Lone Survivors (25 page)

So we know that the Neanderthals suffered many bodily injuries, and in some cases it seems they must have had social support from others in their group to recover, or at least to prolong their survival. There is a particularly early example of this from the Sima de los Huesos site at Atapuerca in Spain, dating from about 400,000 years ago, where a child with a deformed skull and brain, perhaps caused by an injury sustained before birth, was almost certainly disabled physically and mentally; yet this individual was not rejected at birth and survived the most dependent stages of infancy, dying at around the age of eight, for reasons that may or may not have been connected with the disability. As we discussed earlier, the Atapuerca population lay at the very beginnings of Neanderthal evolution, and it seems that the Neanderthals continued this kind of social support, as may well have been the case for the wounded Saint-Césaire and Shanidar individuals.

Another individual from Shanidar may well demonstrate even higher and longer-lasting levels of social care: the Shanidar 1 man was probably about forty when he died, a very respectable age for a Neanderthal. Yet he had suffered a heavy blow to the left side of his skull and face—perhaps from a rock fall—and as a result may have been partly blind and deaf. Possibly connected with the incident, his right arm had been severely damaged: the upper arm had a badly healed fracture and was withered to a thin stump, and he had completely lost his lower arm and hand. His legs show that he was disabled in walking too, perhaps because the blow to the left side of the brain had caused paralysis on his right side, as may happen in modern injuries of this kind. Despite all those difficulties, he had apparently survived for many years, implying assistance and provisioning from others. Apes with arm or leg fractures or amputations can sometimes survive in the wild without social support, but for a Neanderthal living in the Zagros Mountains it seems likely that his injuries would have been an immediate death sentence without consistent help from his group.

There are several other examples of survival with impairment in Neanderthals, and also comparable examples from Africa: the 400,000-year-old Salé cranium from Morocco and the Singa cranium (more than 130,000 years old) from Sudan both show evidence of long-lasting and probably disabling deformation, yet these individuals survived into adulthood. In my view, this level of social support probably led to the practice of intentional burial, since, for example, leaving a body on the floor of a cave to which you might return could entail seeing your father, mother, or siblings picked over by hyenas or vultures. Later, with repetition and the addition of ritual, the rise of symbolic burials could have followed, with grave goods as tributes or offerings to help passage to the spirit world.

To what extent the Neanderthals shared this behavior is still hotly argued, and a few archaeologists like Robert Gargett even doubt that Neanderthals buried their dead at all, in which case all the supposed burials in caves were either accidental or the result of roof falls et cetera. But I think there is sufficient evidence for some level of ritual behavior in the later Neanderthals at least, including infants being buried with simple grave goods. However, it seems likely that one of the most famous examples, which gave rise to the notion that the Neanderthals were the first “flower people,” was the result of other, rather surprising, agencies. After the Shanidar 4 burial was excavated from this Iraqi cave in 1960, analyses showed that the sediments contained clusters of pollen, suggesting that bright flowers (perhaps even some with medicinal properties) had been strewn around the body. However, the zooarchaeologist Richard Redding subsequently excavated a number of burrows of a gerbil-like rodent found in the Zagros Mountains near Shanidar and noted that these animals stored flower heads in their tunnels. In turn, the anthropologist Jeffrey Sommer noticed that the original excavators had reported rodent bones and burrows around the Neanderthal skeletons; thus it seems likely that the supposed flower burial of the Shanidar 4 man had a more prosaic and less romantic explanation.

Nevertheless, the care that both Neanderthals and early moderns bestowed on other group members would have had both social and demographic effects, and this may provide further clues about why modern humans were ultimately the most successful of all human species. Earlier, we discussed the distinctiveness of human age profiles compared with those of apes: we have a longer period of infant dependency, reach puberty later, have later ages for first births but closer birth-spacings, postreproductive survival in women is very common, and overall we live longer. This means that humans develop and need much longer-lasting social ties, beyond those of their immediate kin, throughout their lives. There are probably specific genetic bases for our longevity. For example, it has been suggested that unique mutations in a gene for the cholesterol-transporting apolipoprotein E occurred about 250,000 years ago. The variant ApoE3 lowers the risk of many age-related conditions such as coronary disease and Alzheimer's, and it will be interesting to see whether this variant was also present in the Neanderthal genome.

