The first thing to know is to be patient. It is not as simple as with dogs because dogs are less picky to make new friends. For cats, a new inhabitant in the house is extremely stressful situation. It requires a change in the dynamics of their territory and this creates a great tension.
Although cats are sociable, they also are territorialists. This does not mean they are unable to share their environment, but they are more methodical. However, many people put them together and let them know each other. This may actually work, but it is a very risky technique. The stress levels increases the risk of fight between them. Moreover, you can end up with cats who do not support themselves and do not share the same territory.
The same goes for puppies. It is not because they are small and harmless that they do not stress. The process should be done with both sides relaxed and you should never force the situations. Check out the step-by-step.
Step 1: The sanctuary
For the new cat, this change in routine is stressful. He will need to get used to the new environment so he can relax. Separate a room for the newcomer, who will stay with closed doors. In this place, put everything a cat needs such as food, water, sand box, toys, and places to climb and to hide. Provide plenty of places so he can hide and relax, he needs to feel safe. The other cats in the house are forbidden to visit this sanctuary.
All the cats in the house already know there is another different cat in the environment. If they stand in the doorway of the room, snarling or yowling, never tell them off. Try to distract them and get them out. They also need to relax.
Step 2: The Delicious Training
Both sides need to know this change is not bad. We need to give a reason for cats to like each other! Food and snacks are great rewards. The idea is to provide meals for all cats at the same time, on opposite sides of the sanctuary room door.
The distance between the bowls will be defined by the permissiveness of the cats. Gradually approach the bowls until they are next to the closed door, one on each side. The speed you will approach the bowls depends on the reaction of your cats. Be patient. Prefer several short feeding sessions per day. The number of sessions depends on your routine.
Food and snacks are great rewards.
The food you will offer depends on what your cats routine is like. If they have food at will, give small amounts of wet food, they will love it. The main thing is to avoid going beyond the limits and avoid stress.
Step 3: Time to Sniff
Cats recognize each other through the smell and this is what gives each one's identity. Animals release different odors when they are afraid, relaxed or happy.
Thus, we can introduce two cats rubbing a towel and offering the other to sniff. Take a clean towel, and rub the new cat's fur when he is calm and relaxed. Put the towel in the other cats' environment. Leave it on the floor and reward them every time they show good behavior such as to smell and stay calm. Do this same process with the other cats.
If anyone exhibit unfriendly behavior, do this procedure until he become used to the smell. Only move forward if everyone is comfortable and receptive.
Step 4: Changing environments
It’s time to let the new cat know the house. Put the former residents in another shortly locked room. Open the door of the sanctuary room and allow the new inhabitant to explore the house. Keep snacks and toys on hand to distract him if necessary.
He may not want to leave the sanctuary. If this happens, be sure to repeat this step until he is receptive to the new environment and be as comfortable as in the sanctuary. Always reward good behavior. You can also put the old cats in the sanctuary without the new cat there.
Step 5: A little Spy
Once the new cat is already used to the environment and the former residents are used to the new presence, it is time to they see each other for the first time. Open the door of the sanctuary and let them look at each other. Initially, the spy time should be small. Try to do short sessions with positive end. Increase time gradually, according to the receptivity of all involved.
If any side is stressed, try distracting them with a toy or snack. You can move on when they simply ignore the other cat's presence.
Step 6: Time to approach
It is time to open the door of the room totally. Remember having always in hand the snacks and toys to distract them. Do not leave them alone for the first moments. In general, try to keep the interactions as positive as possible. Increase the time of coexistence gradually.
If cats start to fight, then separate them calmly. Do not tell them off, just gently get one of them on your lap. So always, have a towel on hand to be able to intervene without getting hurt.
Patience prevents failure
The hint for a quiet process is to have a lot of patience. It is not a quick and simple procedure. Speeding things up increases the chances of failure. It can take weeks or even months, for you to make everyone feel good about each other. Even so, the cats may not be friends. Fellow cats sleep together and bathe each other. If your cats do not do this, they just tolerate each other. However, sometimes that is all we may get. The important thing is to have a calm and nice place to live.