"Ancient giant animals that once roamed Australia were not wiped out by climate change as was previously assumed, a study has shown. Human communities that lived on the continent 50,000 years ago might instead have hunted the megafauna to extinction.
Around 45,000 years ago, many of the unique megafauna species that thrived in Australia disappeared. Among the casualties were huge 1,000-pound kangaroos, two-tonne wombats known as diprotodons, and 400-pound flightless birds. There were also 25-foot-long lizards that looked right out of a sci-fi movie, and marsupial lions and tortoises the size of a car were also decimated in just a few hundred years."