While I understand cats and their desire to bury their waste when they are finished, my cat often sits in the litter box and digs against the plastic side of the litter box, not actually in the litter itself, so much so that he is actually wearing down the sides in places.
Why is he doing this? Is it a problem (other than the destruction of the litter box)?
It is most likely a combination of marking his territory (aka the litter box), and also possibly cleaning off his paws from the litter that gets in-between the pads. It's not really a problem, because trying to stop it could give the cat an aversion to the litter box, which results in the cat using anything else as a litter box.
It could also be that the cat is entertaining himself by digging in the litter.
