This is an incredibly moving hypothetical story that spotlights the essential humanity of these ancestors of the Neanderthals. A close look at the fossils reveals how much like us they were. For example, in contrast to earlier hominins who were more balanced in their handedness, they were mostly right-handed, which we can see from their stronger right arm bones and leg bones, and also from the imprint of their brain shape on the inside of their skulls. The population at the Sima also seems to have been keen users of toothpicks, which have left grooves on their teeth.
The difference in body size between men and women (sexual dimorphism) at the Sima is similar to that in our species. This is a sign of modernity because in non-human primates and early hominins, males are much larger than females, while in modern humans the males are only slightly larger. Many researchers believe that the reduction in sexual dimorphism accompanied a shift from a male-dominated harem-type mating arrangement to a simpler, two-females-for-one-male polygamy or even pair-bonding monogamy, as predominates today. In short, the people of the Sima were likely right-handed individuals who entered into arrangements similar to our nuclear family units and placed an emphasis on dental hygiene.
At the same time, the men and women of the Sima did not look or behave quite like us. Their thick leg bones show that they were very muscular, probably even more so than the classic Neanderthals of 60,000 years ago, who had been regarded as the most heavily built human ancestors. The people of the Sima had bodies like the strongest modern rugby players or American football players. Many of them had brains that were as large as ours, but flatter. Their skulls were long, with low foreheads, prominent brow ridges, powerful jaws and no jutting chins. From wear patterns on their teeth, they must have used their jaws as a ‘third hand’ to hold meat, skins or plant material while they used their free hands for cutting.
At the Sima we have an early example of the tension between the physical uniqueness of the Neanderthal form and their behavioural similarity to early Homo sapiens. According to Antonio Rosas (see p. 143), a palaeoanthropologist who launched his career studying the human jawbones at the Sima, ‘Neanderthals are, let’s say, “a distinct biological entity” (distinct from modern humans), whose anatomy and, apparently, also physiology are visibly different from ours. But, on the other hand, the more data we gather on their behaviour and reproductive biology, the more similar they seem to be to what we call the “modern human pattern” (something perhaps weakly defined). What is behind these two extremes of reality is something that, for me, is becoming challenging to reconcile.’ Resolving this tension is central to understanding what it means to be human.
One definition of humanity is our capacity to care for the old and the sick. For this reason, perhaps the most noteworthy individual in the ossuary is represented by Skull 5, an elderly person (which, in Palaeolithic terms, means over fifty years old) who had serious dental problems and a brain size smaller than the modern human range. This is the best-preserved fossil human skull from anywhere in the world (see p. 69). He (for we presume he was a male, judging by the proportions of the face) must have had trouble chewing his own food. His presence in the Sima is just another part of the mystery of how this population came to be preserved here.
It is impossible to tell from the stratigraphy whether the bones accumulated as a result of a single catastrophic event, as the excavators suggest, or more gradually. One can think of all sorts of scenarios in addition to the idea of an ecological crisis. Perhaps the single child in the group wandered into an uninhabitable cave and fell in a pit. Then one by one the rest of the clan became trapped in the course of failed rescue attempts. Or perhaps the young adults were adventuresome cave explorers who died in a series of tragic events over many generations.
Other researchers look to a more conventional alternative – that the bodies, along with cave bears and other predators, were first deposited elsewhere in the cave system and then washed down into the Sima as a mixed, disarticulated mass. The archaeologist Paul Pettitt describes this as an early example of funerary caching, or the abandonment of human corpses in a preferred location. This theory, however, does not quite explain the relative absence of young and old or the fact that the skeletons seem to be complete. Sima de los Huesos, the earliest known site of the Neanderthals’ ancestors, is an ancient mystery that still holds many secrets.
