Mountain lions were eliminated from the eastern United States in large part because of our fear of them. And as they make a comeback in the west, mountain lions, or “pumas” (Puma concolor), are certainly coming into conflict with humans. That said, there’s evidence that mountain lions will predictably avoid places with lots of people. In fact, a new study published today in Current Biology shows that having them around actually makes us safer. The deer, though, have apparently gotten wise to them, and as such, puma presence appears to repel deer from landscapes that are more fragmented by roads.