Saturday, 21 February 2009

The Neanderthals

Of all early humans, none have captured the public imagination to anywhere near the extent of the Neanderthals. Indeed, with the possible exception of the dinosaurs, no extinct species is so deeply rooted in our popular culture. The idea that tens of thousands of years ago, people very much like ourselves shared the planet with another human species is one that intrigues many.

Although like “dinosaur”, the term “Neanderthal” is all-too-often used in a pejorative sense, in literature Neanderthals have generally been portrayed in a sympathetic light, for example The Inheritors by William Golding; Jean M. Auel’s Clan of the Cave Bear series; and The Ugly Little Boy by Isaac Asimov. The Neanderthal Parallax is an award-winning trilogy by Canadian SF writer Bob Sawyer about a team of scientists who accidentally make contact with a parallel universe in which the Neanderthals rather than Homo sapiens became the dominant life form on Earth.

Once thought of as a subspecies of Homo sapiens, genetic evidence now suggests that Neanderthals diverged from modern humans long before either species existed. Green et al (2006) give a date of 500,000 years ago. “Classic” Neanderthals emerged in Europe around 200,000 years ago (Cameron & Groves, 2004), by which time modern humans were emerging in Africa.

The term Neanderthal comes from Neander Thal (Neander Valley), near Dusseldorf, where the type specimen Neanderthal 1 was discovered at Feldhofer Cave in 1856. The German spelling was changed to Neander Tal in 1901, hence the commonly-used variant spelling Neandertal; however this usage is not acceptable for the scientific name Homo neanderthalensis, which was assigned before the change in spelling. Under rules of taxonomic nomenclature, once a name has been assigned, it cannot be changed.

The Neander Valley is named for Joachim Neumann, a 17th Century theologian who is usually referred to by the classicised form of his surname, Neander. He is best known for the hymn Praise to The Lord, The Almighty, the King of Creation.

The literal meaning of Neanderthal is therefore, rather ironically, New Man’s Valley.

Though the first fossil recognised as not representing a modern human Neanderthal 1 was not actually the first discovery of a Neanderthal. Specimens had previously been recovered in Ennis Cave, Belgium between 1829 and 1830 and Forbes Cave, Gibraltar in 1848; however their significance was not immediately recognised.

The Feldshofer Cave discovery comprises a skullcap and two femora, three bones from the right arm, two from the left arm, part of the left ilium, fragments of a scapula, and ribs. They were recovered by quarry workers in 1856. Unfortunately they may have inadvertently discarded further remains and other items that could well have included tools, and there is almost no record of context and associations (Klein, 1999). The find was examined by a local schoolteacher and amateur naturalist, Johann Karl Fuhlrott, who noted that the remains were unlike those of modern humans. Fuhlrott passed the remains on to Hermann Schaaffhausen, Professor of Anatomy at the University of Bonn. The pair jointly announced the discovery in 1857. However Schaaffhausen considered the Neanderthals to represent an ancient Northern European race predating the Germans and the Celts. That they might represent a new species of human was first suggested in 1864 by the Irish anatomist William King, who proposed the name Homo neanderthalensis. King’s suggestion was not widely accepted at first and, foreshadowing the debate over the Flores hominins almost a century and a half later, the Prussian pathologist Rudolf Virchow dismissed the Feldshofer remains as belonging to a modern human affected by disease.

Neanderthal 1 is now believed to be 40,000 years old (Scarre, 2005).

Key sites:
The Neanderthals are known from numerous sites in Eurasia ranging from the United Kingdom to the northwest, Uzbekistan to the east, Israel to the south, and Gibraltar to the southwest. These include:

Krapina, near Zagreb, Croatia. 120,000 years old. This large find comprises roughly 900 fragmentary remains representing from between 14 to as many as 82 individuals, discovered by Dragutin Gorjanović-Kramberger between 1899 and 1905.

La Chapelle-aux-Saints, France. La Chapelle-aux-Saints 1 is a partial skeleton, 50,000 - 60,000 years old.

Le Moustier, France. c. 40,000 years old. Le Moustier 1 young adult (partial skeleton); Le Moustier 2 child (partial skeleton). The Mousterian tool tradition, associated with the Neanderthals, is named for tools found at this site.

Kebara Cave, Mt Carmel, Israel. In 1983 an adult male skeleton (Kebara 2) was found. It is 50,000 - 55,000 years old and includes the most complete pelvis so far found. Kebara 1, an adult male, is also of significance, having provided the only known hyoid bone of a pre-modern human.

