How to Properly Introduce Cats
So it's finally happened, the big decision to get your kitty a new friend! This is a good idea for several reasons, however without the proper introduction, it could turn sour very quickly. Let us help you out!
Know your current cat well. When trying to find them a friend, try to find one with a similar personality, so they can cuddle and play well!
Keep your new kitty separate from your old one. Cats are very territorial, and simply throwing a new cat into a space that your old cat already considers their own can be risky. Put your new kitty in a bedroom, office, or bathroom and keep the door closed. Fill this room with everything that your new kitty needs: food and water dishes, a litter box, toys, scratchers, and beds! Make this room the perfect haven for a new kitty to live in. Once your new cat is settled in their room, remember to spend lots of time in there with them, playing and cuddling. The closer bond they have with you, the faster they'll become comfortable with their new surroundings.
Allow your kitties to meet each other through scent! The easiest way to do this is to feed your cats on opposite sides of the door, your new cat inside the room, and your old cat outside. This allows both cats to create a positive thought associated with the smell of the other cat (this smell means I get food! Yummy!). Also allow your kitties to smell and paw each other beneath the door.
An additional tool might be the use of Feliway scent diffusers, which emit an odourless copy of the harmony marker pheromone and helps maintain a harmonious bond between cats.
This step will only happen when your new kitty shows they are ready. When your new kitty is ready, do a site swap! Allow your new kitty to roam and explore the rest of your home (do this slowly, one room at a time, if new kitty is shy or nervous) and put your old kitty into the new kitty's safe room. This allows both of your cats to get to know the other's smell better. If this isn't possible, then simply swap out a bed or scratcher, and allow your cats to scent swap that way.
This step will start once your cats seem to do well with the other's scent. Find a way to introduce your cats visually, without allowing them to physically interact. Use a gate or a screen, and if that isn't possible, simply open the door between them a crack, and supervise to ensure they each stay on their own side of the door. Keep the interactions short, to ensure the lowest stress levels, and lower any risk of fights breaking out. If your cats respond well to each other visually, increase frequency and duration of these interactions. If they respond by hissing and growling, maybe take it back to the scent swap stage for a few more days.
Introduce your cats to each other physically! Wait until they are responding well to visual introductions before introducing them physically. Allow both cats to interact in the same room, but make sure to keep them both entertained, either with cuddles or play, to ensure that neither one gets bored enough to attack the other.
Once they seem comfortable with each other in the same space, you're all finished! Remember that this process can sometimes take weeks, or even months depending on your cats' attitudes and behaviours. Most cats can actually take up to a year before friendships can be formed, and sometimes the best you can get is tolerance, which is still better than fights!