In this near-desert, mule deer, coyotes, quail, and humans survive only by possessing special skills and abilities; without them, they cross the threshold from survival to extinction. The same was true in the past. About 30 million years ago, major shifts in temperature and humidity here brought great changes in plant life. The animals that survived that transition were those that evolved new behaviors, different bodies, and new abilities to survive, though long-term survival was still not assured. Fossils from the John Day country portray a healthy forest ecosystem long gone and suggest reasons for its disappearance, offering information that may help predict the future of modern species.