Chicago Tribune: It seems to be a law of nature that when people come, animals go. It happened in the past, and it’s happening again now. About 11,000 years ago, more than 130 species, including most large mammals such as the woolly mammoth, saber-tooth cat and a 5-ton ground sloth, vanished from North America. Scientists are still debating the reasons, but two leading suspects are excessive hunting by humans who had newly arrived from the Old World and devastating human-borne …