The following technique can be used to introduce a new kitten or cat to your other cat (s). I have been involved in pet rescue for most of my life and this technique worked with success every time. Over the years, I had to make some modifications when introducing older males or feral cats, but in most cases this will work exactly as described. It is assumed that your pet is neutered and that the new pet is neutered or less than six months old.
If you have a choice, you may want to follow a “wife’s tale” recommendation and choose a new young cat that 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 match. There is some biological support for this argument, but I have fused many cats of the same sex and 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, feed them both 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 a half extra serving. It can also give you some natural herbal relaxation 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 big meal. Ask a friend to bring the new cat or kitten into your home and place the cage in the middle of the living room floor; Make sure there is a place where the new cat can hide once he is released from the cage (i.e. a couch). , meat, etc.). If you cannot find a friend, you can bring the carrier yourself, but you must ignore the new cat at all times.
4. Let your cats sniff and hiss with each other with your cat loose in your home and the new cat safely in the cage. Since both cats are full and relaxed, it may take 20-30 minutes for the cats to notice each other.
5. One hour after bringing the new cat inside, open the carrier door, 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 should ignore the new cat. Allow your cats to yell and buzz at each other as much as necessary. This allows your current pet and the new pet to establish their own hierarchical order. The only time you want to interfere is if cats fight badly. If this happens, throw 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 interrupted the fight with water, got a large dog cage, and for two days I rotated which cat was in the cage and which cat was loose. At the end of the 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 can combine the cats on Friday night so that you can observe them over the weekend.