Humans, Not Climate, to Blame for Mass Extinction of Ancient Species

A new study unequivocally blames humans, and not the climate, for the worldwide mass extinction of large ancient species dating back to 100,000 years ago.

"Our results strongly underline the fact that human expansion throughout the world has meant an enormous loss of large animals," postdoctoral fellow Søren Faurby of Aarhus University said in a statement.

Scientists have struggled to figure out what led to this mass extinction of the world's large mammals (also known as megafauna) during and immediately after the last Ice Age.

Climate change was one theory, especially since the climate significantly changed during that time - as it had during previous Ice Ages. It's possible these larges species could not adapt or find alternative shelter, and died off. But, the hole in this theory is the question of why was there a mass extinction during this Ice Age, and not during all the prior ones?

So, scientists turned to man, whose "overkill" exterminated many of the large animals as they explored various countries. This is either because species could not withstand human hunting, or man was wiping out the prey they depended on for survival.

To get to the bottom of this, researchers conducted the first global analysis and relatively fine-grained mapping of all the large mammals (weighing at least 10 kg) that existed 132,000-1,000 years ago when such species were wiped out.

A total of 177 large species disappeared during such time, taking place in virtually all climate zones and almost every continent. Extinct species included woolly mammoths, forest elephants, sabre-toothed cats, giant armadillos and mastodons.

Based on these findings, climate change may have had a hand in the mass extinction, but bears little weight as the root cause.

Researchers therefore are confident in pointing the finger at humans.

"We consistently find very large rates of extinction in areas where there had been no contact between wildlife and primitive human races, and which were suddenly confronted by fully developed modern humans (Homo sapiens). In general, at least 30 percent of the large species of animals disappeared from all such areas," Professor Jens-Christian Svenning concluded.