The Antropocene is usually said to have begun with the industrial revolution, or perhaps even later, with the explosive growth in population that followed World War II. By this account, it's with the introduction of modern technologies—turbines, railroads, chainsaws—that humans became a world-altering force. But the megafauna extinction suggests otherwise. Though it might be nice to imagine there once was a time when man lived in harmony with nature, it's not clear that he ever did.