Jan 25 2019

Rethinking Neanderthals

Published by under Evolution
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Old ideas die hard. The first extinct hominids found were Neanderthals, and our cultural conception of them was formed in the 19th century, a time rife with parochial attitudes toward “primitive” peoples. The first Neanderthal skeleton also happened to suffer from crippling arthritis, giving it a hunched over posture.

The cultural notion that our closest relatives were brutish and primitive became deeply embedded. Certainly, this idea has been moderated significantly in the last century, but not completely expunged. Meanwhile, paleontologists have discovered more and more evidence that Neanderthals were just a different breed of human. They were fully bipedal, so their gait was modern. They were more robust than Homo sapiens, because they were adapted to Europe’s Ice Age. But robustness should not be confused with brutishness.

Prof Clive Finlayson, director of the Gibraltar Museum, has a recent commentary on BBC’s website in which he punctures this outdated view of our closest cousins. He points out that this biased view of Neanderthals affects not just public perception, but scientific thinking. There have been many assumptions of Homo sapiens superiority, and that Neanderthals were essentially replaced by us through direct competition.

So this also reflects a common misconception about evolution itself, that “survival of the fittest” is always what determines which species endure, and is all about being more advanced and superior. Finlayson points out that we cannot neglect the factor of luck, which may, in fact, often be dominant. Homo sapiens may not have been objectively superior to Neanderthals in any specific way, but were simply better adapted to a changing environment. Neanderthal robustness, an advantage during glacial periods, may have been a hindrance during a warming climate. Sapiens may simply have inherited a better trade-off of features for that period in time.

Modern humans may also have had some objective advantages, but that should not be our base assumption simply because we survived. We also have to consider that modern Europeans have about 2% Neanderthal DNA. This means there was significant interbreeding between humans and Neanderthals. In fact, some scientists still contend we were the same species.

Further still, we have to realize that humans vs Neanderthals is a false dichotomy. There were likely many subspecies in Europe and Asia for the last 100 millennia.  The Denisovans, for example, are know from limited samples from which we were able to obtain DNA. In fact, we now have essentially three types of evidence to indicate the presence of hominid species during this time – tools, bones, and DNA. Finlayson points out that too often we assume that a certain tool set was used by a specific species, but those assumptions are not well evidenced.

It’s possible there was a continuum of subpopulations and culture intermixing across Europe and Asia. No simple story, such as modern human superiority and wholesale dominance, is likely to be true. As we find more pieces to this puzzle, the only thing we can be really sure of is that we have very few pieces to the overall puzzle. As more of the picture emerges, it is likely to get much more complex.

Perhaps by coincidence, the BBC also has a separate article once again attributing greater ability to Neanderthals than previously thought. Researchers looked at 300,000 year old preserved wooden spears associated with Neanderthals. It was assumed that Neanderthal spears were only good for stabbing, not throwing. However, the researchers studied replicas with skilled javelin throwers, and found that they could hit a target with sufficient force and accuracy to kill a large animal at 20 meters. That would make Neanderthals more versatile and dangerous hunters than previously thought.

Previous studies only looked at unskilled throwers. It is possible that modern human javelin throwers are not a perfect analogy to Neanderthal hunters, but then again unskilled throwers are probably an even worse analogy. The Neanderthal bulk may have made them less agile, but they were strong. It is probably safe to assume that a hunter was highly practiced, and so probably closer to a skilled thrower than and unskilled one. At the very least the current study shows the upper limit of potential for the weapons themselves. Even if they were deadly at 10 meters, that’s enough for a stealthy hunter to get a kill.

I love it when evidence forces us to change our preconceptions, and this is definitely one dramatic case of this. Understanding evolution means having a more nuanced and complex view than simple “survival of the fittest.” We also need to be skeptical of simplistic notions of “modern” and “primitive.” Finally, the mere fact of extinction does not imply inferiority or weakness. So far, all species eventually go extinct. It is largely a matter of time and luck. This is because much of adaptation is not objectively better, but simply suited to the local niche, including all sorts of trade-offs. Evolution cannot see the future, and so it is common for adaptation to make trade-offs that eventually lead to extinction.

The dodos, for example, lost the ability to fly because they simply did not need to. Flying is extremely costly, and it makes perfect evolutionary sense to ditch it unless it provides a significant survival advantage that is worth the huge investment in calories. But these evolutionary pressures could not foresee the arrival of humans, and their ubiquitous companions, rats. The poor dodos, laying their eggs on the ground, were highly vulnerable to these new predators. This does not make them inferior or primitive, just unlucky.

Neanderthals too may have simply been unlucky. Selective pressures adapted them to one climate, and then came another climate with a species trying to fill the same niche with a more fortuitous set of trade-off for the new climate. Even then, they interbred and split off numerous sub-species. They may have also shared culture, and therefore tools. We don’t know exactly what happened, but we know enough now to get rid of any assumptions, step back, and gather more evidence.

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