Exactly why the Neanderthals were wiped out remains a mystery, but now a new study says that a volcanic eruption, one possible theory, is likely not to blame for the demise of these human ancestors.

Supposedly about 40,000 years ago, the Campanian Ignimbrite super-eruption, which occurred in present-day Italy, dramatically cooled the climate. But researchers from the University of California at Berkeley say that the lava and ash that blanketed this region wasn't enough to lower temperatures to be a significant contributor to the fall of Neanderthals.

"Neanderthal decline started well before the eruption, so if there were just a few scattered populations that were hanging on at the brink, it's hard to say what might have pushed them over the edge," study co-author Benjamin Black told Live Science.

Some experts believe that their inferior intelligence caused Neanderthals to die out when competing for resources with early humans. But new studies have shown that they were actually just as smart as modern humans.

Another theory was that they simply bred into the ancestral human population after hooking up some 50,000 years ago, to the point that they were no longer recognized as their own sub-species. This latest study explores the option that a volcanic eruption froze out the Neanderthals, a population that disappeared between 35,000 and 41,000 years ago.

So Black and his colleagues used existing data on rocks from the eruption and combined those with climate models. They determined that the climate would have cooled at most about nine to 18 degrees Fahrenheit (five to 10 degrees Celsius) due to the eruption. While this is indeed a sudden drop in temperature, Neanderthals were used to this kind of climate, and it likely would not have been enough to wipe them out, researchers say.

What's more, Neanderthals were already extinct in Italy at that time.

While the fate of the Neanderthals still remains a mystery, this study provides insight into their downfall and sheds some light on how our ancestors coped with climate changes.

The findings were presented Dec. 18 at the annual meeting of the American Geophysical Union in San Francisco.

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