and legs, in particular forearms and lower legs, would be shorter relative to his stature. He would be extremely muscular. In the bulk of his shoulders, arms, back and legs, he might resemble a competitive weightlifter, though he would have achieved this effect without having to put in any hours in the gym. In a weightlifting contest only the strongest of modern humans could compete with him.

Many Neandertal body characteristics would seem to have been appropriate for the relatively cold climates they occupied; Europe was not always as warm as it is today. Their shorter limbs would result in a lower surface to bulk ratio, which is better for retaining heat. The same could be said of their shorter stature and broader torsos. Not all of the Neandertal features that differ from our own can be explained by cold adaptation and some studies suggest that Neandertals actually resemble many prehistoric humans, including homo heidelbergensis, their immediate predecessor, more than they resemble us. So perhaps it is we who changed and adapted to be different from our predecessors rather than Neandertals.

No fossilised Neandertal brains have yet been discovered, and it is unlikely that any ever will be, though Neandertal braincases have been found. However, only limited amounts of information on the actual brains can be inferred from these. Neandertals were expert at removing stone flakes from a stone core (stone knapping). This they did to create sharp stone tools which could be used as knives or spear-heads. Neandertals were able to generate different kinds of flakes with different edges to suit different purposes and were able to treat the stone core in such a way that it would yield the maximum possible number of tools. The techniques they used were advanced and complex. Neandertals would haft sharp stone points onto wooden shafts to create thrusting spears. In at least one case the stone spear-heads were hafted to the wooden shaft using bitumen, a kind of natural asphalt, as glue. In another case pitch made from birch bark was used. Neandertals may also have lashed spear heads to shafts when no glue was available. However they did it, the hafting of spearheads to wooden shafts was a piece of engineering that significantly enhanced their primary weapon. It is a piece of Neandertal innovation, though it is the only example of Neandertal innovation that has been discovered.

Paleoanthropologists have used used body weight and estimates of levels of physical activity to estimate that the average neandertal needed somewhere between 3,000 and 5,500 calories per day (most modern humans require between 2,000 and 2,500). For much of their time they lived in habitats that had little to offer in the way of plant foods so they would have relied heavily on animal products for their daily caloric requirements. Fire and cooking would have been essential to Neandertals’ survival in glacial Europe and were an established component of hominin life long before the time of Neandertals. Further evidence as to the constituents of their diets comes from bone chemists, who have been able to tell us how much meat Neandertals ate based on the skeletons that have been found. Not only have they been able to tell us how much meat they ate (a lot), they have been able to tell us what animals they ate. Particularly striking here is the consumption of large quantities of mammoth and rhino – very large, dangerous animals. Neandertals were “top predators”.

While throwing spears have been found in Ethiopia dating from about 280,000 years ago, this particular weapon has never been associated with Neandertals who would have used thrusting spears and would have had to get in very close for the kill; it is unlikely that a single thrust of a stone-tipped spear would have killed a mammoth or a rhino. This kind of hunting would probably terrify most modern humans so we must assume that Neandertals were a lot tougher and braver than us. Homo sapiens sapiens, living at the same time as Neandertals, also hunted big game, though not to the same extent, and they used throwing spears and so were able to keep a safer distance.

In the early 1990s researchers compared the post-mortem injuries of Neandertals to those of different groups of modern humans. The study revealed that Neandertals’ set of injuries most closely resembled, in fact were almost indistinguishable from, those of present day rodeo-riders. Modern humans living at the same time as Neandertals show far fewer serious injuries. The number of injuries observed can probably be explained by the sort of close-quarter hunting Neandertals participated in.