Tabun Cave, Mt Carmel, Israel. Tabun-C 1 is the almost complete 120,000 years skeleton of a Neanderthal woman.

Physical description:
The Neanderthal braincase is long and relatively low and is cylindrical when viewed from behind. The cranial capacity is between 1245-1740cc, averaging 1520cc, compared with 1560cc for an early modern human, or 1340cc for a present-day human. The frontal bone is low and receding, with continuous brow-ridges forming a double arch above the orbits. The face is long and prognathous and the chin is usually absent, with the cheekbones sloping backwards. The nasal aperture is broad, high and prominent.

Postcranial bones are robust and stout, the vertebral column heavily built, the ribcage large and wide, a long clavicle, large shoulder and elbow joints, short forearm, hands with strong grip and wide finger-tips, wide pelvis, longer and thinner pubis, thick-walled femur, short and thick-walled tibia, large ankle-joints and wide, strong toe bones. There are well-developed muscle markings throughout.

Neanderthals were 12 to 14 cm (4½-5½ in) shorter than modern humans. Based on 45 long bones from (at most) 14 males and 7 females, Neanderthal males averaged between 164 to 168 cm (5 ft 4½ in to 5 ft 6 in) and females 152 to 156 cm (5 ft to 5 ft 1½) tall (Helmuth, 1998). Their body weight has been estimated at 75kg on average, comparable to that of present-day humans (Cameron & Groves, 2004; Conroy, 1997; Klein, 1999).

To sum up, Neanderthals were powerfully built, far more so than early modern humans, even though the latter were more robust than present-day humans. As Conroy (1997) points out, Neanderthals probably didn’t do limp-wristed hand-shakes!

Adaptations of the Neanderthals:
The limb proportions of the Neanderthals were probably adaptations to living in cold places, and are mirrored to some extent by those of present-day Inuit and Sami people. The Neanderthals were however more extreme in their limb proportions, despite probably living in more moderate conditions. This suggests they were more reliant on their physiology to combat the cold than any modern human (Klein, 1999).

The robust (thick-walled) limbs and large bodies suggest physical stress was a part of their everyday life. (Scarre, 2005). The upper limbs may have been adapted to heavy foraging such as spear thrusting while the lower limbs are those of long-range bipeds (Cameron & Groves, 2004).

The large nasal aperture and sinus tracts may have been maximised to warm and moisten the dry, cold tundra air (Scarre, 2005).

Facial development and powerful jaws may have reflected the use of teeth as a vice-like tool, possibly for gripping mammal hides while skinning them with stone tools. Wear on teeth consistent with this hypothesis (Cameron & Groves, 2004; Scarre, 2005).

It has been suggested that many distinctive Neanderthal features resulted from genetic drift (random change) in a population that was isolated in Europe for much of its history, rather than the traditional explanation of natural selection. This is suggested by the way Neanderthal-like features seem to have accreted in pre-Neanderthal hominins and supported by a recent study, which obtained the divergence time for Neanderthals from modern humans based on statistical comparisons of cranial metrics and obtained a mean figure of 373,000 years, close to figures based on comparisons of DNA sequences. This implies that the cranial and DNA sequence data largely reflects neutral mutational divergence, causing it to track population history rather than the effects of natural selection (Weaver et al, 2008).

Gestation period of the Neanderthals:
In 1984, Erik Trinkaus noticed that the superior pubic ramus of the Neanderthal pelvis seemed to be longer than that of a modern human, indicating a wider birth canal. This he claimed implied that the gestation period of Neanderthals was longer than that of modern humans, possibly as long as a year (Trinkaus, 1984). Other theories were proposed to explain the difference: that it simply reflected the greater size of the head in comparison to the relatively short stature (Rosenberg, 1985); or that the brain grew faster in utero compared with modern humans (Dean et al, 1986).

In 1987 an analysis of the Kebara 2 pelvis was published (Rak & Arensburg, 1987) which showed that the pelvic inlet was comparable to that of a modern human and that the length of the superior pubic ramus was due to a more externally rotated hip bone. This suggested that the unique features of the Neanderthal pelvis might be due to locomotion and posture-related biomechanics rather than the need for an enlarged birth canal.

