When I slept outside in central Europe, I often recognized extremely loud snoring noises. It's not really rattling but more like rhythmical breathing. I heard it as a kid for the first time and I remember that it scared the hell out of me :)
What animal can cause such noises?
Worth to mention: a mate once told me that hedgehogs can sleep very loudly. However, as I've researched a little bit, it doesn't seem to be true (but can't really figure out a definite answer).