One of the most famous Neandertal individuals, and the most complete Neandertal skeleton that has been found, is Shanidar 1, who lived and died in Iraqi Kurdistan about fifty thousand years ago. Shanidar 1 was male, between thirty and forty when he died, about 5’8” tall. His skeleton also reveals the many physical traumas he suffered during his life. His right arm had been injured beyond use or else amputated above the elbow many years prior to death. Several bones in his right foot had been badly broken leading to serious arthritic degeneration in his right ankle and knee, while his left leg, knee and foot were normal. He had received a devastating blow to the left side of his face which had crushed his left cheekbone, the left side of his cranium and probably blinded him in his left eye. This facial trauma had also healed many years before his death. He had received a separate wound to his right scalp, deep enough to cut the bone. This too had healed before his death. Whether these injuries occurred due to a single incident or separate events is not known. They may have been the result of a hunting accident or have been due to a violent interaction with another Neandertal. After all, interpersonal violence is a characteristic not only of modern humans but of many non-human primates, including chimps, our closest cousins. While his injuries demonstrate that Shanidar 1 had a very tough life, perhaps what is most significant about them is the fact that he survived them. He must have been cared for and this is a huge clue to the Neandertal mind. He would have, for some time at least, been incapacitated, unable to take part in hunting and unable to care for or feed himself.

Neandertals lived in small face-to-face groups, that is groups of individuals more or less in direct contact. These groups tended to be much smaller than those of homo sapiens sapiens in prehistoric times. In this respect Neandertals were different from modern human hunter gatherers. One Neandertal skeleton became known as the “Old Man of La Chapelle-aux-Saints”, because it was assumed, due to the state of his skeleton, that he was extremely old when he died fifty thousand years ago. He suffered from severe arthritis, had a degenerative hip socket, a healed broken rib, and had lost most of his teeth. It was later discovered that he was not so old after all, between thirty and forty when he died, though this was fairly old for a Neandertal (examination of prehistoric skeletons suggests that one-third of Neandertals lived past the age of thirty, while the figure is two-thirds for prehistoric modern humans). In 1910 French anatomist Marcellin Boule described him as hunched over and unable to straighten his legs: this description is probably responsible for the mistaken image most of us have of Neandertals as hunchbacks. Shanidar 1 and The Old Man of La Chapelle were not exceptions. Any Neandertal who lived to “old age” (over thirty) had suffered major injuries and must have been cared for when they were no longer able to hunt, carry anything or even walk. The Old Man of La Chapelle would not have been able to chew his food at the time of his death, or for several years before, and this at a time when Neandertal diets were almost entirely carnivorous. Somebody probably chewed his food for him, a solution often practised by modern people with the same problem. He would not have been much use in a hunt, being unable to run fast, deliver powerful blows or carry much for several years prior to his death.

This caring aspect of Neandertal behaviour could be seen as similar to our own. However, a difference is apparent in the size of the groups in which they lived and in the fact that Neandertals appear not to have mixed much with other social groups. They very rarely travelled outside of their own well-trodden areas of a few kilometers. Perhaps this suggests that they were less curious or adventurous than homo sapiens sapiens, more shy or more nervous of the unfamiliar.

The question of whether or not Neandertals had language has still not been definitively answered. Language is the trait that is seen as unique to our species, setting us apart from animals. Given this, the question of whether Neandertals could speak is particularly fraught. Neandertal language is the subject of intense academic debate and much literature has been produced on the subject. None of the anatomies required for speech (vocal cords, throats, tongues, lips) or detecting sound (cochlea) are preserved in the fossil record. However, the Broca’s area, part of the frontal lobe known to be associated with speech production, is enlarged in the Neandertal brain, as it is in our own. It is also unlikely that Neandertals could pass on their skills, as for example in stoneknapping, without language; hunting probably also required linguistic communication. If they did have a language, its form would probably have been quite remote from our own, with different vowel and consonant sounds and the use of more stock phrases, given that there would have been less working memory and consequently less ability to construct complex sentences.

