The extinction of Neandertals is a huge challenge for paleoanthropologists. Neandertals and modern humans are believed to have evolved from a common ancestor about 500,000 years ago. Some researchers usually thought of Homo heidelbergensis as this common ancestor, but other hypothesis suggests that Homo heidelbergensis existed as an species only in an European niche, whilst there is a new parent species yet to be found. In any case, the ancestor evolved into Neandertals in Europe and Homo sapiens in Africa. Neandertals lived in Eurasia 200,000 years before Homo sapiens arrived from Africa. About 60,000 years ago, succesful migrations of African modern humans came into Eurasia and then also quickly to Western Europe. It is not known when they first met Neandertals, but genetic evidence shows interbreeding between both species in different periods.
A study by Tom Higham et al set the extinction of the last Neandertals around 40,000 years ago. It is based on radiocarbon dating from 40 sites across Europe. Assuming that Homo sapiens first reached Europe about 45,000 years ago, this implies a period of Neandertals & sapiens coexistence of between 5,000 and 10,0000 years.
However, the study does not include remains from Gorham’s Cave in Gibraltar, where Neandertals apparently survived until c. 30,000 years ago.
We can clearly say that Homo neanderthalensis was a successful species. It existed on the planet likely for at least 300,000 years, depending on the limit we set between the Neandertal origins and the so called pre-Neandertal populations. They survived massive climatic changes, with subsequent local extinctions, expansions and adaptations… What could happen with them?
The answer maybe: nothing in particular made them disappear, but a combination of factors impacting the Neandertal populations for thousands of years. The time scale is long enough to consider a slow, steady reduction in their number. Paola Villa and Wil Roebroeks discuss some hypotheses for the demise of Neandertals as a result of the theoretically superiority of Homo sapiens in a wide range of domains:
- Inventiveness and capacity for innovation
- Complex symbolic and linguistic abilities
- More efficient hunting strategies
- Exploitation of a broader range of resources including plants and aquatic ones
- Projectile technology
- Heat treatment of lithic raw materials
- Hafting technology
- Planning capacities including larger scale social networks as shown by large transport distances of raw materials
- Environmental flexibility
- Memory capacity
- Larger population sizes
We now know from genetics that there was interbreeding between Homo sapiens and Homo neanderthalensis. Part of the Neandertal DNA is in almost every human population outside Africa (+info). Some fossils in the Levant area may even show some physical evidences. Researchers as Villa, Roebroeks and Zilhão suggest that Neandertals never became extinct but a biological part of our species. In other words, the old denomination of ‘Homo sapiens neanderthalensis’ (widely discarded in the last decades) could make sense… However, this actually sounds too challenging: the morphological differences are relevant enough to consider two separate species. And the presence of Neandertal DNA in modern humans is actually very limited.
Some scientists focus on the lack of adaptability of Neandertals to extreme cold weather, in comparison to modern humans using superior technology… Here are some discussions around this:
- Some Homo sapiens populations migrated for the first time to the Middle East around 100,000 years ago, but they ‘lost’ against the Neandertals population who were existing there before. Did Neandertals have superior technology by then?
- After 30,000-40,000 years then Homo sapiens went back to Middle East and they could extent throughout Europe because they had more technology, for example they had needles to make clothes, tents and boots; they had oil lamps… Both Neandertals and H. sapiens suffered the same cold weather, both survived, but maybe not in the same extent.
- We cannot say in general that the ability of Neandertals with technology was inferior. They successfully expanded to Western Europe as well as far East in Asia as Uzbekistan, Siberia, Mongolia…
- However we think they did not reached Africa. They did not develop sailing craft (at least not extensively) to cross Gibraltar. At the time they coexisted with sapiens populations, some of these were capable to cross the ocean to Australia.
Three researchers from Stanford University and Meiji University have created a model showing a correlation between the Neandertal extinction and the cultural superiority of modern humans. Moreover, such cultural advantages could have led to a feedback loop (more advanced culture -> more dominant -> increasing gap in the cultural advantage).
Another study proposes that their cannibalistic behaviour played a major role in their extinction. If their cannibalism strategy was focused merely on nutrition and not ritual purposes, and they had to compete with modern humans, cannibalism actually had a negative impact pushing the neandertals extinction. Again, this may not be the main cause, but another negative factor combined with the rest as described above.
We will read more and more studies around Neandertals. Fortunately, the number of Neandertal fossils and sites to study are becoming quite significant (never enough, though). Paradoxically, Neandertals were probably always a small population (maybe one tenth of the total ancient African population or less), but they are really important for us: we can better understand our origins by understanding our past interactions with Neandertals in several locations. We already found some of those locations, but for sure many others are yet to be found, given their wide presence.