This post goes over how to introduce a new cat to your household. The rules are similar if you have to re-introduce cats that suddenly stopped getting along because of something stressful that happened between them. This can sometimes be caused by a trip to the veterinarians office, where one cat comes back smelling differently and the cat that was left at home suddenly starts hissing or attacking the supposed “newcomer”. It can also be caused by re-directed aggression. This is where cat ‘A’ sees something outside a window like another cat or something frightening happens like a box falls nearby. Cat ‘B’ is standing innocently by and is attacked by cat ‘A’ who re-directs his frustration and confusion towards his housemate.

It is important to note that if you are introducing cats new to each other, there are several possible outcomes. The cats may become best of friends, they may exist with mutual tolerance, they may actively avoid one another with occasional skirmishes, or one or both may be so intolerant of the other that fights are frequent. There are some cases in which the quality of life of one cat is being so negatively impacted by constant harassment from another cat, that finding one of the cats another home may have to be considered. Hopefully, appropriate introductions can help prevent this unfortunate outcome.

It is always better to error on the side of caution, and assume that the cats may require as much as several months before they can freely be in each other’s presence. Certainly many introductions are successfully accomplished much more quickly, but be careful not to rush things.

Keep the resident cat(s)’ routine as much the same as possible by keeping feeding, play, and sleeping times and locations the same as before the new cat arrived.

At first, the cats should only be allowed to smell and hear each other, not see or touch each other. This can be done by confining the new cat to a small section or one room of the house with all the necessities (litter box, food, water, toys, bed, etc.).   

Place towels with the scent of the other cat underneath each cat’s food dish, and on resting places. Rub the cat toys with the scent of the new cat. The goal is to have this scent be associated with “good things”.

After the new addition is comfortable in her room (anywhere from several hours to several days), confine the resident cat in this area and allow the new animal to explore the house, under supervision. This allows each cat to become more familiar with each other’s scent. Switch the two cats back and forth for short periods of time over several days or weeks.

Feed, or offer both cats treats close to the door to this room (one on each side). This helps each to associate “good things” with the other’s presence. Use “to die for” treats, such as small pieces of tuna, chicken or salmon

Try slipping one end of a toy underneath the door to encourage the cats to paw at it or each other in a playful way.

Repeat these procedures until there are no aggressive or fearful responses and both cats begin to show some curiosity about the cat who is on the other side of the door.

Next, wedge the door open, from both sides, about an inch, with doorstops. This allows the cats to peek at each other, paw if they want to, but not have complete access to each other for things to go wrong. Do not progress past this step until the cats can see each other without fearful or aggressive responses. Continue to use toys, food and petting as long as the cats aren’t threatening. Touching an agitated cat may result in a bite.

Next, wedge the door open a little farther, but not so much that the cats can get to one another. Repeat the previous step.

An ideal next step is to give the cats full view of one another behind a screen or glass door before being allowed together.

When the cats are first together, keep the session brief, and continue to offer enjoyable things-food, toys, petting.

If the cats are threatening or fearful when close to either side of the door to the confinement room, offer the tidbits at a greater distance from the door, where both cats can be calm.

Do not move the introduction along too quickly. The cats should be tolerating each other well at each step before progressing to the next. One bout of fighting may set the introduction back for months.

During initial time together, if any hissing or conflicts occur, try to distract the cats into another activity-dangle a toy, get the resident cat into the kitchen with the sound of food preparations, etc. If these reactions continue, back up a few steps in the introduction process. This is an important concept for successful introductions or re-introductions; remember if fearful or aggressive behavior starts at any step, back up to the previous step that the cats were comfortable and stay a longer time at that step before advancing.

Avoid having the cats together in a small space, such as a car, until they have become comfortable with each other.

Supervise interactions at home, and do not allow the cats to be alone together until they are consistently demonstrating friendly behaviors with each other for at least a week.

Punishment is not helpful with cat introductions as it is counter productive in creating the association of “good things” with each other’s presence. It’s important that no “bad” things happen when the other cat is present.

If a fight does occur, try a loud noise such as an air-horn or ultrasonic device, or a water gun to break it up before either cat is injured. You can also throw a towel, pillow or blanket between them. Don’t try to pull the cats apart physically, you may get bitten or injured and the cats may even become fearful of you. This should be used to interrupt the current interaction, not as a repeated procedure.

If interactions consistently result in fearful, threatening or aggressive behavior, please let us know, more help may be needed at this point. Sometimes anti-anxiety medications are useful at this point to help cats relax enough to learn how to get along.

There are a number of important considerations when it comes to meeting the behavioral needs of a multiple cat household that can help minimize stress and help cats live peaceably together. The environment needs to be structured to decrease competition among the cats. No cat should have to face harassment and threats from another cat while attempting to meet his basic physical needs.

There should be multiple locations, or stations, for all the important things in life. Multiple feeding stations should be provided, so that the cats don’t have to jockey for position at one food bowl. Lining up several food bowls right next to each other isn’t sufficient for many cats. Place food and water bowls at several different spatial locations, depending on the number of cats and the degree of conflict between them. Food and water stations may need to be in different rooms or on different floors of the house.

Similarly, multiple litter boxes should be provided, in numbers at least equal to the number of cats, perhaps even a one or two more. These boxes should be in different rooms, and even different floors in a multi-level house.

Multiple objects for scratching are also important. Each cat may have individual preferences as to the location and texture of the object she likes to scratch, and these factors should also be taken into consideration. Scratching objects need to be easily accessible, and in areas where cats prefer to scratch. Locating one in the corner of the basement is probably not going to be helpful.

It is important to provide multiple cat perches, which allow the cats to use the vertical space to their advantage. Multiple resting places at different heights in various locations should be provided, in numbers relevant to the number of cats in the household.

Cats also need hiding places. Some are provided naturally, such as under the bed, but some rooms may lack them. Putting an upside down cardboard box with one side cut away behind the couch, a small decorative cat screen across the corner of a room, are examples of ways to create hiding places in rooms which have few, or none.