Most modern human cultures have believed in some sort of continuance of the person beyond death, though the understanding of this continuance can take highly varied forms. And without exception modern human societies perform rituals relating to death, often elaborate and time-consuming ones. The first Neandertals discovered were found in what were thought to be graves, and this led the original archaeologists working on them to infer that they had undergone a ritual corpse treatment and therefore must have had a religious sensibility. Later studies suggested this assumption might have been premature. Not all of the Neandertal skeletons that have been found had been buried in graves and in some cases the “graves” in which Neandertals were found have been brought into question and may in fact, have been erosional pits that can be explained by natural processes. However, there are many examples of Neandertal skeletons in which the bodies must have been intact prior to being covered by sediment. All this suggests that Neandertals did perform mortuary treatment but that it was minimal. The “graves” in which Neandertals have been found are all shallow and could not have been expected to protect a corpse for a length of time – this may explain why we have not discovered more Neandertal skeletons – and they may have taken advantage of natural depressions in the ground rather than dug new ones. Neandertals certainly did not just leave corpses where they died; they invested labour into moving them and protecting them but we cannot conclude that they did any more than this.

Neandertals probably harboured the same fear of death that we do, an ancient response that has evolved to maximise self-preservation. While they appear to have been willing to take great risks when hunting, they may have calculated risk differently from us and must have been more stoical about injury and physical pain. They would have mourned the deaths of loved ones. Chimps mourn the loss of an infant or a close companion and there is no reason to think Neandertals would have been any different. Futhermore, their corpse treatment suggests that mourning lasted more than a few hours or a day. The small size of Neandertal social groups would suggest that the social disruption caused by a death must have been felt. Sites have been found where Neandertals inhabited caves in which other Neandertals had been buried, living among their bones. Perhaps this means that they were less sentimental than modern humans or perhaps it is an indication of extreme pragmatism – if a cave can make a suitable home then why not use it regardless of who is buried there?

There is reason to believe that Neandertals practised cannibalism and there is strong evidence to suggest that when this occurred it was a purely pragmatic practice: in other words it was driven by desperation and to avoid starvation. At one site in France the skeletons of six butchered Neandertals were found among the carcasses of red deer and goat. These had not been buried and the bones bore the same butchery marks as those of the other animals. While cannibalism does exist in modern humans it is usually a ritual practice, either the consumption of a defeated enemy to absorb some of his powers, or of elders, as a form of respect. However, archaeologists have discovered examples of pragmatic cannibalism carried out by modern humans in prehistoric times, and indeed there are examples in our own times.

There is little evidence that Neandertals performed rituals of any sort. Corpse treatment was ad hoc, bodies were buried with no goods or standard orientation. It is difficult to assign a rule-governed ritual to their treatment of the dead. While it is possible that Neandertals performed elaborate death rites that are not apparent in the archaeological record, it seems unlikely. Death rites or rituals relating to death are essential in modern societies to help people deal with the loss of a loved one. The fact that these appear to have been absent in Neandertal culture may indicate a difference between Neandertal psyches and our own, or perhaps the absence of ritual is merely as a result of the Neandertals’ small social groups.

Again, there is little evidence to suggest that Neandertals had a symbolic culture, though we should remember that unambiguous examples of symbols from modern humans are very rare until well after thirty thousand years ago. While the absence of surviving examples of symbols in the Neandertal record is not in itself evidence for the absence of symbolism in the culture there is little indirect evidence remaining to indicate symbolism through decoration, burial or fire.

There are no examples of cave-painting by Neandertals. All cave painting was carried out by modern humans. It is a little unfair to see this as an example of our cultural superiority, partially because very, very few modern humans ever crawled into caves to paint animals on the walls. Pigments such as ochre and manganese dioxide have been found at Neandertal sites. We can only speculate as to what they were used for. They may have simply been a component in Neandertal technology or they may have been used in body decoration. In some Neandertal sites archaeologists have recovered rock crystals that came from elsewhere, perhaps kept for their aesthetic value. At two sites perforated shells have been found that may have been worn as pendants.

