New Arrival: Bringing a New Cat into Your Feline Household

Interested in adopting another cat? Before you act, think carefully, consider your household and ask yourself, “How many cats is too many?”

How Many Cats?

Will an additional cat fit into your household? The answer depends on the size of your home, the number (and temperature) of existing feline residents and your own expectations. Some cats are naturally more sociable than others. Some are content to share a small space with others. Others want to control everything they see.

As a general rule, the more cats you put in a confined space, the greater chance of a problem behavior. Bear in mind, however, that most of what we perceive as “problem” behavior is perfectly normal for cats. Cat society is a delicate balance of solitude and sociability. When you confine several cats to a small space, some may feel that others have invaded their territory. These cats may respond to a new shared living arrangement by fighting, hiding, house soiling, or demonstrating other behavior that you find unacceptable in your home.

Choose the Right Cat

If you decide that your home can support another cat, try to choose one with a sociable temperament. The cat should be confident, friendly, and not overly aggressive around other cats. If the new cat is coming from a shelter, your best clue as to how it will get along with your cats is how it behaves toward the other cats at the shelter.

Some owners believe their cats will accept a kitten more readily than an adult cat. Indeed, many cats find a kitten less threatening than an adult, but there is no guarantee that your cats will get along better with a kitten. A sedentary cat may not appreciate a kitten’s youthful exuberance. A mature cat may adjust better to a calm, friendly adult feline.

A cat of either sex can fit into a multi-cat household — as long as the cat has been spayed or neutered. An unspayed female may incite behavior problems when she comes in estrus. An unneutered male is virtually certain to fight, to wander off, or spray. Furthermore, intact cats add to the cat overpopulation problem by producing unwanted kittens. (See CATNIP, Vol.1,No.12, March 1994, “Beyond the Hearth: Helping the Homeless Cat,” pp. 4-6)

Prevent Territoriality

“The key to successfully introducing a cat to a multi-cat household is to prevent territorial aggression,” says Dr. Nicholas Dodman, director of the Behavior Clinic at Tufts University School of Veterinary Medicine. In most instances of territorial aggression, one cat — often the new arrival — becomes the aggressor and repeatedly attacks one or more of its feline housemates. (See CATNIP, Vol.2, May 1994, “Aggressions,” pp.4-6.)

Think about your new cat’s arrival from perspectives of your animals. Your resident cats are comfortable and familiar with their environment. They know when and where you will feed them, which windows have the best view, and where to find the litter box. Suddenly, a stranger drops into their midst. The newcomer doesn’t know anyone — human or feline — and hasn’t yet learned the house rules. Out of fear, the newcomer (or one of the resident cats) may snarl. The opposing cat snarls back. As the cats exchange snarls, the posturing may escalate into a cat fight. This is not the start of a beautiful relationship!


Once a cat becomes territorial, you will find it difficult to remedy the situation. But you can usually prevent territorial aggression if you plan carefully for your new cat’s arrival. Using the training principals of systematic desensitization and counter-conditioning, you can orchestrate the introduction of your new cat to its new home with a minimum of disruption. Your objective should be to habituate your cats to each other.

By introducing you newcomer and resident cats in a gradual (systematic) manner, you reduce their fear of each other (desensitization). By rewarding your cats with food or attention as you expose them to one another, you counter-condition their responses. Through this process, the cats learn to appreciate a pleasurable experience (food or attention) with the “thing” they fear (the other cat).

Two Rooms of Its Own

Before you bring you new cat home, select two rooms to use as a temporary quarters for the new arrival. If you live in a small apartment, you may want to use the bathroom as one of the “newcomer” rooms. Pick rooms with operable doors to prevent the newcomer and resident cats from intermingling. If you choose a room with a transparent glass door, tape cardboard over the glass to prevent the cats from seeing each other. Equip one of the newcomer rooms with a litter box and food and water dishes. Perhaps a comfortable bed for your new cat to sleep in.

Welcome Home

If you or other family members are not home on weekdays, try to schedule your new cat’s arrival for a weekend or a holiday so you can be with your cats during the critical first few days.