Neanderthals skin and hair colour:
A study has recently been carried out of the melanocortin 1 receptor (mc1r) gene in Neanderthals. This gene is responsible for skin and hair colour variation in humans. Variants of mc1r with reduced function give rise to pale skin and red hair. DNA was extracted from two Neanderthal fossils, Monti Lessini (Italy) and El Sidrón 1252 (Spain). A mutation of the gene, known as R307G, was found. This mutation is not present in modern humans. The gene was then expressed in COS-7 cells (a cell culture derived from vervet monkeys often used in biomolecular research). The results suggested that the R307G allele had reduced function. This does not confirm that the two individuals tested – much less all Neanderthals – had red hair and pale skin, but it is more likely if they were homozygous or compound heterozygous for this allele. Whether this was the case for these two Neanderthals was not determined by the study (Lalueza-Fox et al, 2007).

Evolutionary history:
It is now generally accepted that the Neanderthals were a separate species to Homo sapiens and not a subspecies; nor does it now seem likely that modern Europeans are descended from Neanderthals. Rather it would appear that the two lineages diverged around 500,000 years ago (based on genetic evidence) or possibly later, around 370,000 years ago (based on cranial data).

In a 2002 study, Yoel Rak of the Tel Aviv University demonstrated that the specialized Neanderthal mandibular ramus (lower jawbone) morphology is an element in a complex of derived morphologies of the mandible and face that are unique to the Neanderthals and the corresponding features in modern humans are actually primitive retentions from Homo erectus. This provides further support for the contention that Neanderthals are not ancestral to modern humans (Rak et al, 2002).

Homo antecessor, known from the Atapuerca Hills of northern Spain, has been touted as a possible ancestor. These hominins lived 700,000 – 800,000 years ago, but even assuming it is a valid species at all it seems more likely to have been an offshoot of Homo ergaster that died off without issue, possibly during the glacial periods of 600,000 – 800,000 years ago.

The probable common ancestor is Homo heidelbergensis. Neanderthal-like features seem to have accreted in the European deme of this species; for example the Steinheim skull from Stuttgart, Germany; the Sima de los Huesos specimens from Atapuerca in northern Spain and the Swanscombe cranium from the UK.

Cameron & Groves (2004) cautiously accept these hominins as a distinct species, Homo steinheimensis, but argue that they are really primitive Neanderthals. At all events they are clearly intermediate between Homo heidelbergensis and “classic” Neanderthals. “Incipient Neanderthal features” include the configuration of the supraorbital tori, the large size of the nasal openings, the medial projection from the side walls of the nasal cavity, developed occipital torus and suprainiac depression and a long cranium with a slightly more elevated frontal bone (Cameron & Groves, 2004).

Not all these features are seen in every specimen; different features appeared at different times in different populations. Some are more Neanderthal-like in the face; others in the braincase. This does suggest that the distinctive Neanderthal craniofacial complex evolved as a series of disconnected features, in turn supporting the view that Neanderthal morphology was more a product of a series of neutral mutations (genetic drift) than natural selection (see above).

The “classic” Neanderthals had emerged in Europe by 200,000 years ago. The Neanderthals from Western Asia and the Levant were probably an expansion of the European population.

The Mousterian industry:
The Neanderthals are generally associated with the Mode 3 Technology or Mousterian industry, named for the type site, Le Moustier, a rock shelter in the Dordogne region in the south of France. However this technology is also associated with early modern humans; conversely later Neanderthals have been associated with more advanced tool kits.

The Mousterian tools are considerably more sophisticated than those employed by either Homo heidelbergensis or the “ante-Neanderthal” Homo steinheimensis. The Mousterian industry is basically a stone core technology in which the core is pre-shaped to facilitate the striking off of flakes of a desired shape, which in turn can be retouched to provide a continuous cutting edge.

The pre-shaped cores are known as Levallois cores, after a site at Levallois-Perret, in the north-western suburbs of Paris, where examples have been known since the 19th Century. A number of Levallois flaking techniques appear to have been employed, allowing a degree of control to be exercised over the shape and size of the resulting flakes. The tools were fashioned for specific purposes, unlike the preceding Acheulian multi-purpose artefacts. Considerable planning, involving at least six separate stages, went into their production. The lithic technology of the Neanderthals appears have been very flexible, with different solutions reflecting the size, shape and quality of available materials.

In the 1950s and early 1960s, François Bordes (1919-1981), a leading figure in French Palaeolithic archaeology, formalised a typology that recognised a total of 63 different tool types in three classes: sidescrapers, retouched points and denticulates (toothed pieces). A sidescraper was defined as a flake on which one or more edges bear smooth, continuous retouch; a point as a flake on which two continuously-retouched edges converged directly opposite the butt; and a denticulate as flake that was retouched to produce a toothed edge. A denticulate with only one indentation was designated a notch.

