Masters of the Planet (29 page)

NEANDERTHAL DIETS

As we've seen, the genetic evidence hints that Neanderthals were always thin on the ground, and this is probably also reflected in the typically small size of the sites they left behind, as well as their low density. In both warmer periods and cooler ones, Neanderthals lived in seasonal environments that would not have been enormously productive of the kinds of plant foods necessary to sustain hominids; and at all times they would likely have been quite heavily dependent on animal fats and proteins to get by. Just how dependent clearly varied, though, and this variation seems to have been largely a function of time and circumstances, for Neanderthals were flexible foragers who knew how to exploit whatever the environment offered.

One study of adjacent occupation sites in western Italy was eloquent in this regard. About 120 thousand years ago, during a warm
period
(MIS 5e), Neanderthal occupations were brief, and the animal remains associated with them consisted mainly of the cranial remains of older individuals. The researchers concluded that the hominids at the site had scavenged the remains of animals that had died of natural causes: the heads were the last bits available when large carnivores had had their fill. In contrast, at 50 thousand years ago, when (coincidentally or not) conditions were much colder, the animal remains were those of individuals in the prime of life, and consisted of parts from all over the body. Together with greater densities of stone tools this suggested not only more sustained site occupation, but that the Neanderthals were using sophisticated ambush-hunting techniques to obtain carcasses that were brought back whole to be butchered at the home site. Archaeological evidence of this kind almost always gives an incomplete impression of the lives of the ancient hominids who left it behind, and it is never easy to interpret. Nonetheless, the contrast between the earlier and later occupations is striking; and at the very least it indicates not only that Neanderthal techniques of obtaining animal foods varied greatly, but also that their occupation habits did, too. These hominids were certainly not stereotyped in their subsistence strategies.

Flexible they may have been, but a powerful consensus is growing among archaeologists that under appropriate circumstances Neanderthals were top predators. Not only were animal products the main if not the only potential hominid mainstay at cooler times, but evidence is also accumulating that they routinely went after large-bodied mammals, some of them the most fearsome of all the creatures on the landscape. The most provocative such evidence comes from the study of stable isotope ratios preserved in Neanderthal teeth and bones. We've seen that carbon isotopes have been very informative about diet among the australopiths; in the case of the Neanderthals, an equivalent role has been filled by stable isotopes of nitrogen. It turns out that the ratio between the two isotopes
¹⁵
N and
¹⁴
N increases slightly in your tissues with every step you take up the food chain: the higher the ratio, the more meat there is in your diet. Starting in the early 1990s, scientists discovered that the bones of Neanderthals invariably showed higher
¹⁵
N/
¹⁴
N ratios than were found in the fossil bones of herbivores from the same place;
indeed,
they were right up there with the ratios recovered from wolves, lions, and hyenas—if not higher yet.

This observation fit well with the abundance of butchered herbivore remains typically found at Neanderthal sites. But the ultimate observation came in 2005, when a French team found an extremely high
¹⁵
N/
¹⁴
N ratio in the bones of a very late Neanderthal from a place called St.-Césaire. Since this value was well above what they had found even in hyenas from the same site, the scientists suggested that the only way in which Neanderthals could possibly have achieved such a high ratio was by specializing in the consumption of herbivores that were themselves enriched in
¹⁵
N. And the only putative victims were among the most intimidating of the many large beasts roaming the landscape: namely, mammoths and wooly rhinoceroses. What is more, the French scientists suggested that it would not have been possible for the St.-Césaire Neanderthals to have scavenged all the mammoth and rhino carcasses that would have been necessary to sustain the high nitrogen isotope ratios they had found in the hominids' bones. In their view, the hominids must have actively hunted the huge mammals, presumably as an important component of a long-standing dietary tradition. The case seems pretty strong, then, that Neanderthals were redoubtable hunters who, even at low population densities, were able to tackle some of the most formidable prey around. At their living sites they routinely controlled fire in hearths; and these fires doubtless provided a focus of their social activities, besides furnishing a means for cooking all that meat and for discouraging unwanted predators.

