What is the best way to get a new cat used to an existing cat and its litterbox?

Answer 1

Keep the new cat separated from the existing cat for a period of three-ten days, making sure it has its own food, water, litter box, toys, etc.... The length of time to keep the cats separate is totally dependent on how the new cat adjusts to its new home and owner. If it adjusts quickly, you can start the next steps in the introduction process earlier - but, for example, if it hides under the bed for its first two days and then rarely comes out, you'll have to wait a lot longer. Be aware that because cats have a much better sense of smell than humans, both cats in the scenario will totally know the other cat is there, even if they don't see each other - they can pick up each other's scents.

Once the new cat is settled, you can start the introduction steps.

1. Switch the two cats for 10-15 minutes - put the existing cat in the isolated room and let the new cat roam the rest of the house (and make sure one room it checks out is the one with the litter box). Once they are back in their own spaces, reward them with a treat. Do this three-five times over the next few days.

2. It's now time for them to see each other. It is best to do this with two people, one for each cat. Take the new cat out of the room and bring it to the room where the existing cat is. Keep them eight-ten feet apart, but definitely make sure they see each other. The first time you do this, do it for five minutes or less. Give them both a treat when it is over. Do this two-four more times over the next few days, lengthening the time they are in the same room a little bit each time.

3. Assuming the room visits went fine, you can now let them interact, but only with supervision. Bring the new cat down to the room where the existing cat is and let it go. If they get into a fighting stance right away - the best way to know is to watch their ears - if they go down and there is a bunch of hissing and growling, separate them and go back to the visits a few more times. If they interact well, you can let them be.

There will almost certainly be some amount of hissing and/or fighting (either real fighting or play fighting) in the first few days as both cats figure out their new territories - this is to be expected. But again, if the hissing and fighting gets ugly, separate them.

And as for the second litter box, your new cat will decide where it wants to go. It might continue to use the box in the room, it might switch to the existing box, or it might use both. Your existing cat might start using the new box, too. People think that cats should be able to share a litter box, and some do with no problems. But many do not, for a variety of reasons, including territory issues, cleanliness, location of the box related to where the cat likes to hang out, etc.... Most experts recommend at a minimum one litter box per cat, and many would actually recommend an extra one.