Fate of Neanderthals

The Fate of the Neanderthals

The Neanderthals (or Neandertals) can be accurately described as our closest evolutionary kin, the closest relative to modern humans.  Evolutionary science being somewhat inexact, these creatures have been classified as a species distinct from Homo sapiens – Homo neanderthalensis – and as an extinct variant or subspecies of the same – Homo sapiens neanderthalensis – which some scientists believe is more accurate.

Regardless, they suffered a rather abrupt and mysterious extinction about thirty to thirty-five thousand years ago and were replaced by another form, Cro-Magnon man, which flourished and survived until as recently as 8,000 B.C.E.  Cro-Magnon was undoubtedly more advanced and more similar to modern humans as we exist today, and are considered to be the first form of modern man by those paleoanthropologists who insist neanderthalensis was a separate species.

Though the disappearance of an older, less advanced form and the emergence of a newer, more advanced one is the normal process of evolution, the disappearance of the Neanderthals (named for the Neander Valley in Germany where the first recognized fossil find was made) remains a puzzle for several reasons.  The Neanderthals were quite well adapted to their environment and survived for tens of thousands of years.  They had definitely appeared on the evolutionary scene by 150,000 years ago (some say 200,000 years ago), and lasted at least until 35,000 years ago, perhaps in refugia (isolated relic populations) until as recently as only 24,000 years ago.

They sheltered themselves in much the same fashion as Cro-Magnons, using cave fronts and rock overhangs as naturally occurring shelters.  Both types occasionally made open encampments and used tent-like structures made of animal skins.  There is also evidence that both were capable of building huts that included stone paving.  In shelter arrangements, the Neanderthals were essentially identical to Cro-Magnons.

Both types were hunter-gatherers, hunting large mammals and snaring smaller ones for meat, while gathering fruits, nuts, berries, and other vegetation to complement and supplement their diets.  Some have asserted that Neanderthals were strictly carnivores because little or no preservations of plant foods have been found at Neanderthal sites, but stone implements appropriate for cracking or grinding seeds, etc. have been found among Mousterian artifacts.  (“Mousterian” refers to a particular type of stone implements associated exclusively with Neanderthals and similar fossils.)

In addition to having shelters and a diet generally similar to Cro-Magnons, Neanderthals shared another practice with them: intentional burial of their dead.  One reason we have good fossil evidence of both types is that ritual burial became a practice among at least some groups of both.  Cro-Magnon sites have included cave art, something yet to be associated with a Neanderthal find, but the intentional arrangement of cave bear bones in a certain order by Neanderthals seems to indicate some sort of reverence for the animal or perhaps even religion.

Cro-Magnons did have more advanced implements and innovations.  Fish hooks and nets, shoes, headgear or hats, sewn clothing, and needle-and-thread are among the Cro-Magnon implements that Neanderthals lacked.  While Neanderthals undoubtedly ate fish and even (rarely) invertebrates such as clams, Cro-Magnons seem to have engaged in organized fishing (indicating they thought ahead to such events as annual salmon runs).  They also developed long range trade, which Neanderthal finds show no evidence of at all.

So how did the more recent group so completely and suddenly (in evolutionary terms) supplant the other?  Some have suggested that the Neanderthals were absorbed into the Cro-Magnon populations.  It has never been definitively proven that interbreeding between the two was possible, but it could have been.  The strongest proponent of the interbreeding hypothesis is Erik Trinkaus of Washington University who has made fossil finds that he claims are hybrids.

Some caves were definitely inhabited by both types, but essentially all such finds show a sterile period of stratification between the last Neanderthal fossil deposits and the first Cro-Magnon ones.  Some inter-stratification of the two has been suggested, but is disputed.  Furthermore, mitochondrial DNA analysis has discovered an indicator of Cro-Magnon maternal DNA in modern populations in Europe, the Middle East, North Africa, and Central Asia.  No such evidence of a maternal line originating with Neanderthals has been found in any modern populations.