In addition, the overall Mousterian was divided into five groups or facies: the Mousterian of Acheulian Tradition (MAT) A and B, Typical Mousterian, Denticulate Mousterian and Charentian. The groups were assigned on the basis of varying frequency of tool types such as hand axes, scrapers, points, etc. Thus MAT A & B were characterised by abundant hand-axes, which are rare or absent in the other groups; Typical Mousterian was dominated by sidescrapers; Denticulate Mousterian by denticulates and notches, etc.

Bordes believed that his five groups were cultural in nature, representing different contemporary ethnic groups or tribes in Middle Palaeolithic society.

That Bordes’ scheme represents the reality of the Mousterian industry is questionable as tool types often grade into one another and may well represent re-sharpening of a smaller number of basic forms – i.e. what Bordes saw as several distinct types may represent a single tool type at different stages of its life before being finally discarded. The extent to which tools were refurbished during their life would in turn have depended on the quality of available raw materials; if these were scarce, existing tools would have had to be retained longer. Also if a particular site remained in use for a long time, its occupants appear to have been more prone to re-use and modify the tools already at hand.

In addition, some assemblages excavated after Bordes defined his facies clearly fall between the variants as proposed, suggesting that inter-assemblage variation is continuous rather than discreet. Lewis and Sally Binford have suggested that this variation was functional and related to the performance of various tasks. For them, the differing assemblages simply reflected differing tasks carried out by the same people, either at different sites, or at the same site at different times, possibly different seasons.

Finally it is now clear that the use to which the Mousterian stone artefacts were actually put does not in general correspond to the names assigned to them. Microwear analysis suggests that while the denticulates and notches were largely used to work wood, the sidescrapers and points were used to work a greater variety of materials including wood, meat, bone and animal hide. The latter show evidence of hafting to wooden handles and – though only in the case of points recovered from sites in Israel – to wooden spear shafts.

The Châtelperronian industry:
The Châtelperronian industry, known from central and south western France and Northern Spain also appears to be associated with the Neanderthals, whose remains rather than those of modern humans have been found at sites such as the Grotte du Renne at Arcy-sur-Cure and Saint Césaire. The industry is named for the type site of la Grotte des Fées, in Châtelperron, Allier, France and probably began around 45,000 years ago, persisting until 36,000 years ago. The stone artefact assemblages generally combine typical Mousterian stone tools with articles more typical of the Upper Palaeolithic such as endscrapers and burins, bone tools and personal ornaments. At the Arcy site, Châtelperronian articles included bone implements that appeared to have been decorated and animal teeth, pieces of ivory, bone and shells that were pierced or grooved for use as beads or pendants. Furthermore the living space has been modified to an extent common only in the Upper Palaeolithic, with traces of hut emplacements including a circle of 11 postholes possibly supporting mammoth tusks and enclosing an area of 3 to 4 sq. metres, which was paved with limestone plaques.

The Châtelperronian people, in short, show evidence of modern human behaviour, but whether this was of independent Neanderthal origin or simply borrowed from neighbouring Cro-Magnon (i.e. modern) humans associated with the Aurignacian culture remains contentious. João Zilhão, Francesco d’Errico argue for independent origin (Zilhão et al, 2006) but Richard Klein claims that the most persuasive Upper Palaeolithic elements of the Châtelperronian only appear towards its end, suggesting acculturisation from the Cro-Magnon people (Klein & Edgar, 2002). Steven Mithen has stated that the coincidence of the Neanderthals coming up with the use of beads just before modern humans appeared wearing them is “just too great to be believed” (Mithen, 2005).

It is widely believed that the Neanderthals intentionally buried their dead, with evidence of Neanderthal burials known from Shanidar Cave in northern Iraq and from a number of sites in France.

The Shanidar site was excavated between 1953 and 1960 by Ralph Solecki, who recovered the remains of nine Neanderthal individuals comprising two groups. One group dated to around 60,000 years ago and the other to 70,000 – 80,000 years ago. Some individuals appeared to have been killed by a cave-in, but others had been intentionally buried. One individual, Shanidar 4 was supposedly found in association with pollen, suggesting flowers had been used in the burial, but the pollen could well be contamination introduced during the excavation of the site.

Another individual, Shanidar 1, an elderly male victim of the cave-in, showed evidence of numerous injuries. That bone-healing had occurred implied that they had been sustained before his death. In turn, this suggests that other members of his group must have cared for him during periods of convalescence.