Becoming Neanderthal
One can feel spoiled after looking at such sites as Sima de los Huesos and Boxgrove. In contrast, the human fossil record over the next few hundred thousand years, leading up to the appearance of unmistakable Neanderthals, is fragmentary and not well dated. Each of the fossils from this time has a unique mixture of Neanderthal- and erectus-like traits, making it difficult to map an evolutionary trajectory from heidelbergensis to the Neanderthals.
In the absence of good dates, it is common to estimate ages based on how Neanderthal-like fossils look. As dating methods have improved, it has become clear that Neanderthal traits appeared earlier than previously thought. The bones from this period are frequently revised back in time, sometimes by hundreds of thousands of years. It is likely, as more dates become available, that there are surprises still to come.
One key unresolved question is whether the whole population of Europe evolved into neanderthalensis, or whether there was more than one species present. Some researchers seem tempted by the two-species scenario. Chris Stringer has noted a suggestive difference in stone tools, whereby handaxes and flake tools (the latter in an industry called the Clactonian, named after Clacton-on-Sea, a seaside resort in Essex, England, where such tools were found) are never found in the same archaeological layer, and thinks this might indicate two separate populations.
Might the ‘Clactonian people’ represent a less successful branch of the human family tree, separate from the ‘handaxe people’, who were evolving into Neanderthals? We remain sceptical that the absence of handaxes – a tool that was used by a number of different forms of human – might indicate a separate species. Yet the pattern of fossils does seem to allow for the possibility that what we attribute to the heidelbergensis population of Europe was really two species.
The Petralona affaír
Locked in a vault at the University of Thessaloniki in northern Greece, shielded from the controversies that surround it, lies one of the best-preserved Homo heidelbergensis skulls ever found. When locals on the nearby Halkidiki Peninsula uncovered it in Petralona Cave in 1960, it caused a stir. But few could have foreseen how this key piece of the puzzle of Neanderthal origins would be the focus of a decades-long legal dispute.
The protagonist of this tale is Aris Poulianos, whose career in Greece contains no academic appointments outside of the Anthropological Association of Greece, an organization he founded and presided over for decades until he handed it to his son, Nikos. From this base, he came to have complete control over the excavation rights as well as tourist access to one of Europe’s most important Palaeolithic sites. To understand how this came to be, we must delve into the polarized political history of a country that still bears the scars of the Second World War and a subsequent civil war between rival resistance factions.
According to the Anthropological Association’s website, Poulianos fought with the communist resistance to Nazi occupation. After the war, he attained a PhD on ‘The Origins of the Greeks’ in Moscow before he returned to Greece in 1965 in the hope of studying the Petralona skull. He soon entered the civil service as a scientific adviser. In 1968, using his position as vice-president of the Greek Speleological Association, he began digging in Petralona. The Archaeological Service soon put a halt to the project, however, and Poulianos was expelled from the Speleological Association.
Cast of the skull found at Petralona Cave on the Halkidiki Peninsula in Greece.
The reversal of fortune that handed the site back to Poulianos was a consequence of the reaction to the right-wing military junta that had ruled Greece from 1967 to 1974. The junta was notorious for its repression of academ
ic freedom, and Poulianos, who had been imprisoned in the early days of the regime, could portray himself as a scholar oppressed for his political views. In 1974 the newly restored democratic government granted him an excavation permit for Petralona, and in 1979 he signed an agreement with the Greek National Tourism Organization to conduct further excavations and develop the site as a tourist attraction. In 1983, under a left-wing government, the Greek state expelled Poulianos from Petralona a second time, and he turned to the courts. The government alleged that Poulianos was not excavating in a scientific manner and was destroying the site.
Poulianos has sought to portray the skull and the site in superlative terms. First, he insisted that the skull is the oldest in Europe. In a paper in 1971, he dated it to 70,000 years ago, which he claimed made it the oldest known at the time. In 1981 he added a zero to the date, making it 700,000 years old, maintaining its most ancient status in the light of more recent discoveries. Poulianos retrospectively changed the stratigraphy of the find, moving it down from Layer 10 (as he said in 1971) to Layer 11, a level he originally claimed was empty of any human remains or artifacts.
