Bathtub vs. poopbox
Our cat has eliminated in the bathtub two times in the last week. She has never done this. She has always used the cat box. Does anyone know why?
Often, there's either something wrong with the box (not clean enough for your cat, not available, wrong location, etc.), or some stress (physical or emotional) is at work.
Some cats suffer from arthritis and this can make it difficult to get into the box. A tub isn't usually as easy to get into and out of as a litter box, though, so I'd not guess pain or discomfort due to arthritis as a cause in this case.
Is she acting different in any other way (could be a sign of a physical problem)?
Has anything changed in the house recently? Any added stress factors?
Has the litter box been moved or the litter brand/type changed?
Is she at odds with any other animals in the house?
Any disruption of her routine?
Addition or removal of a family member (pet or human)?
Any guests staying over?
The above are some of the reasons I've heard for cats to use a location other than the litter box. If it persists, I'd take note of the time and conditions, and see if I could find a pattern to it.
Please let us know what you find out. If anyone else has any input, please leave a comment.