In extremely rare circumstances will cats who are strangers immediately “like” and accept one another. In most cases, there is bound to be some animosity and because of this it is key that cats are introduced to each other in stages and not just left together to “get on with it”.
The best time to bring a new cat into your home is when there isn’t much else going on, for example doing the introduction at the same time that you have overnight visitors staying over would not be a good idea. The “resident” cat needs to be relaxed, and you need to have enough time to manage the introduction process.
Cats will always get on better if they don’t feel that they have to compete for your attention and affection, or even over their “resources” such as their bowls and litter trays.
In general, kittens are always less of a threat to adult cats than another adult cat, and a cat of the opposite sex may also be more acceptable to a resident cat.
You may wonder why on earth your cats mingle with each other by smelling each other’s nether regions, but this is actually how cats communicate: by scent. In the same token, this is the best way to let your resident cat meet the new arrival.
The best thing to do would be to keep the new cat in a safe room, separate from all resident animals. Give both of them plenty of love and attention, but the key here is to then go to the other cat without washing your hands and stroke the other cat so that their scents mingle.
After a day or two, allow the new cat to start exploring the rest of the house while the resident cat is in another room with the door closed. Continue to allow them separate access to the house for a week or two.
Then it’s time to make the introduction. This would be another stage in the process, and the ideal way to do this is to place the new cat in a carrier above floor level so that the cats don’t make direct eye contact. Direct eye contact in cats that are strangers to each other is an immediate show of aggression, so you want to avoid that.
Let the resident cat discover the new cat in its own time. Of course there will be some hissing and glaring but you can distract the cats during this process by making a noise, remaining calm, and most importantly by praising more accepting behaviour, even giving treats to reward them. Always remember to make an extra effort to fuss over the resident cat.
After you’ve done this a couple of times, let the cats eat near each other – again with the new cat in its carrier and the resident cat on the outside. This process could take a few days or a matter of weeks depending on the personalities of the cats involved.
You will know when the time is right to move into the final phase of the introduction. Make sure that this is done in a room where the one can hide or get up high if necessary. You can use food as a distraction, feeding the resident cat first and then the new cat.
Always remember to stay calm and feel free to reward positive behaviour.
As time moves on you can let them spend more time together, or, if there is still animosity, keep them apart for longer.
Be patient, cats, like people, eventually learn to get on in the end.
– Article posted by Phillipa Mitchell.