Probably booms and busts all the time in places with no people around to catch it and get it reported. At Shiprock I tried to avoid packrat middens by sleeping out on more exposed places but it didn't work. There was a rat under the one boulder near my sleeping spot on the Climbers ledge. He kept visiting my camera pack all night after the ziplock of trailmix. There have to be plenty in the cave, (one night there), where there is food, cover and water. On my last night on a big exposed boulder on the South talus slope I had one who came and climbed around on my sleeping bag. I could hardly shake him off.
Plus the dang kissing bug.