Keep cats separate at first.,
Introduce them by smell.,
Introduce them by sight.,
Switch their positions.,
Allow them to interact.,
Feed them around each other.
Try not to let your cats even come into contact on their first few days. Put the newcomer in a small room by themselves. They will more comfortable in the smaller confines, and they will be unable to come into contact with your current cat. Start by doing this for seven days.This is a slow acclimation process, and you may have to repeat it.
Don’t ignore your old cat when you get a new cat. This can cause your old cat to hate the new cat and feel sad.
, Allow the cats to smell each other under a door, but do not let them have physical contact. Bring toys or bedding that both cats use to allow the other to become accustomed to the new scent. This will help the cats get used to the idea that there is another cat around.
Help your new cat to acclimate to the scent of the old cat using footwear. After a couple days have gone by, rub a small clothing item (such as a sock) all over the old cat, to pick up its scent. Then place it in with the new cat. Watch the reaction. Hissing is normal, but if the new cat is okay with the old-cat-scented sock, praise the new cat and give it a treat.
Some behaviorists suggest rubbing the cats separately with the same towel to intermix their scents. First gently rub one cat with the towel. Then rub the other cat. After the towel carries both cats’ scents, bring the towel back to the first cat and rub her with it again , Don’t let them come into physical contact. A child or doggy gate will work to separate them in this case. Watch how they interact. Does their body language indicate distress, or do they seem calm and accepting of the other? These signs will inform you as to how long the process should take. Calm, friendly cats do not require as long an acclimation process as ones who exhibit aggression.
Stack two baby gates on top of each other in the doorway to the new cat’s room, to ensure neither cat can get to the other.
Let your old cat discover the new cat in the room on its own.
If they both have non-aggressive reactions, praise them and give them a treat. If not, shut the door and try again some other time
Keep the gates up for a while. You can leave the baby gates up and the two can meet and greet as they please.
Watch for defensive postures
Head tucked in
Tail curved around the body and tucked in
Eyes wide open with pupils partially or fully dilated
Ears flattened sideways or backward on the head
Piloerection (hackles up/hair stands on end)
Turning sideways to the opponent, not straight on
Open-mouthed hissing or spitting
Might deliver quick strikes with front paws, claws out
, After some time, place your old cat in the room where you kept the new cat, and vice versa. This will let your old cat examine the smells of the new cat, and it will give the new cat a chance to be more familiarize itself with the space from which it was previously excluded. Do this a couple times, before proceeding in the acclimation process., Once they’ve had time to adequately acclimate to the new situation, let them come into contact with each other. Keep a spray bottle handy, in case of aggression. If your cats get along fine, you may be ready to let them both roam free. Even still, pay close attention to their behavior. The key to having a multi-cat household is preventing territorial aggression.Place them both in a room where you can supervise.
Only allow them about ten minutes or so for the first meeting. You can gradually increase it as the days go on, but you don’t want them to become agitated.
Introductions can take weeks, or they can take months. The important thing to remember is to go at the cats’ pace. It may be slow, but it’s worth it if your cats will live together in peace.
Never physically punish your cat(s) for something like hissing or fighting with each other. This is a very common reaction. If one cat starts being aggressive pick the other cat up instead. And always make sure they are not just play fighting, these can be hard to tell apart.
Watch for offensive postures.
A stiff, straight-legged upright stance
Stiffened rear legs, with the rear end raised and the back sloped downward toward the head
Tail is held straight and stiff, like a classic Halloween cat’s posture
Upright ears, with the backs rotated slightly forward
Piloerection (hackles up), including fur on the tail
Directly facing opponent, possibly moving toward him
Might be growling, howling or yowling
, When cats are eating from a bowl of food, they are in a non-aggressive state. By feeding them together, even across the room from each other, they get used to being non-aggressive when the other is present. Treats when both cats are calmly together can also help to reinforce good behavior.
Every time the cats see each other, give them treats. They will associate “treat time” with each other and feel the positive benefits of being around each other. It also shows them that they don’t have to compete for food or attention, and that enough is provided for both of them.
If the cats won’t eat, or become aggressive, they are probably too close together.
If they eat and seem relaxed, they can be moved closer together at the next feeding session.
This whole process can take weeks or even months. Signs of anxiety or aggression usually indicate that the introductions are proceeding too quickly. Address signs of outward aggression:
Swatting, striking with paws
Preparing for an all-out attack by rolling onto side or back and exposing teeth and claws.