How stressful were the introductions? And, did the cats really become friends or did they merely divide up the territory and draw a line in the sand? Just because these cat parents don’t see overt aggression doesn’t mean these cats aren’t living under constantly stressful conditions. Why would you want to use a technique that puts all cats involved at risk? Well, that’s optional if one cat eventually licks another.
Hopefully, the tasting aspect won’t involve any biting though. From the resident cat’s perspective, there’s an intruder in his territory. From the newcomer’s point of view, she has just been dropped on hostile turf. Both cats need to feel secure. If they feel as if there’s no safe place for them, that’s when they’ll revert to survival mode and you’ll see panic, fighting and perhaps spraying. If, however, they feel they can remain in their comfort zones while checking out the situation, you can usually keep a lid on the panic button. Both cats need safe areas to decompress during this life-changing event — and it is a life-changing event.
Your resident cat doesn’t understand why he no longer has the entire territory to himself and the newcomer must get to know an unfamiliar territory, unfamiliar humans AND an unfamiliar cat. Set up a room to be used as a safe place for the newcomer. This gives her time to get somewhat familiar with her new surroundings in a more secure way. It’s stressful enough for a cat to move to an unfamiliar environment so before you attempt to introduce her to your resident cat, let her get her bearings and have time to herself in a sanctuary room. You don’t want to even attempt an introduction with a reactive newcomer so the sanctuary gives her a place to get herself back to normal functioning level. The more relaxed each cat is, the better the chances of a successful introduction. The sanctuary room can be any room you can close off.
If the newcomer kitty is timid or fearful, being able to stay in the carrier containing her own familiar scent may provide much needed comfort in the beginning. For a fearful cat, set up some paper bag tunnels as safe ways for her to get to resources. That way, she can get to the litter box or food without feeling too exposed. Put other hiding places around the room for her as well, such as upside-down boxes with entrance holes cut in them. This may help her feel as if she doesn’t have to remain hidden under the bed or in the closet. If she spends her days cowering under the bed and wedged behind your suitcase in the closet, she’ll be too frightened and reactive and that will lead to an unsuccessful and extremely stressful introduction.
I Know You’re in There! Even though your resident cat won’t be able to see the newcomer, he’s going to be aware of the fact that she’s on the other side of the door. This is normal but by having the newcomer in the sanctuary, you’re letting your resident cat know that only a portion of his territory has been invaded and not the entire home. You can’t just separate them for an extended period of time and then open the door expecting them to magically form a bond. They’ll need to see good things happen when they’re in the presence of each other, and later, within sight of each other. The best way to do this is with food and treats. Food is a powerful motivator!
How far from the door itself will be determined based on the reactivity level of each cat. If your resident cat won’t come within six feet of the door then place his food bowl well within his comfort zone. In subsequent sessions you’ll gradually move the bowls closer and closer to the door itself. Don’t offer too much food during each training session. It’s better to do frequent sessions that are short and that end on a positive note. This is the method I came up with many, many years ago and has been very successful with new cat introductions.
It’s very simple and it starts with a pair of clean socks. Pheromones are scent chemicals that are released from a cat’s scent glands. Cats facially rub on objects in locations where they feel comfortable. So by using the sock, we’re going to create a simulated cat that contains lots of friendly pheromones. Place the scented sock in your resident cat’s area. This will give him a chance to do his own initial investigation of the new cat’s scent. Let your cat do his own investigation. I click and reward any positive move the resident cat makes toward the sock. I click and reward for merely walking toward the sock. I click for anything I would like to see the cat do again and I ignore any negative behavior. For example, if the cat sniffs the sock I click and reward. If he walks by the sock without giving it a second look I click and reward. The reason I use the sock is that it gives the cat time to get to know the other cat’s scent in a safe and controlled way. The cat doing the sniffing can safely approach and I can do behavior modification without worry that one or both cats will get injured.