If possible, schedule other household pets away from the route you will travel with your new arrival. Carry the new cat (in a cat carrier or a box) to the first room it will occupy. Be sure the door is securely closed before you open the cat carrier. If the cat decides to leave the carrier at once, stay in the room with the cat for a few minutes. Wait for it to come to you. Fill the food and water dishes and show the cat where they are. Put the cat in the litter box.

If your new cat is not ready to leave its carrier or seems afraid of you, fill the food and water dishes and leave the room. The cat will begin to explore its new environment once it is alone.

Now is a good time to visit your other household pets. If you hid them away before you brought in your new cat, lead them out of confinement. They will smell the strange cat on you and know something is up, so you may want to reassure them that all is well. Try to play with and (perhaps) offer a few food treats to your dear old companions. Be sure to give your long-time feline residents plenty of attention. Before the day is over, they will discover the closed door and figure out that there is a strange animal behind it.

Frequently visit the new cat’s room. Don’t be surprised if your new companion retreats to a closet or under a bed when you enter. If the cat hides, stay in the room for a while and speak to it in a calm, reassuring voice. Try to entice it out of hiding by tossing food treats toward its hiding place. If the cat comes to you, give it as much attention as it wants — pet it, play with it, let it climb on your lap. But don’t force the cat to be with you if it isn’t ready.

Change Rooms

On the next day, clear all resident cats out of the second room you have chosen as introductory living quarters for the new cat. Move the new cat, its dishes, and its litter box to the second room, closing the door when you leave.

Leave the door of the first room open so your other cats can explore the room. They will smell the scent of their new housemate and rub against objects in the room to leave their own scent. This scent exchange is an important part of the desensitization process. Alternating rooms each day also helps to prevent territorial behavior.

Counter conditioning

Feed the new cat and resident cats on opposite sides of the closed door. The cats will begin to associate something they need and desire (food) with the smells and sounds of the stranger(s) on the other side of the door. If your resident cats enjoy playing, recruit another family member to play with them while you play with the new cat (or vice versa) on opposite sides of the closed door.

Increase the Exposure
Thus far, the cats have become accustomed to each other’s smells and sounds. As the cats on either side of the closed door begin to relax, let them use their primary sense — sight — to check each other out. Cats may need weeks of controlled separation — or only a few days — before they are ready to actually see each other.

When you think the time is right, open the door a crack. Securely wedge or hook the door so the cats can peek through the crack but can’t fit through the opening. Settle in a location where you can observe the doorway without being in the cats’ way. Don’t be alarmed if your cats snarl or hiss when they first see each other through the crack, but don’t let them become extremely hostile or frightened. Close the door again if you think the situation is getting out of hand. Wait until all of the cats have calmed down before you try the exercise again.

In the days that follow, continue to crack the door and watch your cats’ behavior. As the animals’ curiosity gradually overcomes their initial fear, increase the frequency and duration of “cracked door” time. Meanwhile, continue to alternate rooms and continue to feed and play with the cats on opposite sides of the door.

Together at Last

When you think the cats are ready to mingle, open the door and allow them to make their own introductions while you observe from a distance. If the cats become fearful or hostile, return the newcomer to its room and close the door. As you did with the cracked door, gradually increase the frequency and duration of “open door” time. Soon, the newcomer should be able to leave its room without incident.

If the cats remain unwilling to accept each other, try a different tactic. Wait until you know the cats are hungry; then put them in cages or cat carriers with wire-mesh doors. Place the cages on opposite sides of the same room with the cage doors facing each other, then feed the cats in the closed cages. Inch the cages closer together with each meal.

When the cats seem to be growing tolerant of each other, begin feeding one cat outside of its cage near the closed cage of the other cat(s). As an alternative to cages, you could recruit friends or family members to restrain the cats with harnesses and leashes as you feed them. Eventually, the cats should become habituated to each other and willing to eat peaceably together without restraint.

Only you can judge how to manage the pace of the introduction process. Some cats may accept their new living arrangement within hours or days. Others may need weeks or even months of gradual habituation. “This is a process of a few steps forward and one step back,” says Dr. Dodman. “Whenever you run into a problem, back up to a previous stage of the process and then carefully, inexorably move forward again,” he advises.

The time you spend gradually habituating your cats will prove to be time well spent. Your care and attention will establish the foundation for years of harmonious feline companionship.