From ScienceDaily:
A team of researchers from a number of European and American research institutions, including Northumbria University, Newcastle, have produced detailed new natural records from stalagmites that highlight changes in the European climate more than 40,000 years ago.
They found several cold periods that coincide with the timings of a near complete absence of archaeological artefacts from the Neanderthals, suggesting the impact that changes in climate had on the long-term survival of Neanderthal man.
…
“For many years we have wondered what could have caused their demise. Were they pushed ‘over the edge’ by the arrival of modern humans, or were other factors involved? Our study suggests that climate change may have had an important role in the Neanderthal extinction.”
The researchers believe that modern humans survived these cold stadial periods because they were better adapted to their environment than the Neanderthals.
Neanderthals were skilled hunters and had learned how to control fire, but they had a less diverse diet than modern humans, living largely on meat from the animals they had successfully pursued. These food sources would naturally become scarce during colder periods, making the Neanderthals more vulnerable to rapid environmental change.
In comparison, modern humans had incorporated fish and plants into their diet alongside meat, which supplemented their food intake and potentially enabled their survival. Paper. (open access) – Michael Staubwasser, Virgil Drăgu in, Bogdan P. Onac, Sergey Assonov, Vasile Ersek, Dirk L. Hoffmann, Daniel Veres. Impact of climate change on the transition of Neanderthals to modern humans in Europe. Proceedings of the National Academy of Sciences, 2018; 201808647 DOI: 10.1073/pnas.1808647115 More.
This thesis is, of course, vulnerable to the potential discovery of fish bones and plant offal in the remains of Neanderthal settlements.
There are many other theses on offer. From a collection made in 2014:
All we really know for sure is that, as a distinct human type, Neanderthals died out. There is a bonanza of speculation as to why that happened. Some say current humans crowded them out. Others say it was due to interbreeding with current humans (of course, for a minority group, that is a form of crowding out, just not necessarily a violent one). Alternatively, they died before we even got there. Or succumbed to an early industrial revolution. But according to one account, Neanderthals kept us alive precisely because we inherited some of their genes, not that it did them much good.
Some researchers look for physiological clues. Neanderthals tended to have shorter lower legs than modern humans, which helped them move more efficiently in the hills.” But, others point out, they had weaker Achilles tendons, and therefore inferior running ability, which “hits at the crux of why Neanderthals went extinct.” According to some, their large eyes caused their demise (because “more of their brains were devoted to seeing in the long, dark nights in Europe, at the expense of high-level processing”). Apparently, they hung on a while in the Polar Urals in northern Russia. But we really don’t know for sure what happened to them.
More recently: Human evolution: Did large brains cause Neanderthals to go extinct?
Did Neanderthals’ faces help them cope with the Ice Age?
In this week’s episode, slow immigration doomed the Neanderthals
and so forth.
See also: But are human groups “extinct” if their genes live on in us?