In France, burials are known at La Chapelle-aux-Saints (another elderly male, see above); Le Moustier (a young adult, see above); Regourdou (one individual in a stone-lined pit) and La Ferrassie. The latter site appears to be a Neanderthal cemetery in which seven individuals had been buried. There were two adults and five children, suggesting a family plot. The site may be 70,000 years old.

Although none of these sites show conclusive evidence of grave goods, the purpose of the burials must have been more than simply disposing of dead bodies, as there are far simpler ways of achieving this. Even if the Neanderthals lacked symbolic behaviour, in my view there is no reason to suppose that they felt the loss of kin or friends any less keenly than do modern people.

Neanderthal patterns of land use differ from those of bother earlier and modern humans. Site usage is well-documented from France and Spain. In south-western France, cave and rock shelter sites share certain features:
1. Well-sheltered locations in positions offering extensive and wide-ranging views over ecologically-diverse adjacent valley habitats.
2. Easy access to abundant and high-quality raw materials.
3. Sites located to serve as central places from which diverse economic and technical activities could be connected.

Open-air sites are typically located on higher, more exposed locations, usually on major plateaus, close to springs, streams or lakes (Cameron & Groves, 2004).

The caves and rock shelters were probably living places rather than places for killing animals and butchery. Stacked hearths evidence repeated fire building over thousands of years. The fires would have been used for cooking food and to provide warmth, light and protection from predators. Though some hearths were underlain by rocks, they are generally fairly unsophisticated. A similar pattern is seen at African Middle Stone Age sites, which were occupied by early modern humans. There is a sharp contrast with the later hearths of modern humans in the Upper Palaeolithic. These were fitted with stone liners, air-intake ditches and other features to control airflow and heat dissipation.

The open-air sites are harder to interpret. Some are near sources of stone raw materials and have extensive flaking debris – clearly these sites were used as stone tool workshops. But generally preservation of the evidence at these sites has not been sufficient to distinguish between possible usage as campsites or as killing and butchery sites.

Generally these sites and the contemporary MSA sites in Africa show very little signs of modification, other than hearths. This is again in contrast to the extensive architecture seen at later Upper Palaeolithic sites, which include stone walls, pavements and pits.

It has been shown that where stone sources at Neanderthal and African MSA sites have been established, they have turned out to be largely local, with less than 5% having come from more than 30km away. Again, there is a sharp contrast with the Upper Palaeolithic, where evidence exists of around 20-25% of stone having been obtained from distances greater than 30km.

The inferences are that in the Upper Palaeolithic, modern humans controlled larger territories than either their earlier brethren in Africa or the Neanderthals; or that they had more extensive trade networks than either of these. (Klein 1999).

Food-gathering strategies:
Isotopic analysis of Neanderthal bones suggests that up to 90% of their protein intake came from meat. Some of this may have been scavenged, but there is evidence for the hunting of medium sized and even large carnivores. A wooden spear with a fire-hardened tip was found lodged between the ribs of a mammoth at a 130,000 year old site in Germany. At La Cotte de St. Brelade, a cave site in Jersey (then part of mainland Europe), there is evidence of mass slaughter, where animals were stampeded over the edge of cliffs, butchered and dragged into the cave for consumption. The Neanderthals also ate any available small animals including tortoises, turtles, rabbits and shellfish (Cameron & Groves, 2004; Scarre, 2005).

Language and Behavioural modernity:
Anthropologists define modern human behaviour as the use of abstract thought, symbolic behaviour (such as art and creative expression), use of syntactically-complex language and the ability to plan ahead.

The following are generally accepted as evidence of modern human behaviour:

1. Finely made tools.
2. Fishing.
3. Evidence of long-distance trade among groups.
4. Use of pigment and jewellery for decoration or self-ornamentation.
5. Figurative art, such as cave paintings, petroglyphs and figurines.
6. Burial of the dead.
7. Systematic use of space in living-areas, with particular areas reserved for particular functions, e.g. food storage.

There are two main views for the origins of modern human behaviour. The ‘‘Great Leap Forward” model attributes the sudden appearance of symbolic artefacts to a “big bang” of human consciousness triggered by a genetic mutation, 50,000 years ago, long after the appearance of the first anatomically-modern humans, who may have lived as long as 195,000 years ago (Omo Kibish 1 and 2, Ethiopia) or at least 154,000-160,000 years ago (Herto Bouri, Ethiopia). On this model, modern human behaviour is restricted to anatomically modern humans who lived after 50,000 years ago. This view is supported by many authorities including Jared Diamond, Steven Mithen and Richard Klein (see Diamond, 1991; Mithen, 1996 & 2005; Klein & Edgar, 2002).

