DEAR JOAN: We have a 1-year-old male kitten and a 5-year-old female cat. Unfortunately, they don’t get along.

I made the mistake of buying a new bag of litter. It was black; I had no idea. We have a Litter Robot that I love and they used it with no problems until they got the new litter. Then they decided they didn’t like it.

I replaced it immediately. The cat is fine, but the tomcat uses it from time to time and uses the extra litter box I put in, but sometimes he does his business right next to the litter box.

He’s been to the vet and he’s fine. The vet gave him Valium and that helped, but why did this happen? When he started using the Litter Robot again, why didn’t he use it all the time?

Lucinda Lawson, San Jose

DEAR LUCINDA: Cats will be cats.

One of the worst things we can do to these sweet little creatures of habit is to change something they are used to and like. Cats are very picky about their litter, preferring a certain texture, look and smell. Your little boy obviously liked the old litter and was stunned when he stepped into the litter box to do his business and found things were not as he expected.

I can actually understand that. I like my routines too. It was smart of you to make a change right away, but it seems that the whole episode unsettled your cat so much that she had trouble going to the bathroom.

The trust between litter box and cat has been destroyed and it will take time to rebuild it. For heaven’s sake, don’t make any more changes, like moving a vase a few inches to the left, and he will eventually learn to trust his litter box again and adopt some other incomprehensible behavior just because that’s what cats do. And we love them for it.

Help for a cat that aims too high

Last week I reached out to a reader who was having trouble with his cat sometimes overshooting the edges of his litter box. I’ve received many emails from people who have had the same problem.

DEAR JOAN: Rick could try building Will a litter box out of a garbage can, like in this video. If a litter box isn’t long enough for a cat, it will sometimes hit the sides, probably because its tail can’t comfortably reach down any further. The litter box should be 1.5 times the length of the cat, measured from the nose to the base of the tail.

Jennifer A. Woolf, DVM, MS, Woolf Veterinary Forensics Consulting, Inc.

DEAR JENNIFER: Thank you for this very helpful information. Many people wrote to us saying that they dealt with their stray by getting a larger litter box, often building it themselves.

Other suggestions include a litter box with an opening at the top. Many people have built their own litter boxes out of plastic containers or even a baby bathtub.

One reader recommended the Mod Kat box (modkat.com), and another reader increased the height of the box by adding plastic walls to a regular litter box. One person recommended a San Francisco-based brother-sister company (www.peepeeshield.net/) that invented and sells pee shields for litter boxes.

Another cat lover places her litter box on a large planter filled with litter to catch any mishaps.

Thanks to everyone who sent suggestions.

The Animal Life column appears Mondays. Contact Joan Morris at [email protected].