July 22, 2009

Did Homo sapiens kill Shanidar 3?

The evidence suggests that modern humans were responsible for this Paleolithic murder mystery, although it's not one of those cases were the evidence is strong enough to "stand up in court", so to speak.

I think that if modern humans and Neandertals ever crossed paths -- and the evidence is very clear that they were very close to each other, at least in Europe -- then inter-species violence is almost a given. Humans have been known to kill all sorts of animals, including members of their own species, so it would have been really difficult to imagine them not killing Neanderthals, if given the opportunity.

But, occasional conflict is not the same as annihilation. So, even if Shanidar 3 did die of a modern human hand, the conclusion is far from certain that Neanderthals as a species did.

Elsewhere on the web: MSNBC, Science Daily.

John Hawks has a thorough review:
Plugging into Bayes' theorem, that means that an encounter rate of 1 modern human for every 28 Neandertals would yield a five percent chance that a modern human was the culprit. Did Shanidar 3 encounter one modern human for every 28 of his own? If not, we have to conclude its very unlikely -- less than five percent -- that his wounds were caused by a modern human.
Arriving at a probability relies at many guesstimates of parameters; this is why I said that the authors' case wouldn't stand up in court. One of Prof. Hawks's hypotheses is:
We don't know the probability that Shanidar 3 encountered modern humans. We'll assume that Shanidar 3 would have been attacked with equal probability by whomever he encountered.
This hypothesis is probably as good as any, but the actual probability could very well be either higher or lower. For example, in a first contact scenario, within-group violence might decline in the face of a common "Other". A classical example is the temporary banding together of Greeks in the face of advancing Persians. While Greeks had a good chance of killing each other before and after the early 5th c. BC, the inter-Greek violence probability experienced a dip in order to face the Persian danger.

In a long-term cohabitation scenario, we might be tempted to assign slightly higher probability to inter-group than to intra-group violence. But this is far from a certain conclusion, since groups may differ in their average tendency to violence. Members of the more violent group may actually have a higher probability of being attacked by one of their own than by a member of a more peaceful group: put 100 mercenaries and 100 Buddhist monks together, and each mercenary will have a higher probability of being attacked by another mercenary than by a monk.

Were modern humans and Neandertals different in their tendency to violence? Did modern human succeed so well because they expanded peacefully and weren't held back by constant bickering? Or did their expansion result from them being warlike and prone to arguments and divisions that eventually led some of them to the ends of the earth? Perhaps, by a careful counting of spear points and traumas, we will, one day, be able to answer that question.

Journal of Human Evolution doi:10.1016/j.jhevol.2009.05.010

Shanidar 3 Neandertal rib puncture wound and paleolithic weaponry

Steven E. Churchill et al.


Since its discovery and initial description in the 1960s, the penetrating lesion to the left ninth rib of the Shanidar 3 Neandertal has been a focus for discussion about interpersonal violence and weapon technology in the Middle Paleolithic. Recent experimental studies using lithic points on animal targets suggest that aspects of weapon system dynamics can be inferred from the form of the bony lesions they produce. Thus, to better understand the circumstances surrounding the traumatic injury suffered by Shanidar 3, we conducted controlled stabbing experiments with replicas of Mousterian and Levallois points directed against the thoraces of pig carcasses. Stabs were conducted under both high and low kinetic energy conditions, in an effort to replicate the usual impact forces associated with thrusting spear vs. long-range projectile weapon systems, respectively.

Analysis of the lesions produced in the pig ribs, along with examination of goat ribs subjected primarily to high kinetic energy stabs from an independent experiment, revealed consistent differences in damage patterns between the two conditions. In the case of Shanidar 3, the lack of major involvement of more than one rib, the lack of fracturing of the affected and adjacent ribs, and the lack of bony defects associated with the lesion (such as wastage, hinging, and radiating fracture lines) suggests that the weapon that wounded him was carrying relatively low kinetic energy.

While accidental injury or attack with a thrusting spear or knife cannot absolutely be ruled out, the position, angulation, and morphology of the lesion is most consistent with injury by a low-mass, low-kinetic energy projectile weapon. Given the potential temporal overlap of Shanidar 3 with early modern humans in western Asia, and the possibility that the latter were armed with projectile weapon systems, this case carries more than simple paleoforensic interest.


1 comment:

Ponto said...

It may just be a matter of one species out competing the other for food sources and shelter or simply making better use of the available resources. Why the concentration on warfare? Life was hard in those ancient times. Lots of people sustained injuries. In modern times think the number of accidents caused by motor cars and machinery which have nothing to do with warfare. Accidents happen, with or without knifes or flying projectiles.

What about the mystery? The mystery as to the disappearance of modern humans in the Middle East and the replacement by Neanderthal like humans 100 to 70 kya? I suppose it was warfare! And the Neanderthals won.