It's not as quiet as you think. First time you hear a mountain lion scream in the woods, sleep is pretty much over for the night. (Think something that sounds like a woman trapped in a coffee can screaming in pain). Foxes can sound like something that murders people for fun, too. There's also plenty of night birds. One sits in the tree outside my bedroom window and yells "Whip-poor-will!" every ten seconds from about 11pm to 7am. Last year it was an owl that yelled "saaaawww -wheet!" every thirty seconds or so in the middle of the night.