11.   As any responsible cat owner knows, eternal vigilance is the price of a pristine litter box.

12.   As her immune system fought the infection, the pain eased somewhat so she knew the litter box had been the cause.

13.   A true cat prefers your flower bed to her litter box.

14.   But now he does it begrudgingly, tiptoeing by the litter box with one hand pinching his nose closed.

15.   Cats use litter boxes.

16.   Dog litter boxes are just another, more convenient extension of that.

17.   Every cat owner knows that these pets cannot be herded, will not come when called and cannot be trained for anything but a litter box.

18.   Farmer, a flight attendant, decided to potty train Samson and Gigi because she was sick of the litter box, she says.

19.   For some people, a litter box may be the only way they can have a dog.

20.   He also uses their litter box and eats their food.