These types of introductions need to be carefully managed so as to avoid creating negative associations which are hard to shake off. First I’ll explain more about how Feline Hierarchies work in comparison to other animals.
A dogs hierarchy system is called ‘absolute’ and consists of each individual having a place in the system which is in force in all situations until they win a better place or are demoted by another individual.
Cats use a different system called a ‘relative’ hierarchy. This is where each individual has a different position depending on time, place, and situation. In this type of hierarchy, there is a top cat who will be ‘in charge’. The selection of this ‘top cat’ is not as black and white as with dogs since there will be different leaders with different responsibilities depending on the situation and environment.
For example, amongst my indoor cats, Grace is the leader and will be the one who investigates anything new and exciting. It is not always the biggest and strongest cat who becomes the boss. My cats are a prime example of this Grace being a small female and setting the rules for my much larger and younger male cat.
The purpose of the hierarchy is to make sure that the cats work with as little aggression as possible when sharing the same environment.
1. A ‘safe place’ & confidence building
I have explained this technique in some detail in my post on How to settle a nervous newcomer, but the basics are to base the new cat in a room not favoured by your resident cat and keep him/her isolated in there. When your new cat is comfortable and confident in their room, start feeding both cats on either side of the closed door. Don’t put the bowls right up against the door just close enough so they can sense each other.
This will help them both to associate something they like (eating) with each other’s scents. Slowly move the bowls closer to the door each meal time until the cats can eat calmly on either side of the door. Another way to encourage non-visual interaction is to encourage the cats to play with a shoelace or something similar under the door. This initiates play between the cats without actually coming face-to-face and results in a more positive association.
2. Scent swapping
While your cats engage in non-visual segregated contact, you can do a few things to help them get used to each other. Swap sleeping blankets between your resident cat and the newcomer, or rub a soft towel on the new cat and then place it somewhere in the room where the other cat can sniff it. Once your new cat feels relaxed and at home, allow him to explore the rest of the house while at the same time allowing your other pet to visit the new cat’s room. Keeping them separate at this stage with the door to the ‘safe place’ room closed. To a cat, scent is more important than sight in the first few days.
This swapping of possessions and environment allows the cats to experience each other’s scents without a face-to-face meeting. It also allows the new cat to become familiar with his/her surroundings without being frightened by the other cat.
3. Face to face
The final step in the introductions process is a face to face meeting. This can take a long time and sometimes the above steps may need to be repeated several times until the cats are comfortable enough to be together. The best time for a face to face meeting is at meal times. Feed both cats at the same time but place the food bowls a distance apart (opposite ends of a room). Hissing and growling is normal as is some swiping.
It is very important that you do not intervene between the two cats even if they show signs of aggression. You should instead carry a towel of water squirter which you can use to distract the cats in case the meeting goes south. If either cat shows signs of fear or physical aggression, separate them immediately and try again when they are both calm (the next day).
As I said some growling and hissing is to be expected at these first meetings – this is all part of establishing the new hierarchy. Once they get used to each other, they can spend more and more supervised time together in the same space. They should not be left alone with each other (even at night) during the first two weeks, but this may be longer depending on how well the introductions goes and how quickly it progresses.
When the introduction process is done correctly, and slowly this is rarely a problem. Most cats will learn to get along together, and even if they don’t become best buds, they will tolerate each others presence.
Aggressive behaviour can become learned, so it’s important that you try to prevent it before it escalates. Stop any fighting before it starts by reading their body language. Try to distract your cats with a loud noise, even a hissing sound similar to a cat’s, or by throwing a toy in the opposite direction. If necessary, separate the cats until they have calmed down.
If a fight does happen then use one of the distraction techniques above to break it up, then remove the aggressor and hug and kiss him/her, rather than the victim cat (even though you feel sorry for them).
You can help reinforce the ‘top cat’s’ status amongst your other cats by doing things like brushing him/her first, feed him/her first, say hello to him/her first. This will allow the ‘top cat’ to reinforce his/her status, making any further conflict less likely.
It’s important to provide each cat with a space of their own in a multi-cat household. This could be a room or event a favourite spot within a room. If each cat can get some peace and quiet without being disturbed by another, then this makes conflicts less likely. Make sure you have enough resources for each cat, a food/water bowl, bed, litter tray and toy(s) each. It’s also a good idea to have an additional litter tray if you have space.
Things to help
Feliway spray or diffusers help cats to feel calm and relaxed and can be very helpful when bringing a new cat into the home. You can get Feliway products from your vets or at most local pet stores.