Neandertals most likely had pair-bonding (or marriage); we cannot say if they experienced romantic love. The small groups occupied by Neandertals would have been based around the family unit. Inbreeding is not good for evolution or for the persistence of a species, therefore we can be certain that Neandertals married into different social groups. Most likely either Neandertal boys or girls left their own social group to join another when they had reached sexual maturity. Given how rarely Neandertal groups interacted with other social groups this must have been an intimidating experience for an adolescent leaving their family. Recently published evidence from one Neandertal site in which the archaic DNA was analysed suggests that all the males in the group were related but the females were not, indicating that it was the girls who in this case had left their families. Interestingly, the division of labour between men and women seems to have been much less well defined than in modern humans, with Neandertal men, women and even children participating in hunting. This is apparent from the similarities in the injuries and wear and tear that can be seen on their skeletons.

Our evolutionary history separated from Neandertals about 500,000 years ago. Our common ancestor, homo heidelbergensis, radiated out of Africa and into Europe, and the two populations then became isolated due a prolonged glacial period. Neandertals evolved in Europe about 200,000 years ago and spread as far east as Uzbekistan and throughout most of the Middle East. Modern humans evolved in Africa and moved into Asia less than 60,000 years ago and into Europe about 40,000 years ago. In 2010 Svente Pääbo and colleagues at the Max Planck Institute in Leipzig published a paper on their attempt to map the entire Neandertal genome. The paper concluded that Neandertal DNA is 99.84 per cent identical to our own (our closest living relatives, chimps, share 98.8 per cent of their DNA with us). But it also included the memorable finding that most modern humans (all those of European or Asian descent) possess some Neandertal DNA (between 1 per cent and 4 per cent), indicating that there was interbreeding and that we are compatible enough with Neandertals genetically to cross-breed and for the progeny to survive and go on to procreate.

It is interesting to dwell on how this interbreeding took place. The Neandertal DNA examined for Pääbo’s study (from the bones of three women who died in Croatia 45,000 years ago) showed no specifically modern human genes. So while we possess some Neandertal DNA they do not appear to have taken any homo sapiens sapiens DNA. This one-way gene flow influences our line of questioning on this interbreeding. How did modern humans and Neandertals interact? Were there mixed groups or is violent interaction more likely? Perhaps pair-bonds formed between modern humans and Neandertals. However, the fact that the gene flow is unidirectional suggests that the interaction may have been more violent. A child conceived through force would be raised within the mother’s community and most likely would go on to mate with other members of this community or at least of the same species as their mother. The fact that no modern human DNA was discovered in the Neandertal bones examined suggests that interbreeding took place mostly or exclusively between Neandertal men and modern human females, and the unavoidable implication is that this was a violent interaction. Another possible explanation for the one-way gene flow could be that half-Neandertal children raised with modern humans would have a better chance of surviving than half-modern human children raised by Neandertals. Neandertals had tougher lives than modern humans living at the same time, as evidenced by their skeletons. If they did reach adulthood, a half-homo sapiens sapiens in Neandertal society might not have appeared an attractive mate due to lack of bulk or musculature; this would probably have been true for women as much as men since both had similar roles when hunting.

The last Neandertal died somewhere in Spain or Portugal about 30,000 years ago. They had existed, and thrived, for about 170,000 years, so it does not make sense to suggest that the Neandertal characteristics that distinguish them from ourselves were inherently disadvantageous. So why did they disappear? And is it possible we played a role in their extinction? No species in the history of our planet has been as efficient as modern humans at destroying other species and their habitats. We are only now starting to come to terms with just how destructive we have been. Is the extinction of the Neandertals simply an early example of this tendency? We had more tools, though not many more. Is this what allowed us to survive after them? The Earth’s climate cooled dramatically 30,000 years ago. This would have put both Neandertals and modern humans in Europe and Asia under increased pressure. Perhaps when modern humans and Neandertals were in competition for dwindling resources we were able to adapt more quickly. Perhaps our larger group sizes gave us an advantage. However it is that Neandertals disappeared and whatever our role in their extinction was it is interesting to reflect that so many of us carry Neandertal DNA with us today, and the fact that 30,000 years after their extinction we are still carrying their DNA with us suggests that it may have given us some evolutionary advantage.

22/04/2014

Eva McGuire is a research fellow at the School of Physics, Trinity College Dublin.