There's a theory that snoring at night in sleep is a subconscious defence reflex-a warning sound that frightened potential predators away from the mouth of the cave when our lower-paleolithic ancestors huddled in vulnerable sleep. That group of nomads, cameleers, sheep and goat herders, farmers, and guerilla fighters lent credibility to the idea, for they snored so thunderously and with such persistent ferocity through the long, cold night that they would've frightened a pride of ravenous lions into scattering like startled mice.