Still, it's important not to forget that plant foods must have played a significant role in the Neanderthals' diets in most places and at most times. This aspect of their food intake has been predictably neglected because plant remains rot rapidly, and rarely preserve in the archaeological record. However, scientific ingenuity is beginning to open up some amazing new avenues for investigation. For example, a recent report describes plant microfossils (both starch grains and phytoliths, tiny rigid bodies that occur in plant roots, leaves, and stems, and differ according to plant species) that were recovered from the plaque coating Neanderthal teeth from two famous sites. A dentist's nightmare had become a treasure trove for paleoanthropologists. One of the sites in question is
the
cave of Shanidar in northern Iraq, and the specimen examined dates from about 46 thousand years ago. Shanidar is, by the way, the site that has famously yielded the skeleton of an aged male Neanderthal with a withered arm. This appendage must have been useless to its possessor for most of his long life, and his survival has elicited speculation that he enjoyed the sustained support of his social group. The other site is the Belgian cave of Spy which, at about ten thousand years younger, falls very late in Neanderthal history.

Though far apart in time and space, and representing environments ranging from Mediterranean to cool temperate, the two caves tell similar stories. In both places the Neanderthals consumed a wide variety of plant foods that reflected the range of resources available in the local environment. There was no indication of specialization on particular plants, but in both places many of the foods would have required some preparation prior to consumption, and some starchy plant parts had indeed been cooked to render them more edible. There is, by the way, no contradiction between extensive consumption of starches and the nitrogen isotope record, because the isotopes only register the consumption of meat and of plant foods that are high in protein. At Shanidar the foods indicated by the microfossils include dates, barley, and legumes— items that would have been ready for harvesting at different times of year, thus indicating that foraging for plant foods was a year-round activity. All in all, this new study shows us that the essentials of the modern hunting-gathering style of subsistence had been established by the time the Neanderthals had entered the picture. Like
Homo sapiens
today,
Homo neanderthalensis
was an opportunistic omnivore, reminding us that despite our secondary adoption of a predatory lifestyle, we have never entirely put behind us our ancient vegetarian heritage.

NEANDERTHAL LIFESTYLES

Apart from being small, we didn't know until very recently what those Neanderthal groups that sat around the fire cooking their food were actually like. All we had as a basis to speculate on the subject were stone artifacts and broken bones, and the ways in which these were scattered around living sites. This scattering was typically (though not
invariably)
random, with little suggestion that the living space was divided into areas for specific activities such as butchery, stone knapping, sleeping, eating, and so forth. We routinely find such division of space at sites left by fully symbolic modern humans, so there is already some suggestion of different approaches to domestic life by the two species. But until recently, there hasn't been much to tell us how Neanderthal groups were organized. Now a team of Spanish researchers, working at the 50-thousand year-old Neanderthal site of El Sidrón, has come up with some intriguing suggestions based on both physical and molecular evidence.

The El Sidrón site itself is a long and complex warren of tunnels produced in the surrounding limestone by an ancient underground river system, and it has a complex history. Most notably, an extensive assemblage of Neanderthal bones was deposited in a single event on the bottom of one arm of the cave, when the ground surface above (or, just possibly, the floor of a higher tunnel) collapsed into the cavity below. Large numbers of knapped stones were intermixed with fossil bones and other debris. Many of the fragments could be refitted into complete cobbles, suggesting that the spot where the collapse occurred was a place where stone tools were made. The 1,800 fossil fragments found in the debris represent the broken-up remains of twelve Neanderthal individuals: six adults, three adolescents, two juveniles, and an infant. All appear to have already been dead when the collapse occurred, not long after their decease. More remarkably, not only had these Neanderthals been dead, but the researchers conclude that they had been the victims of a massacre, since many of the bones show marks of cutting and percussion consistent with defleshing, and probably cannibalism.