As discussed in chapter 3, the Neanderthals had a human rather than an apelike developmental pattern, but at the same time their lives must have been stressful. About twenty years ago, a nurse turned anthropologist, Mary Ursula Brennan, compared the pattern of growth interruptions in dental enamel formation in Neanderthals and early modern humans and found these indicators of childhood stress were much more common among the Neanderthals. In old age there are further indications of the problems that they and our African ancestors faced (again, from research using teeth—this time to assess the longevity of Neanderthals and early modern humans). While Erik Trinkaus found little difference in survivorship between archaic and modern humans, the anthropologists Rachel Caspari and Sang-Hee Lee came to different conclusions. Their studies were conducted using a technique called
wear seriation
, in which the degree of wear of each molar tooth is used to assess the relative age of an individual. So, for example, the age of third molar (wisdom tooth) eruption was taken to mark adulthood, and when cumulative molar tooth wear indicated an individual was about double that age, they were considered to have reached older adulthood and could potentially have been grandparents. Additionally, Caspari used microCT (see chapter 3) on some dental samples as an aging guide, since the pulp cavities of molars decrease in size through life as dentine is accumulated in them.

Caspari and Lee carried out comparisons ranging from ancient hominins such as australopithecines through to Neanderthals and Cro-Magnons, assessing the ratios of young adults to old adults. They found that only the Cro-Magnons of Europe had a high representation of middle-aged to old individuals (about four times as many, compared with their Neanderthal predecessors in Europe, and even more distinct when compared with earlier humans and prehumans). Interestingly, the Skhul and Qafzeh early moderns were no different from the Neanderthals in their relatively low survivorship to middle and old age. This in turn suggested that cultural, social, or environmental factors—rather than biology—were probably at work in catalyzing the change in age profiles; otherwise the difference should already have been showing in the 100,000-year-old moderns from Israel. If the Cro-Magnons had had more older adults, they would have had more reproductive opportunities, packing extra children into each fertile life span, and there would have been more intergenerational overlap, allowing greater transfer of knowledge and experience down the years. In addition, some data from recent humans suggest that the frontal lobes of the brain, which are closely involved in the planning of behavior, continue their wiring-up until at least twenty-five years of age, so this is something that might only be complete in adults who survived that long. But harking back to the Grandmother Hypothesis and alloparents, these results suggest that their beneficial effects would have barely been felt in early humans, including the Neanderthals. Caspari's study of the seventy-five or so Neanderthals from the site of Krapina in Croatia showed no individuals were likely to have been older than thirty-five at death, so there were not many grandparents around, and that would have been even worse news when so many younger parents were evidently dying before they reached thirty. Thus orphaned Neanderthals would have mainly had to rely on older siblings rather than grandparents for social support.

It was perhaps only with the broadening of food supplies and of those involved in its collection that the change in age profiles could develop in modern humans. And something else of great importance would have been enabled by the overlap of three or four generations in the Cro-Magnons: extended kinship. An example of how important this could have been is shown by the complex kinship systems of many Australian aboriginal groups, which determine not only where individuals are placed in society but what their duties are and how they will be treated. The system determines who can marry whom, what roles they will take in ceremonies, and how they should react to both kin and nonkin (for example, social intimacy, joking relationships, or—cue for many comedians—avoidance relationships such as between a mother-in-law and son-in-law). And when times are hard, groups may need support—or at least tolerance—from each other, such as when a water hole needs to be shared. Then it is critical for negotiators to establish if they are kin or potential enemies by tracking back their genealogies to see if they can find relatives (who may be long dead) in common, or if there is a history of unresolved disputes. All of this requires extensive records and mapping of relationships, which, in the absence of written or digital storage, is only feasible when several generations overlap, in order to provide a kind of collective memory.

