Was Homo Heidelbergensis right-handed?
Excavations in China have uncovered bones of Homo Erectus, one of the ancestors of Homo Sapiens - that is, you and me. Allegedly a different species (although an ancestor), Homo Erectus is thought to have been a low-browed semi-ape, so it comes as a bit of a shock to hear the Chinese openly claiming that they are the descendants of Erectus and have nothing to do with Sapiens. I always knew the Chinese were different ...
Mind you, considering the number of happy and successful (as well as productive!) marriages between Europeans and Chinese, despite the claim of millions of years of separate development, I guess the "species" can't have been all that different. Perhaps Erectus was just as human as the rest of us?
Meanwhile another early human species is also proving to be rather more human than previously thought. According to the scientists, humans are the only species that shows a marked preference for one hand over another - the majority of us are right-handed; a few, like my wife, are left-handed. Handedness is considered to be one of the defining marks of being human because it is linked to the lateralisation of our brains and that in turn is linked to such skills as language and technology. In other words, if you were right- or left-handed, you were also likely to be able to talk and reason.
Marina Mosquera, a paleoantrhopologist at the Universitat Rovira i Rirgili in Tarragona, Spain, has been leading a team that has looked for clues to the earliest development of handedness. They first looked at tools created by early man for evidence whether they were created or used by people who favoured one hand over another, but whereas trying to use left-handed scissors in your right hand feels awkward, it is hard to tell the difference between a left-handed flint knife and a right-handed one!
Examinations of the interior of ancient skulls has proved similarly inconclusive. Evidence that the brain was split into two hemispheres is not only scant but in itself does not prove that the vital lateralisation has taken place.
However while examining the skulls Mosquera's team noticed scratch marks on the teeth of skulls belonging to Homo Heidelbergensis, an alleged ancestor of the Neanderthals. They seemed too deep to be merely normal wear and tear, yet they were not regular enough to be deliberate - some form of decoration or tribal identity markers. Mosquera doesn't reveal who got the bright idea, but someone came up with the thought that ancient man might have used his teeth as a third hand.
The suggestion is that Heidelbergensis held a piece of meat in one hand, put the other end in his mouth and held it with his teeth, then sawed away at it with a flint blade in the other hand. Occasionally he sawed too close to his mouth, the blade slipped and he scratched his teeth. I suggest that he would only have done this once, however: a slippage that left score marks on the teeth would certainly have gashed the lips and possibly gums as well and no one who has been to the dentist welcomes a return trip!
Mosquera got members of her team, which included a left-hander, to experiment using knives, meat and mouth guards (why she didn't just use plasticine and blunt knives I don't know!) The results were clear evidence that right-handed people would have left score marks slanting in one direction while south-paws left marks slanting in the opposite direction.
With the experimental evidence in, Mosquera turned to examining the physical evidence - 163 teeth found in the Sima de los Huesos cave in northern Spain. Presumably the Germans were hogging the beaches and leaving their towels on poolside sun loungers even back then! Of the 19 individuals represented by those teeth, Mosquera concluded that 15 were right-handed. The remaining four had vertical marks on their teeth which might have indicated left-handedness but were not conclusive evidence of it.
"Finding that a hominin species as old as Homo heidelbergensis is already right-handed helps to trace back the chain of modernity concerning hand laterality," Marina Mosquera concludes.
Of course the artists who draw pictures of these primitive ancestors of Homo Sapiens turn out depictions of hairy, knock-kneed creatures that would send any of us running for the trees - though if they were as ape-like as the artists claim, the trees would probably not have provided much of a refuge. It is interesting to compare some of the wild fantasies such as these early depictions of Neanderthals
with the reconstruction made by Dr Edward Rubin based on his study of the Neanderthal genome. This little girl could be the girl next door - in fact, I'm not sure but what I would prefer her to the little horror who inhabits (or should I say "infests") the neighbouring premises!
One wonders what Heidelbergensis really looked like?
© Kendall K. Down 2009
