The Science Behind the Story

The Science Behind the Story
Neil’s Notes from the Underground

High Five
Handprints in the Cueva de las Manos, Argentina, are up to 13,000 years old. Similar handprints from Indonesia date to 40,000 years. Intriguingly, most are left-hand prints and those of women (in women, the ring and index fingers are about the same length; in men, the index finger is shorter).

Our forefathers, Early Modern Humans (EMHs), probably reached southeastern Europe less than 45,000 years ago. It’s likely that we overlapped with Neanderthals for just a few thousand years before they went extinct.

The rapid demise of the Neanderthals has been attributed to many possible factors, including genocide by EMHs, infection from EMH-carried disease, competition for food and resources, and climate change (although Neanderthals made it through numerous periods of substantial climate change over the previous 250,000 years). The fossil record indicates that Neanderthals disappeared only after EMHs moved into their territory. Analysis of a deep scratch on a rib of Shanidar 3, an adult male Neanderthal, who lived in present-day Iraq more than 50,000 years ago, suggests he was hit by a spear thrown by an EMH according to Duke investigators.

Rhinoceros Front Horn
Rhinoceros on a wall of Chauvet Cave in France from 20,000 to 30,000 years ago. Note the two-meter (6.5’) front horn.

Based on the brief overlap in time of EMHs and Neanderthals in Europe, the fossil evidence, and the xenophobic nature of early (and many would say current) man, it’s a good bet that genocide played a key role.  However, EMH-carried disease is also a likely cause that’s consistent with the data.  In the early 1500s, Cortés unintentionally brought smallpox to the Aztecs and saw a die-off of between 60-90%. Similarly, in the 1600’s, Native Americans were nearly eradicated in New England by diseases brought by European settlers.

A great deal of research has substantiated that EMHs and Neanderthals inter-bred, and the average non-African person of today owes 1-5% of their genetics to Neanderthals.  Neanderthal genetics have given us some good things like an increased ability to fight viruses, but they also brought along some real negatives, including predispositions for type 2 diabetes, lupus, biliary cirrhosis, depression, actinic keratosis, and Crohn’s disease.

Approximately 40,000 year-old jewelry, flint tools and bone needles from the Grotte du Renne in France (Caron et al. 2011- PLOS ONE)

Was There Peace?
Scientists have found layers of “mixed” technologies that suggest that Neanderthals
may have learned some of our innovations, and we learned some of theirs. This mixed layer is known as the Châtelperronian industry and occurs at about the same time as our story.

Many researchers have concluded that something happened around 45,000 years ago that dramatically and beneficially impacted EMH development and their resultant diaspora out of Africa. Humans successfully made it north into Europe and they were off to the races, overwhelming the Neanderthals and other hominids and spreading to all parts of the globe. Certainly population blossomed, and in what Jared Diamond has popularized as the Great Leap Forward, technology, culture, art, and music expanded more in the short period thereafter than it had in the past million years. Even if some of these technological and cultural breakthroughs had happened earlier, the intensification of them is undeniable.

Meet Venus of Brassempoy!
She is one of the earliest known realistic representations of a human face, carved in ivory, about 25,000 years ago from SW France. This and other evidence suggest that Homo sapiens had wavy hair and may have braided it.
(Photo by Jean-Gilles Berizzi)

What caused this explosion of creativity and success? Various researchers have proposed genetic changes, for example to the FOXP2 gene, which allowed for better language skills (note: genetics within the Basque population suggest that this oldest of Western European languages is probably the most similar to what Moctu and his brethren spoke, so a number of Basque words show up in the book).  Others have called on our interactions with the Neanderthals for better (e.g. technology transfer and modest beneficial gene flow), or for worse (Neanderthal predation that forced us to become the shrewd, and at times, bloodthirsty race we are).

We’ll probably never know for certain the cause, or causes, of the transformation, but that hasn’t stopped us from speculating.

A single breakthrough, such as mastery of fire starting, or the atlatl (spear thrower, which allowed for greater range and safety during hunting) could have played a major role. Studies show that a small but consistent advantage can make all the difference — just a one percent difference in mortality could have led to the extinction of Neanderthals and the supremacy of EMHs in 30 generations or about 1,000 years.

Neil Bockoven with Fossil