Evidence of defleshing is not uncommon on Neanderthal (and even
Homo heidelbergensis
) bones, and many scientists have argued that removal of flesh from corpses after death is not necessarily proof of cannibalism; but the case made that the hominid bones at El Sidrón were broken for consumption is a compelling one, and the probability seems to be growing that this behavior was indeed part of the Neanderthal repertoire. Interestingly, the El Sidrón researchers think that, in contrast to the “gastronomic cannibalism” seen at the Gran Dolina (i.e., cannibalism occasioned by habit, rather than by necessity), the El Sidrón
Neanderthals
were the victims of “survival cannibalism.” In support of this they point to the fact that the fossil remains bear clear signs of environmental stress, mainly in the form of an abundance of those defects in dental enamel formation that were notably rare at the Sima de los Huesos. If dietary stress was indeed a significant issue for these hominids, then it is likely that competition among contiguous Neanderthal groups for available resources was strong. Putting the various lines of evidence together, the researchers conclude that the twelve El Sidrón Neanderthals all belonged to a single social group that had been ambushed, killed, and consumed by another.

Two further observations support the notion that an entire Neanderthal group had perished in the El Sidrón event. One of these is that a group size of twelve, with a few adults of each sex and children of all ages, is pretty much in line with what you might expect. Specific estimates of Neanderthal group sizes are few and far between, but one recent study at the 55-thousand-year-old Spanish Neanderthal site of Abric Romaní concluded that groups occupying the rock shelter had varied in size from eight to ten individuals. If the Abric Romaní inhabitants were typical, and the estimates of their group sizes are accurate, it's even possible that the twelve individuals from El Sidrón belonged to a largish social unit by Neanderthal standards.

Still, wherever this band stood in the size spectrum, the notion that it constituted a single social unit was supported by analysis of its members' mtDNA, which had been excellently preserved in the cool conditions within the cave. For a start, diversity among the El Sidrón mtDNA genomes was very low, consistent with a family group. But most revealing was the finding that the three El Sidrón adult males had all belonged to the same mtDNA lineage, while each of the females had belonged to a different one. And here, for the first time, is a potential (though not definitive) message about the social organization of Neanderthals: that the El Sidrón males had remained in their birth group, while the females had married out of theirs, being dispatched at or soon after puberty to join a neighboring band. As one scientific colleague was quoted by the
New York Times
as saying, “I cannot help but suppose that Neanderthal girls wept as bitterly as modern girls, faced by the prospect of leaving close family on their ‘wedding' day.” This may be anthropomorphizing
a
bit—and it is certainly true that impassive female transfer is not that uncommon among primates—but it is difficult not to respond to the sentiment.

The inferences made by the El Sidrón researchers about Neanderthal society do not stop there. They note that a five- to six-year-old child and a three- to four-year-old were probably offspring of the same adult female. This suggests a birth interval of around three years, consistent with what was historically seen among hunter-gathering peoples. This in turn implies that Neanderthals achieved prolonged inhibition of ovulation, most plausibly through the expedient of protracted breastfeeding. An imaginative further conjecture comes from the material from which the El Sidrón stone tools were made: the nearest place at which it could be obtained was several miles away. Perhaps, the researchers speculated, the El Sidrón Neanderthals had incurred the wrath of the neighboring group into whose territory they had forayed to obtain it, and paid a heavy price in a reprisal raid.

Taken together, all of this tantalizing evidence from El Sidrón is helping create a more visceral picture of the Neanderthals than we ever had before. Knowing from high-tech laboratory analyses that tiny numbers of Neanderthals heroically hunted mammoths out on the tundra certainly evokes our admiration of these hardy and resourceful hominids. But this kind of information is profoundly different from contemplating the historical vignette of Neanderthal life—and death—with which El Sidrón presents us. The vision of a peacefully stone-knapping extended family of Neanderthals being raided, murdered, butchered, and eaten by a marauding group of their fellows is an unsettling one in the extreme; but then again, it is possibly not so different from what every modern watcher of crime-scene television is by now inured to.