Whether you are adopting from an animal shelter or rescuing a cat off of the streets, bringing home a new cat can be both exciting and stressful depending on how successful the initial introduction is between the new cat and resident cat(s). Even though cats are social creatures, keep in mind that by nature, felines are extremely territorial and generally do not like sharing their space with other felines, but the good news is, with patience and time, felines do indeed adjust very well to change. One of the biggest mistakes cat parents make when introducing a new cat to their resident cat is putting them in the same room together without giving them a chance to get to know each other, which results in a lot of hissing, chasing and fighting. Just as people need time to adjust to living with one another due to the difference in personalities, kitties also have different personalities and need time to adjust to a new cat living in their home.
Before you bring home your new kitty make sure you have designated a room or safe space in your home that will keep her away from the other resident cat(s) to ensure her safety and make her feel comfortable. As soon as you bring the new kitty home be sure to keep her in the cat carrier and immediately bring her to the room you designated for her and keep the door closed. Once she is safely in the room with the door closed away from the other cat(s) in your home, let her venture out of the cat carrier on her own, giving her time to get used to her new surroundings and smells. Cats have an advanced sense of smell and can easily detect the presence of another cat which is very helpful when cats are being introduced to each other. After she comes out of the cat carrier, you can place the empty carrier in another part of the home where the other cat(s) are so they can get used to her scent.
Keep the new cat separated from the other cat(s) for a week or longer until you think they have gotten used to each other's scents. At this point there are several ways to make the first face-to-face introduction but the easiest way to do this is to put the new kitty in the cat carrier with the latch fastened securely and bring her into the living room and set the carrier on the floor, but DO NOT unfasten the latch to the carrier. The other cat(s) in your home will curiously walk towards the carrier and stare at the new cat and smell the carrier, immediately recognizing the scent of the new cat. Keep doing this introduction routine for another week or so until you feel comfortable enough to let the new kitty cat be in the same room with the resident cat(s) without the protection of the carrier. Be sure to supervise their interactions and pay very close attention to their body language and hissing if any and if you notice aggression immediately separate them and repeat all of the introduction steps over again.
Time and patience is definitely key when introducing cats to each other so don't give up or feel defeated if it takes more than a month for the new kitty to be welcomed by the other cats(s) in your home. Also keep in mind that some cats might never become the best of friends, but in time, some learn to tolerate each other by avoiding confrontation. To learn more helpful tips about introducing cats to each other please contact the Treehouse Humane Society, Harmony House for Cats, Felines & Canines, or PAWS Chicago.