\" \" Spiders are creepy and crawling, but their choice of residence isn't necessarily your mouth -- especially while you're sleeping. Holger Wulschlaeger/ThinkstockHumans swallow an average of eight spiders each year while sleeping! In fact, it's extremely unlikely a spider would even approach a sleeping human, much less crawl into their open mouth and wait to die. A sleeping human is nothing but noise and vibration, from your breath and heartbeat, to tossing and turning, to snores, snorts and other sounds. Finally, you'd have to actually swallow while sleeping, which is not automatically going to happen without a little effort on your part [source: Soniak].