I've noticed our puppy doing this occasionally, mainly outside but we don't have carpets. Reading this I'm wondering if we should give him some weetbix to increase the fibre in his diet (he is on Orijen puppy food). Not sure how keen he would be on it though, are bananas any good? He is always trying to steal them off DS!
I didn't think my pup would as he is a very picky eater to the point where I was practically wailing and nashing teeth when we first got him as I didn't know how I would every feed him enough to make him grow!
But he goes crazy for it. The sight of the box has him spinning and it is the only thing he has ever done that for. Mixing it in his food is the only time I am ever sure of of an empty bowl so I wouldn't dismiss without trying first.