Mine pee in there mostly (and on their hammocks, ew), but they always wander out of the litterbox carrying some of the Yesterday's News. I keep finding little hoards of it in things for no apparent reason.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry