Neanderthals declined rapidly and to extinction just a few thousand years after reaching their peak. Why? It's a mystery we're still piecing together. Now, an article recently published in Proceedings of the Natural Academy of Sciences provides yet more evidence that climate change is (at least partly) to blame.
"The Neanderthals were the human species closest to ours and lived in Eurasia for some 350,000 years," co-author Vasile Ersek, a senior lecturer in physical geography in Northumbria University's Department of Geography and Environmental Sciences, explained in a statement.
"However, around 40,000 years ago – during the last Ice Age and shortly after the arrival of anatomically modern humans in Europe – they became extinct... Our study suggests that climate change may have had an important role in the Neanderthal extinction."
A team of international researchers reached this conclusion after examining stalagmites, a type of rock formation found in caves. They grow extraordinarily slowly – roughly equivalent to a width of paper every year – trapping within their many layers a scrupulous record of the changing climate over the millennia. This is because even a small drop (or rise) in temperature can change their chemical composition.
The study includes two stalagmite-containing caves in Romania, which offer the most extensive and detailed records of climate change in continental Europe.
Importantly, the composition of these stalagmites reveal a period of recurring spells of cold, dry weather between 44,000 and 40,000 years ago, ie exactly when the Neanderthal population plummeted (according to current archaeological evidence). During this time, weather would remain icy for centuries or millennia before rising rapidly.
While this is correlational rather than causal, it seems to suggest that changing temperatures could, at least in part, be responsible for the Neanderthal's grisly fate.
Then again, Neanderthals were a robust species. They had existed for more than 350,000 years and withstood previous ice ages. What made this particular weather pattern so different and how were our ancestors Homo sapiens, who had only very recently arrived on the scene, able to survive when the Neanderthals were not?