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DNA evidence proves climate change killed off prehistoric megafauna Chris Turney , UNSW Australia and Alan Cooper Imagine a world populated by woolly mammoths, giant sloths and car-sized armadillos – 50,000 years ago more than 150 types of these mysterious large-bodied mammals roamed our planet. But by 10,000 years ago, two-thirds of them had disappeared. Since the end of the 19th century, scientists have puzzled over where these “megafauna” went. In 1796, the famous French palaeontologist Georges Cuvier suggested a global catastrophe had wiped them out. Others were appalled. The great Thomas Jefferson was so against Cuvier’s idea he sent an expedition to try to find vast herds of these animals grazing contentedly in the American interior. The only thing anyone could say with certainty was there should be a lot more of them than we see today. Alfred Wallace, who wrote the first paper on evolution by natural selection with Charles Darwin, noted that “we live in a zoologically ...