Scientific dating techniques now place the skull between 160,000 and 620,000 years old, and the prevailing view is that the true date lies close to the midpoint between these extremes. When Chris Stringer, of London’s Natural History Museum, argued for this date at a conference in 1988, Poulianos rushed the stage and had to be restrained (as recounted in James Shreeve’s excellent book The Neandertal Enigma).
Poulianos’s strong feelings about the skull’s age are but one part of an increasingly idiosyncratic view of the prehistoric past. He has used the skull to name a new species, Archanthropus europeus petralonsiensis, which he alone recognizes, and which he believes is somehow ancestral to the Sarakatsani, a modern population of nomadic pastoralists who inhabit the same area. He claims to have uncovered bone fragments from fifteen other individuals in Petralona, although he has never published evidence of this. What he has published are pictures of tools associated with the skull, but these do not appear to show evidence of being anything other than unworked rocks.
With the entry of Poulianos’s son on to the scene, the Anthropological Association of Greece has made more incredible announcements. It now claims to have found evidence in Petralona and the nearby site of Nea Triglia of a sculpted figurine from 500,000 years ago, fire from 1 million years ago and another new species, Homo trigliensis, on the basis of 10 to 11 million-year-old stone and bone tools. These dates are at best controversial – the last one outlandish – and have not found support in international peer-reviewed periodicals.
In 1996 Poulianos won his legal battle with the Greek government and, for reasons of preserving ‘intellectual freedom’, was able to take total control of Petralona the following year. The Ministry of Culture tried on numerous occasions since then to regain possession of the cave, and finally succeeded in 2011. The Petralona skull, meanwhile, remains under lock and key.
What do the bones tell us about the origins of the Neanderthals? Among the oldest dated fossil remains of Homo heidelbergensis are the lower jaw from Mauer that gave the species its name and the shin bone and two teeth from Boxgrove, all about half a million years old and too fragmentary to be very revealing. The cache at Sima de los Huesos may also be very old, as may the skull from Petralona, which was the most complete known Homo heidelbergensis skull before Skull 5 was uncovered at the Sima. Like so many heidelbergensis fossils, the Petralona skull has its own particular mixture of modern and archaic traits and, as we have seen, its exact age is unknown.
The face of the Petralona skull looks even more Neanderthal-like than Skull 5, while the back of its head is closer to Homo erectus. At the front of the skull, its massive brow ridge is reminiscent of erectus, but unlike the heavy ‘unibrow’ of erectus, it is individually arched above each eye socket and is hollowed out by large air chambers called frontal sinuses, similar to the Neanderthal form. Its cheekbones and large nasal opening anticipate features of the Neanderthals, but its face is broader and flatter than in Neanderthals. Its cranial capacity (c. 1220 ml, 41 oz) sits on the margins between the erectus and Neanderthal ranges.
Also from around this time are fragmentary fossils from the site of Arago in the French Pyrenees. Some archaeologists believe that the inhabitants of Arago Cave were hunters of wild sheep, whose bones are also found at the site. Some fragments at Arago have been fitted together to reconstruct the face and right side of a skull that appears similar to the Petralona skull and is transitional between an erectus and a Neanderthal shape. A hip bone and other body bones confirm the trend from Boxgrove and the Sima, in which heidelbergensis has a very robust, yet modern-looking body.
It is worth pausing here to consider why the European heidelbergensis population was so large and muscular, with the bodies of boxers. One theory is that they had become specialized ambush hunters, using wooden spears in close combat against sizeable prey. This strategy contrasts with that of our own African ancestors, who had the ability to run down prey over long distances. Contemporary African hunter-gatherers have been observed using this hunting technique, in which hunters effectively out-endure prey, which eventually become tired and bewildered, making a kill relatively easy after a long run. Pursuit hunting can be effective in the hot African savannah, which is mostly flat and free of trees, but even in a partially forested and more temperate European river valley, it would not work. It is possible that this divergence in hunting strategies explains the difference in physique between Neanderthals and modern humans.
