I bought Rowdy at a shelter that took in dogs that the Humane Society wouldn't take.  I think the reason the Humane Society wouldn't take him was because his previous owner had written down that he was destructive.  (She felt crating was mean and wouldn't do it when he was left alone for long hours.  Not a wonder he destroyed her stuff!)  I crate him sometimes when I go to work.  The rest of the time he is loose in the house or outside with our German Shephard mix and they entertain each other.  Anyway, that's entirely off the point....

The only "problem" I have with Rowdy is that he is mouthy when he gets excited.  He will "mouth" your arm or hands.  Not like a bite, but just take them into his mouth.  (He also does it to the Shephard, Schatzi, but it doesn't bother her...)  Is this common for ratties, and have you successfully broken the habit?  Rowdy's the first rattie I've bought- we usually get big dogs- and while I love his crazy, exciteable mannerisms, the mouthing gets a little sloppy.