A key question is did Neanderthals possess the same linguistic abilities as modern humans. As noted above, this is crucial to the question of their behavioural modernity. The hyoid bone from the Kebara I skeleton (see above) is more-or-less identical to that of a modern human. The hyoid bone is attached to the cartilage in the larynx and anchors the muscles required for speech. The Neanderthal larynx itself is now believed to be positioned low in the throat, like that of a modern human. Earlier claims that the Neanderthal larynx was positioned high in the throat, like a chimpanzee (or a modern human baby) are now known to be incorrect; they were based on the Neanderthal specimen from La Chapelle-aux-Saints, which is now known to be too badly distorted and incomplete for a proper reconstruction.

The hyperglossal canal, which carries nerves from the brain to the tongue, is the same width as that of modern humans, suggesting the same degree of enervation; but those of earlier hominins are more comparable to those of present-day apes. Also comparable is the nerve-carrying canal controlling the diaphragm and hence breathing. While this latter feature could relate to running, etc, it can also be used to provide the level of fine breathing control required for speech.

All in all, then, the Neanderthals appear to have had all the anatomical features required for speech. But did they possess the cognitive ability to handle syntactically-complex language?

No, says Richard Klein, a leading proponent of the Great Leap Forward theory. Klein’s original “prime suspect” for the genetic mutation leading to modern human behaviour was a gene known as FOXP2, or forkhead box P2, which regulates a number of other genes, some of which are believed to play a role in the development of the parts of the brain associated with speech, although the exact genes involved are not known. The FOXP2 gene is not unique to humans, but exists with very few differences in other animals.

The first clue that FOXP2 might be a “speech gene” came from studies of Family KE, an extended British family living in London (their actual identity is not in the public domain). Some members of the family have problems with aspects of grammar, including the use of inflexions for marking tense. They also have difficulty in producing the fine movements of the tongue and lips required for normal speech. The problem affects three generations of the family and has been studied since the 1990s. In 2001 geneticists determined that the affected members of the family all have a defective version of the FOXP2 gene.

In 2002 a team led by Wolfgang Enard at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany compared the human version of the FOXP2 gene with that of the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse. They found that the gene is highly conserved, with differences of just three amino acid positions out of around 700 between the human version and the mouse version. But curiously two of these changes had occurred since the split between humans and chimps, a far more recent occurrence than the split between humans and mice. They suggested that these two changes might be critical to speech and language. The beneficial mutation has been positively selected for by natural selection and they estimated that it had become fixed in the human population at some stage in the last 200,000 years (Enard et al, 2002).

Klein believed the actual date would be 50,000 years, and that FOXP2 was the “smoking gun” responsible for the Great Leap Forward. But even a date of 200,000 years would rule out behavioural modernity in the Neanderthals, who had diverged from Homo sapiens much earlier.

Then in 2007 came a complete volte-face from the Max Planck Institute. The sequencing of the Neanderthal genome had revealed that Neanderthals possessed exactly the same version of FOXP2 as do modern humans (Krause et al, 2007). This not only pulled the rug from under Klein’s argument, it was also rather embarrassing for the group whose earlier 200,000 year estimate was now seen to be off by a factor of at least two. Dr. Svante Paabo, who was involved with both studies, admitted that the earlier estimates were “not flawed but rely on assumptions that are necessary but also universally known to be oversimplifications of the reality”.

Steven Mithen, Professor of Archaeology at Reading University, believes that the Neanderthals lacked what he refers to as “cognitive fluidity”.

In a theory first proposed in his 1996 book “The Prehistory of the Mind”, Mithen claims that the human brain originally had separate cognitive “domains” for different functions, such as social interaction, tool-making, food and resource gathering (“natural history”), etc. Modern human behaviour came about when the barriers between these domains broke down, allowing them to interact with each other. Art, religion and language all arose from the synergistic interactions between the various domains, but the Neanderthals quite literally never made the connection.

Mithen draws heavily on the work of Jerry Fodor, Annette Karmiloff-Smith, Michael Tomasello, Howard Gardiner, Leda Cosmides and John Tooby, but the idea of initially separate domains interacting may have been inspired in part by Julian Jaynes’ controversial theory about “bicameral minds”, proposed in 1976. However Mithen does not mention Jaynes’ theory (See Mithen, 1996; Fodor, 1983; Karmiloff-Smith, 1992; Tomasello, 1999; Gardiner, 1983 & 1999; Jaynes, 1976).

