I think the tail wagging is sooo cute. My guys do when playing in the clear tubes also. They will face each other in the middle and wag like crazy. I just figured it is because they are playing. As for clumping litter my experience with it has not been good. I usually use newspaper pellets but while I was moving about a month ago I ran out of litter that day and my boyfriend went to the store to pick up the litter for me. He brought back clumping. It was too late to get to petsmart so I ended up using the clumping for a little under a week. I noticed one of my guys not really eating or playing as much so I gave hairball stuff to him and in his pooh was a bunch of the clay colored clumping litter along with the greasy hairball stuff. Sorry to be so descriptive but it was definitely the litter-I could tell by the color(I know from the list that I'm not the only one that checks out my ferrets pooh :-). After he got that out of his system he was back to normal. Now I vow never to use the stuff again. I try to keep the paper pellets stocked up but if I ever run out again I'll settle for newspaper or now the supermarkets near me also sell paper pellet dog litter. Michelle and the four fuzzbutts [Posted in FML issue 3106]