Following an extremely cold glaciation and during a long warm period called the Great Interglacial, we find a skull in Britain from 400,000 years ago that resembles the skulls of the Sima. A quarry near Swanscombe, England yielded three skull fragments which, despite being found in 1935, 1936 and 1955, belonged to the same individual. The Swanscombe skull has a little dimple, called a suprainiac fossa, at its base, and this feature is typical of Neanderthals; it probably has something to do with the way that strong neck muscles attached to the back of the skull. Unfortunately, the face of this skull has not been found, but we do know that the estimated brain size (1300 ml, 44 oz) was larger than that of the Petralona skull.
A skull from Steinheim, Germany, some 100,000 years after Swanscombe, challenges the notion of a smooth evolution from the earliest European heidelbergensis fossils to fully formed Neanderthals. Found in 1933, the Steinheim skull is smaller (1100 ml, 37 oz) than Swanscombe and Petralona, and its mode of ‘neanderthalization’ is reversed from the pattern at Petralona and the Sima, where Neanderthal traits appeared earlier in the front of the skull. With the caveat that the Steinheim skull is incompletely preserved and its front half is distorted, the back of the skull looks much more Neanderthal-like than the front.
Two sites roughly contemporary with Steinheim – Bilzingsleben, Germany, and Vértesszöllös, Hungary – provide a more profound challenge to the idea of a gradual, uniform evolution towards Neanderthal forms. At Bilzingsleben, remains of three human skulls were unearthed in the 1970s. At Vértesszöllös, a single skull fragment was discovered on 21 August 1965, the traditional ‘name day’ or religious festival day for the prophet Samuel, and this most ancient Hungarian was given the popular nickname Samu. Ian Tattersall has argued that skull fragments from these two sites do not seem to have any incipient Neanderthal traits at all and are associated with flake-based tools such as the Clactonian. Stringer believes that they are related to heidelbergensis, but describes them as more primitive.
Could it be that while part of the European heidelbergensis population was evolving into Neanderthals, another part was not? Or perhaps more archaic humans periodically entered Europe from Asia, as the local heidelbergensis people established their own evolutionary trajectory. This scenario may be supported by mitochondrial DNA evidence retrieved from human bones at Sima de los Huesos, linking that population with Denisovians in Asia. There is some poignancy in the thought that when fully for
med Neanderthals appeared some 250,000 years ago, they had recently out-competed a more archaic European population. If that is the case, then the Neanderthal story is framed by two encounters with other forms of human. In the first encounter, the Neanderthals emerged victorious as the sole occupier of Europe. In the second, they ceded the continent, and the planet, to us.
By 250,000 years ago, as the successful ‘handaxe people’ took on an increasingly Neanderthal-looking head shape, their stone tool technology became more advanced and they relied less on the bulky handaxe. It is at this moment that the Neanderthal story truly begins.
Reconstruction of a Neanderthal child based on the Devil’s Tower Gibraltar 2 remains excavated in 1926 by Dorothy Garrod, who also made important discoveries in northern Israel and Iraq. Reconstruction by Elisabeth Daynès.
Gorham’s Cave: this Neanderthal site is just across the sea from Morocco, where early modern humans were living around 130,000 years ago. This and other nearby sites have produced some of the latest dates for Neanderthals, although the dates are controversial.
‘Excalibur’, a handaxe found in the Sima de los Huesos, Atapuerca, Spain, knapped from reddish quartz, which is scarce in this area. This was the only artifact found in a deposit of some 6,500 human fossils, representing around thirty individuals, and the excavators believe it may have had symbolic meaning.
A juxtaposition of a Neanderthal skull from La Ferrassie, France (left), and a modern human skull from Cro-Magnon, France (right).
The Neanderthals Rediscovered: How Modern Science is Rewriting Their Story Page 6