In 2005, in a book entitled “The Singing Neanderthal”, Mithen proposed the Neanderthals used a form of communication he refers to as Holistic, manipulative, multi-modal, musical and mimetic – abbreviated to Hmmmmm – which had features of both language and music. Instead of combining words to make up a range of meanings, Neanderthals and other archaic humans communicated with "holistic" utterances, which conveyed complete messages. While non-human primates use similar utterances to communicate information to others of their kind, the Neanderthals used them to manipulate the behaviour of others. While more complex than non-human primate communications, Hmmmm was very different to modern speech. Song, dance and mime made up the repertoire and while simpler forms of Hmmmmm were employed by earlier humans, it was taken onto a new level by the Neanderthals.

In the same work, Mithen argues strongly against behavioural modernity for the Neanderthals. This, he says, is evidenced by the “immense stability of their culture”, which endured with little change for over 200,000 years. Had they possessed language, it would have been impossible for their culture to have remained so stable and so “limited in scope”. Their lack of innovation was to be their undoing because “if there was ever a population of humans that needed to invent bows and arrows, the means for storing food, needles and thread, and so forth, it was the Neanderthals” for whom life was consequently so harsh that few lived beyond 35, leaving their populations only marginally viable (Mithen, 2005).

Richard Klein is even more damning of the Neanderthals: “It is not difficult to see why the Neanderthals failed to survive after behaviourally modern humans appeared. The archaeological record shows that in virtually every detectable aspect – artefacts, site modification, ability to adapt to extreme environments, subsistence, and so forth – the Neanderthals were behaviourally inferior to their modern successors, and to judge from their distinctive morphology, this behavioural inferiority may have been rooted in their biological makeup” (Klein, 1999).

But not everybody accepts the Great Leap Forward model or the behavioural inferiority of the Neanderthals. Such views are disputed among others by Stephen Oppenheimer, Robert Foley, Sally McBrearty and Alison S. Brooks, who claim there was no “big bang” and knowledge, skills and culture gradually developed over hundreds of millennia (see Oppenheimer, 2003; Lewin & Foley, 2004; McBrearty & Brooks, 2000). On this view, the technological differences between the Neanderthals and Cro-Magnons were cultural rather biological. The blade-based Mode IV tool technology of the latter, while superior to the Neanderthals’ Mousterian technology, did not require genetic mutation - anymore than writing genes, aeroplane genes and internet genes were required for these things to become possible.

Did Neanderthals and modern humans interbreed?
This is a topic of perennial interest, but conclusive evidence one way or the other is lacking. Although Neanderthals and modern humans both occupied sites in the Levant from 100,000 years ago, the two species were never present at the same time and the first contact between them may well not have occurred until modern humans first entered Europe, possibly 45,000 years ago according to a recent study (Anikovich et al, 2007).

There is little doubt in my mind that modern humans did on occasions have sex with Neanderthals. Even in the wild, closely-related species will on occasion mate, for example horses and donkeys, lions and tigers, and whales and dolphins. Such matings do lead to offspring and while these are generally infertile, they are usually viable. Given that modern humans will have sex with sheep, it seems inconceivable that they did not at some stage do so with Neanderthals. While Neanderthals would certainly have appeared strange to the incoming modern humans and vice-versa, they would not necessarily have seemed unattractive to each other. For a present-day human though, having sex with a Neanderthal might be a somewhat hazardous affair, given the considerably superior physical strength of the latter; but to the more robust Cro-Magnons this might have been less of an issue.

Could such unions have resulted in fertile offspring, or indeed any offspring? Given that we now know that there were probably no significant obstetric incompatibilities (see above) it does not seem unreasonable to suppose that hybridisation was possible, as with other closely-related species. But no convincing fossil evidence of Neanderthal/modern human hybridization has ever come to light, suggesting that it was rare if indeed it happened at all.

Claims that the 24,500 year old skeleton of a 4-year-old child found at Abrigo do Lagar Velho, Portugal in 1998 is an example of a hybrid (Duarte et al, 1999) are not widely accepted. Most researchers think that the Abrigo do Lagar Velho child simply was either an unusually stocky modern human child or one with a growth abnormality.

