As annoying as it may be for their owners, some cats simply enjoy digging and playing in their litter boxes.
But when scratching in the litter box becomes excessive, more likely, the cat is trying to fulfill her instinctual urge to cover up waste. Something isn't signaling the job is done, so she just keeps scratching and digging. The prompt to "stop now" is probably a combination of both visual and
scent cues. As long as she sees something there, she keeps on digging.
Covering up the deposit also reduces the odor, so the cat keeps shoveling litter until the smell level falls to what she wants. Correcting the problem depends on its cause.
First, if the box is so small that she's unable to maneuver for adequate cover-up, the behavior may become prolonged. In fact,
some cats finish eliminating inside the box, then step out and try to cover by scratching the sides of the box or floor! The deposit remains visible,
so the cat keeps scratching. In these cases, often a large box helps fix the problem.
Second, a wide range of cat litters are available today, and cats react differently to different products. So try another type of litter and see how the behavior is impacted.
