Do cats have an instinct to use a litter box?
Cats do have an instinct to tend to their elimination needs by digging and covering. Most adapt very readily to being presented with a tray of sand or gravel and take it from there. That being said, cats have definite litter box preferences, and more often than not, when a cat avoids the litter box, generally the fault lies more with the person and less with the feline.
Cats have highly sensitive noses and will not use filthy litter pans. Imagine your own aversion to a poorly kept public toilet and you have some idea of your cat’s reaction. It’s always best to have one more litter box than the total number of cats in the house. Even when that “rule” is enforced, however, boxes should be scooped daily.
One mistake pet owners make is failing to realize that the plastic from which most litter pans are made will, over time, absorb urine smells. No amount of scrubbing will make these scents go away. Try to replace the litter box with an entirely new unit at least twice a year.
Also be aware of your cat’s own preferences. Some do not like to be observed while doing their “business” and will want their box in a private area or will prefer a covered pan. Others will refuse to enter a covered litter box at all. These are also instinctual imperatives, since taking care of their needs puts the cat in a temporarily vulnerable position.