Every morning at around 4.30 - 5am. He's lovely, and I will get up and take him downstairs to open the door and let him out, but then more often than not I can't get back to sleep. I'm knackered. But the main point is, is the biting just his way of communicating that he wants to go out? I find it all very interesting how they tell you stuff, as a fairly new cat owner.