The following technique can be used to introduce a new kitten or cat to your other cats. I have been involved in pet rescue for most of my life and this technique worked successfully every time. Over the years, I have had to make some modifications when introducing older males or feral cats, but in most cases this will work exactly as described. Your pet is assumed to be neutered and the new pet is neutered or less than six months old.

If you have a choice, you may want to follow the recommendation of a “wife’s tale” and choose a new young cat who is the opposite sex to your pet. For example, if you have a neutered male, select a kitten or a young female. If you have an older female, select a young male kitten. Many people believe that these combinations are the best options to ensure a compatible combination. There is some biological support for this argument, but I have fused many cats of the same sex and of the same age and it has always been successful.

1. Before bringing a new kitten or cat home, make sure it is free of communicable diseases: feline leukemia, distemper, rabies, worms, and fleas. Most people avoid adopting a cat that has been exposed to Feline Aides, but there is a mixed jury on how Feline Aides spreads. You may want to read up on this topic and form your own opinion before considering merging a cat exposed to IVF with a healthy cat.

2. While the cats are still in separate places, give both of them a large meal. For example, give both cats a meal that is comparable to our Thanksgiving dinner; options include your favorite canned food, sardines, tuna, or chicken. Give them at least half an extra serving. You may also want to give him some relaxing natural herb as a “Rescue Remedy.”

3. Place the new cat or kitten in a cat carrier about half an hour after the cats finish eating their large food. Ask a friend to bring the new cat or kitten home and place the carrier in the middle of the living room floor; Make sure there is a place where the new cat can hide once it comes out of the cage (i.e. a couch, meat, etc.). If you cannot find a friend to bring the carrier, you can do it yourself, but you must ignore the new cat at all times.

4. Let your cats smell and hiss with each other with your cat loose in your house and the new cat safely inside the carrier. Since both cats are full and relaxed, it may take 20 to 30 minutes before the cats are noticed.

5. One hour after bringing the new cat inside, open the door of the carrier, but ignore both cats. Let the new cat out when it feels ready; this can take up to 30 minutes. Cats can keep hissing and yelling at each other, but it’s usually pretty minimal. Most of the time, the new cat will look for a safe place to hide, such as under a sofa or chair. If the new cat runs towards you, ignore it.

6. For the next 3-4 days, you must ignore the new cat. Allow your cats to yell and hiss at each other whatever they need. This allows your current pet and the new pet to establish their own hierarchical order. The only time you would want to interfere would be if cats fight badly. If this happens, pour a large amount of cold water on both cats and start the process again. (I had to fuse two sickly old male cats once. They had both been “Tom” cats for years. After this hour-long fusion technique, they got into a horrible fight. I broke the fight with water, got a big cage for dogs and for two days I rotated which cat was in the cage and which cat got loose. After two days, these cats got along very well).

One final thought, you may want to start the introduction at a time when you can be home for a few days. For example, if you work Monday through Friday, you may want to combine the cats on Friday night so that you can observe them over the weekend.