I have three cats. Two of them are sisters, who have been with me since they were born 24 years ago. One of them tends to get sick, and vomits sometimes. Another, and I haven't figured out which yet, sometimes pees on a rug outside of my office door. Neither of them have made a habit of doing this so I attribute it to some malady of old age. Ella, my third cat, is just over a year old, and she makes it her business to tell on the others, by making exaggerated digging motions in the area of where one of them has either peed or vomited. She uses that same gesture to let me know when she doesn't like whatever food I have given her, scratching alongside the bowl as if to cover it up. I have four litter boxes, which I clean every morning. While I am cleaning the first one, Ella will dig along side the next one, as if I needed her to tell me that that one needs to be emptied too, then she'll move on to the third, and if she doesn't think I've done a good enough of a job on any of them, she'll let me know about that as well. This morning, she was making digging motions alongside the rug outside my door, so I thought that one of them must have soiled it during the night. I couldn't smell anything though, so I left it. Ella persisted with her digging motions so I finally had to wash the rug and mop the floor. I don't know why she doesn't go to my wife with this stuff.