Study Revealed Both Humans and Climate Change Killed Off Ice Age Giants, But How?

Patagonia in South America was once the home of Ice Age giants, like huge sloths, bears and saber-toothed cats. Suddenly, they all died at exactly the same time--around 12,300 years ago.

A new study published in the journal Science Advances revealed that the species were killed off as a result of human activities and rapid climate change.

Molecular biologist Alan Cooper of the University of Adelaide said his team discovered that human hunting drove a swift blow to the populations of these Ice Age giants. Thus, they were unable to cope with the rapid global warming and were eventually wiped out from the Earth.

The researchers studied ancient DNA from teeth and bones discovered in caves in Patagonia and Tierra del Fuego. The team included scientists from the University of New South Wales in Australia, University of Colorado-Boulder in the United States and University of Magallanes in Chile.

"Patagonia turns out to be the Rosetta Stone--it shows that human colonization didn't immediately result in extinctions, but only as long as it stayed cold," Cooper said, as per Economic Times.

Yet after a thousand years of humans roaming the icy Patagonia, the southernmost tip of South America, the Earth began to rapidly warm up. This resulted in the extinction of these megafauna within 100 years.

Chris Turney of the University of New South Wales said Americas are unique because humans moved through two continents--Alaska to Patagonia--experiencing different climates.

Interestingly, the only large species to survive the mass extinction are the ancestors of the modern alpaca and llama, the vicuna and guanaco.

How their ancestors lived through the mass extinction could be a source of knowledge about their strategy for survival.

Even more, this study reinforces what might happen to creatures that are affected by both humans and climate change.

The Bramble Cay melomys, a small rodent found only in Australia, recently went extinct, becoming the first recorded mammal to die off due to human-caused climate change. Its extinction may be the most alarming warning sign yet on how climate change can completely alter our planet, if we don't do something about it immediately.