The story of the biodiversity crisis starts with a cold-case murder mystery that is tens of thousands of years old. When humans started spreading across the globe they discovered a world full of huge, mythical-sounding mammals called “megafauna”, but by the end of the Pleistocene, one by one, these large animals had disappeared. There is no smoking gun and evidence from ancient crime scenes is – unsurprisingly – patchy. But what investigators have learned suggests a prime suspect: humans.
Take the case of Genyornis, one of the world’s heaviest birds, which was more than 2 metres tall and weighed in excess of 200kg. It lived in Australia until, along with many other megafauna, it went extinct 50,000 years ago. In North America, giant beavers weighing the same as a fridge and an armadillo-like creature called a glyptodon, which was the size of a small car, existed until about 12,000 years ago, when they, too, went extinct. In all, more than 178 species of the world’s largest mammals are estimated to have been driven to extinction between 52,000 and 9,000BC.