Undoubtedly, Cro-Magnons and Neanderthals at least co-existed for anywhere from eight to fifteen thousand years.  It should be borne in mind that co-existence in time doesn’t necessarily translate to intermingling.  At least one Neanderthal culture (there were numerous different ones) shows clear indications of Cro-Magnon influence, to the point of suggesting some cultural exchange.  Without a doubt, the two did have experience of each other in some locales, but how widespread and extensive has thus far not been proven.

Due to the indubitable intermingling, the – I think doubtful – hypothesis of interbreeding has been asserted.  Another more disturbing but definitely possible hypothesis is intentional genocide, combined with greater susceptibility of Neanderthals to Cro-Magnon pathogens.  We have unfortunate but powerful examples of these phenomena in the colonizing (and eventual takeover) of the New World by Old World European cultures.  While there was some friendly interaction between the European settlers and Native American cultures, the more “advanced” culture more widely sought the eradication of the native one, and European pathogens – most notably smallpox – wreaked havoc on the native populations.

Jared Diamond, a professor at UCLA and writer of popular science books and articles, has been perhaps the most vocal proponent of the genocide/pathogen hypothesis.  Short of a plethora of fossil finds showing Aurignacian (Cro-Magnon) flint implements buried in Neanderthal skulls, this one will be  hard to prove.  It will, however, be just as hard to disprove.  It is possible that Cro-Magnons did engage in systematic warfare on Neanderthals, but it is difficult to believe that such warfare alone accounted for their disappearance.  There are after all still remnants of Native American cultures in North, Central, and South America.

It seems much more likely that the more advanced, more sophisticated Cro-Magnons simply outcompeted their more primitive, less sophisticated brethren, as is the usual process of natural selection.  Early readers of Darwin misinterpreted his “struggle for survival” to mean bloody pitched battles, “red in fang and claw,” when it usually meant nothing more than a more efficient way of gathering food, surviving, and getting one’s genes into future generations.  It is always juicier and more fun to picture the grotesque than the mundane.

But merely saying “outcompeted” doesn’t provide a complete explanation: outcompeted how?  Steven L. Kuhn and Mary C. Stiner (University of Arizona) have put forth the theory that Neanderthals had no gender-specific division of labor and Cro-Magnons did.  In other words, Cro-Magnon men mainly stuck to hunting big game; the women stuck to snaring or hunting smaller animals and gathering vegetation (less dangerous activities).  Thus the child carriers survived in greater numbers and replenishing the population was more effective.

Furthermore, a full-time force of gatherers insured a steady supply of food when the hunting was poor.  (Ask any modern day hunter, it’s a hit or miss proposition; even with a rifle instead of a spear, if you don’t see a deer you can’t kill one.)  This is unfortunately probably unverifiable, as prehistoric people left no records of their exact habits.  But it is certainly logical and could account for a gradual total ascendance of the Cro-Magnons.

Another “out-competition” theory hinges on anatomy.  Neanderthals were more acclimated to the colder temperatures of the last ice age.  They were stockier and shorter, traits which preserve body heat better.  Cro-Magnons were taller, with longer and leaner limbs and could probably run faster, and their leaner build would dispel body heat better over long distance runs.  The comparative anatomy of their pelvises alone shows Cro-Magnons would have been better, faster runners than Neanderthals.  They would have been better at chasing down animals and running away from danger, using less energy to do it.

In the final analysis, it seems that Cro-Magnons were simply better adapted to the conditions under which they survived and Neanderthals disappeared.  A period of 10,000 to 20,000 years would have been enough time for their superior adaptations to push Neanderthal Man out of the picture.  That span of time qualifies as “sudden” in evolutionary terms.  Certainly, other factors may have contributed to Neanderthal’s demise, but it seems clear that Cro-Magnon’s superior adaptability alone would have been enough.