Introducing a new cat

Some cats can be very social and can fully enjoy living together with other cats. Other cats like to live as only cat in the house. If you introduce a new cat to one or more cat(s) which was/were already present earlier, realize that they need to get used to each other and that this takes time. Most cats need 8 months until one year before a friendship arises. Other cats never become friends but tolerate each other by simply avoiding each other. You also have cats which keep on fighting, so that your only choice will be finding a new home for one of them.
Do you have one or more cats which in the past always lived together harmoniously with other cats; you will have a good chance then that this/these cat(s) will perfectly adapt themselves to a new cat in the house. But you can never predict in advance if certain cats will get along. If your present cat reacts aggressively on other cats outside, then it will probably become difficult to introduce a new cat. Unfortunately there are no reliable guidelines in order to be able to predict which cats will get along or which won’t. We do know that tomcats, in case a friendship arises, incline to spend more time together than female cats. But the individual personalities of cats are more important than whatever factor. Be aware of it that the number of conflicts between the cats will increase if you take more cats in your home.

The first day of the new cat
The first impression which your cat makes on the other cat(s) is very important. Should the cats show any aggression, this might then be an omen for the future relationship between them. For this reason it might be better to first keep the cats separated, in such a way that they can smell and hear each other but are not able to see or touch each other. Each cat must have its own trough and waterbowl. It is also better to give each cat an own scratching-post, cat box etc. Feed the cats near to a closed door which separates them from each other so that they will learn (even though they cannot see each other) that it is pleasant to be with each other. Also feed them with delicious snacks here like salmon, cheese and chicken. Keep on doing this the first 2-3 days.

After 2-3 days
You can now “rotate” the cats. You switch places. You place one cat on the other side of the door wheret he other cat used to sit. The cats can now investigate each others smell (some behavior experts claim that it is even good to rub the cats with a towel which has the smell of the other cat on it). Besides the new cat has a chance now to discover an other part of his new surroundings. Approach the concerning door after you have played some days with the cats. Encourage the cats to push a little toy under the door. It might happen that they start playing together with the toy.

After about one week:
If you don’t observe any aggression (blowing, growling) you can replace the door after one week by a temporary, transparent screen or a door with a large window so that the cats can see each other. Keep continuing placing the food and snacks close to this door. In the beginning some food beyond the door and little by little a bit further.
 

Finally together:
In this phase the cats can finally spent some time together. Start with short periods of 10 minutes and watch them closely. The best way to start is bringing them together on a moment that they are usually very quiet, like after diner or after an extended play session. Make sure you have a plant spray around in case they start fighting. If the cats are used to each other you can extend the periods of being together. Should one of the cats keep hiding himself or continuously bothers or chases the other one, you should consult a behavior expert. Observe your house lay-out in advance. Be sure that there are enough spots where the cats can hide or withdraw. Some cats like to sit on a high spot for example on cupboards. Scary cats are inclined to hide things, be assured that you have enough hiding-places on floor level. Place the food, drinks and the cat box in an open space, so that the cat doesn’t feel caught if he wants to come here. Good luck!
* This article has been written in the “he” form for the readability. It goes without saying that “he” or “him” can be replaced by “she” or “her”.