A 2006 study suggested that an adaptive allele (i.e. an advantageous version of a particular gene) of microcephalin (MCPH1), a gene linked with brain size, introgressed into modern humans from an extinct human lineage, quite possibly the Neanderthals (Evans et al, 2006). Haplogroup D as this version is known first appeared 37,000 years ago, closely corresponding to when modern humans began to colonise Europe. It is now the most common form throughout the world, except for in sub-Saharan Africa. The study suggested that its appearance might have resulted from cross-breeding between modern humans and Neanderthals. However this has now been ruled out following the publication of the first draft of the Neanderthal genome by a team led by Svante Paabo of the Max Planck Institute in Germany. The Neanderthal version of the microcephalin gene turns out to be the ancestral form found today in African populations.

Paabo has said that it seems overall Neanderthals have contributed, at most, a "very limited" fraction of the genetic variation found in contemporary human populations (quoted on BBC website, 12 Feb 2009).

Chris Stringer of the Natural History Museum in London believes that while interbreeding was most likely possible, it happened only rarely, with trivial impact on modern humans (quoted on BBC website, 12 Feb 2009).

The fate of the Neanderthals:
The most recent Neanderthal fossils are those from Gorham’s Cave, Gibraltar, suggesting that they occupied the cave until 28,000 years ago and possibly until as recently as 24,000 years ago (Finlayson et al, 2006). Modern humans may have first entered Europe 45,000 years ago, with Upper Palaeolithic sites on the Don River in Russia dating back to that time. Thereafter they spread rapidly across western and central Europe 42,000-40,000 years ago (Anikovich et al, 2007). Although there was certainly a long overlap before the Neanderthals finally disappeared, inevitably Homo sapiens has been widely blamed for their demise.

In his book Before the Dawn, published in 2007, Nicholas Wade refers to “the long struggle against the Neanderthals” and Stephen Oppenheimer suggests there was a “long and probably unfriendly stalemate” between the two species (Wade, 2007; Oppenheimer, 2003).

But the reality is that there is not a single piece of evidence for direct conflict between modern humans and the Neanderthals; nor indeed is there evidence of intercommunity violence between Cro-Magnon groups. While absence of evidence is not the same thing as evidence of absence, it does suggest that such events were not particularly common. Even if relations between the two species were consistently unfriendly, there is certainly no possibility that the Neanderthals were the victims of genocide. The kind of systematic slaughter that cost countless millions their lives during the last century was the work of state-level societies, not hunter-gatherer tribes.

On the other hand, if we reject an independent Neanderthal origin for the Châtelperronian industry (and it is hard to argue with Steven Mithen’s view about the improbable coincidence of this being so), then it implies at least a degree of cultural contact between Neanderthals and Cro-Magnons and that there must have been some co-operation between the two species.

When Europeans first began to exploit the New World, the infectious diseases they brought with them proved catastrophic to the indigenous people, who had no immunity to smallpox, typhus, cholera and measles. It has been suggested that the Neanderthals similarly fell victim to diseases to which the Cro-Magnons had long since become immune. But this seems improbable as pandemic-causing diseases require dense populations to be viable and did not arise in human populations until the emergence of urban societies. In addition many diseases have arisen in human populations by crossing the species gap from animals, something that would have been rare if not impossible in pre-agricultural times.

It seems more likely that regardless of whether or not the Neanderthals were behaviourally modern, the superior technology of the Cro-Magnons gave the latter the competitive edge in the constant quest for the next meal, for shelter and for other resources in Ice Age Europe. If this resulted in only a slight breeding advantage for the Cro-Magnons at the expense of the Neanderthals, then within a few thousand years the latter would have become extinct.

Climatic instability over the middle part of the last Ice Age may have exacerbated the Neanderthals problems, though as a recent study has shown, tying their final demise to specific climatic events is problematic, due to uncertainty in dating. The date of 28,000 years for the final Neanderthal occupation of Gorham’s Cave does not coincide with a period of unduly harsh conditions, but if the more recent date of 24,000 years ago is accepted, then this would correspond to a time of deteriorating conditions at the onset of the Last Glacial Maximum, which reached its maximum extent 20,000 years ago. Competition with the Cro-Magnons would have intensified as the latter migrated south from the higher latitudes (Tzedakis et al, 2007).

Regardless of the exact role played by the Cro-Magnons, the Neanderthals would have found themselves becoming increasingly marginalised, pushed to the peripheries of Europe. 10-20,000 years might seem like a long time, but this final chapter of the Neanderthal story accounts for no more than ten percent of their career; at the end of which they were gone forever.


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© Christopher Seddon 2009

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