In that last example, from Australia, we see the two opposing forces of intergroup relations at work in modern humans—cooperation and conflict—and undoubtedly these have both been important in influencing recent human evolution. I have spent some time discussing the role of mutual social support within groups, but humans undoubtedly also evolved vital mechanisms to defuse potentially aggressive encounters with neighbors. These would have included intermarriage, so that potential enemies could instead become kin, and it is possible that some of the symbolism we see in the Paleolithic—whether it is strings of beads as friendly trade items or cave art intended to signal territorial boundaries—was aimed at managing external relations. The anthropologists Robin Fox and Bernard Chapais developed the argument that the exchange of mates, and in particular the exchange of women, associated with marriage, was the critical evolutionary step in the development of the kinship systems that can be found in hunter-gatherers and pastoralists around the world. Two critical building blocks in such relationships are found in primates:
alliance
and
descent
. Alliance consists of stable breeding bonds, such as a male gorilla and the several females with whom he mates. Descent consists of groups of related individuals, such as female monkeys who share a mother, who bond, and who can acquire the status of their mother and pass it on to their offspring.

But human kinship combines both of these, since the mode of descent (traced through one of the parents) is a mechanism for the construction of alliances. So although offspring disperse, as one sex (usually women) marries outside their immediate group, they maintain their original ties of mutual descent. The change from relatively promiscuous mating to pair-bonding allowed the unique recognition in humans of fatherhood, of paternal relations, and of “in-laws,” all of which were essential building blocks in truly human kinship systems. We have little evidence of the kinship systems of the first modern humans or of the Neanderthals (although see chapter 7), but the proliferation of symbolic objects such as beads 80,000 years ago suggests to me that mate exchanges (and most commonly these are exchanges of females) were probably in place between human groups in Africa.

However, the injuries carried by early humans, and especially the Neanderthals, show that encounters with others in the Paleolithic were not always friendly, and although there is less evidence of such wounds in early modern humans, researchers like Raymond Kelly believe that the potential for both conflict and coalitions was also a significant force in the development of modern humanity. I discussed the possibility that only modern humans had projectile weaponry in relation to the rib wound on the Shanidar 3 Neanderthal, and the emergence of “killing at a distance” would have been a threat to humans as much as to hunted prey. Male chimps form aggressive coalitions to carry out lethal raids on other troops, so it is likely that such behavior was part of our evolutionary heritage, and that tools in the form of rocks, clubs, sharp stones, or pointed sticks would soon have been recruited for defense or attack (as in one of the famous opening scenes in Stanley Kubrick's film
2001: A Space Odyssey
). As Darwin put it in 1871: “A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection.” Over the last 130 years, such views have formed the basis of ideas on “group selection” by distinguished researchers ranging from Arthur Keith and Raymond Dart to Richard Alexander and James Moore.

But from the 1970s onward, work by biologists such as William Hamilton, Robert Trivers, and Richard Dawkins emphasized the selfishness of genes and undermined the basis of many previous formulations of group selection. Selection acts only on genes or individuals, not populations, and while altruism (selflessness) can evolve, it will only be favored in genetically closely related groups. Mathematical tests showed that group selection would fail when there was even a small amount of migration between groups, or when “cheaters” exploited the benevolence of others to propagate their own genes. However, more recently, biologists and anthropologists such as Paul Bingham and Samuel Bowles have returned to the issue by recruiting weaponry and genes to the cause of group selection. The argument goes that by coming together to use effective projectile weaponry, individuals reduced their separate risks, and thus coalitions of warriors would have been advantageous for group defense and offense. Bingham proposed that this development would also have been important within societies by deterring free riders who tried to reap the rewards of group membership without contributing their fair share of commitment to the associated costs or risks. However strong individually, they could soon be brought into line when faced with a coalition of spear-armed peers, who could act as general enforcers of within-group rules and solidarity.