If you spend enough time in the mountains of Appalachia, you start to learn the unwritten rules of the woods. At night you should hear the sounds of life—crickets chirping, frogs croaking, insects buzzing in the dark. Those sounds mean everything around you is normal. But when the woods suddenly go silent, when the crickets stop and the frogs disappear, old timers say that’s your warning that something isn’t right in the forest. Predators, unseen dangers, and things we don’t fully understand can