Animal Chronicles
Spring & Summer 2008

Why Does My Cat Do That?
Introducing a new cat to your resident cat

by Laura Hazard

Properly introducing a new cat to a resident cat can be challenging, but with a little planning and patience you will likely be rewarded with a harmonious household. Throughout this process, it’s helpful to remember that although many felines enjoy each other’s company, cats are biologically predetermined to perceive each other as competitors. Consequently, the resident cat may see a new cat as a threat to his territory. This does not mean they won’t become companionable, it simply means that introductions should proceed slowly, while reassuring both cats that they are safe.

Before bringing a new cat into your home, divide your house into sections so that each cat has a room (or safety zone) which the other cat is not able enter. If possible, the resident cat’s safety zone should be your bedroom or a place where your cat likes to sleep. The new cat’s safety zone can be another bedroom or a bathroom.

Don’t be surprised if your new cat feels the need to hide in her room for a while. Hiding allows the cat to regulate her anxiety and it’s perfectly normal for a cat to hide, come out and then hide again. Let your new cat become comfortable in her room for several weeks. During this time, concentrate on building a relationship with her.

Long before your new cat explores the rest of the house, your resident cat will be aware of her presence. He is going to react, possibly negatively. Remember that just because your resident cat has been known to like other cats in the past, this is not a guarantee that he will appreciate all cats. Domestic cats are closely related to wild cats, which means that when competition for resources is perceived, a “fight or flight” response naturally occurs. In this case, the resources are you, your family and the house. So when the two cats see each other, they will size each other up, and often, one will try to make the other go away. We want to avoid that moment, and we can accomplish that through this slow introduction.

After your new cat has learned to feel comfortable in her safety zone, let her explore the common areas of the house. Put your resident cat into his own safety zone during this time. This allows the two cats to smell each other without making eye contact.

After several weeks of exploring the common areas, rub each cat with a towel. Rub especially under the chin where the scent markers are non-threatening. Then give the cats the others’ towel, leaving it on the floor in their safety zone— continue to leave the towel there for a few days.

At this point, you can take a break and allow the cats to chill out for a few days in their respective rooms. During this time, reassure them that they are safe and loved. When they are ready, switch their safety zone for a few hours again. Then give them back their original rooms, but make the common room open to both. Offer hiding places in the common rooms and keep the doors open to the safety zones so they can run away if needed. More than likely, one cat will be the aggressor and will chase the other back to their room. If you can, avoid letting the other cat enter that room.

Taking a few months to introduce two cats to each other may be inconvenient, but in the long run, you will have better success. Taking this time will help avoid bigger issues like marking and urinating outside the box, and hopefully, will create a loving friendship for you and your cats.

Laura Hazard is the Marin Humane Society's cat behavior consultant.

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