Introducing Your New Cat
To Your Other Cat(s)

Cats who live in the same house may never become the best of friends, but usually learn to at least tolerate each other with a minimum of conflict. You will need to take some time - days to months, depending on the cats - to introduce your cat to other family pets in order to prevent fearful and aggressive problems from developing.  Neutering/spaying of all cats to be introduced is essential, ideally at least a month before the introduction, so the hormones levels have time to subside.  Generally it is said that the easiest introduction is when the new cat is younger, smaller, and of the opposite sex, but it depends on the personalities and experiences of the cats involved.

1. Confine the new cat to one medium sized room with its litterbox, food, water, and a bed. Feed the present cats and the newcomer near either side of the door to this room. Don't put the food so close to the door that the cats are too upset by each other to eat. This will help to start things out on the right foot by associating something enjoyable (eating!) with each other's presence. Gradually move the dishes closer to the door until the cats can eat calmly directly on either side.

If you have adopted the new cat from an environment (like a shelter) where it was exposed to sicknesses it could be incubating, follow the recommendations of your vet for the duration of this isolation.  Typically, for the most common sickness (Upper Respiratory Infection), it will need to be 7 to 10 days.  That may seem like a long time, but in addition to keeping your resident cat healthy, the new cat will have a chance to get adjusted to his/her environment's sounds and smells. The chances that the first face to face introduction with your resident cat(s) will go well are improved - which is very important!

2  Next, use two doorstops to prop open the door just enough to allow the cats to see each other but not get out (an inch), and repeat the whole process.

3. Switch sleeping blankets between the new cat and resident cats so they have a chance to become accustomed to each other's scent. Also put the scented blankets underneath the food dishes.

4. As long as the new cat is using its box and eating regularly while confined, after the incubation/isolation period is over, you can let it have free time in the house while confining the other cats. This switch provides another way for the cats to have experience with each other's scent without a face to face meeting. It also allows the newcomer to become familiar with its new surroundings without being frightened by other animals.

5.  The final moment - the first full meeting!  Just open the isolation door and calmly observe.  Hissing, posturing, growling are normal, but should be minimal if you have taken the time to follow the steps above as suggested.  It may be that the first meeting is only a few minutes if the hissing/growling starts to escalate.

You want to avoid any interactions between the cats which result in either fearful or aggressive behavior. If these responses are allowed to become a habit, they can be difficult to change. It's better to introduce the animals to each other gradually (five minutes more each day) so that neither cat becomes afraid or aggressive. You can expect mild forms of these behaviors, but don't give them the opportunity to intensify. If either cat becomes fearful or aggressive, separate them, and you may have to take a step or two back (back to feeding on either side of propped open door for example) and slowly move forward when they've calmed back down.

Cats can make lots of noise, pull each other's hair, and roll around quite dramatically without either cat being injured. If small spats do occur between the cats, you should not attempt to intervene directly to separate the cats. Instead, use a spray bottle to squirt water on the cats in order to separate them (or if that doesn't do it, trying to cover and wrap one up in a blanket to get them separated). Give them both a chance to calm down before re-introducing them to each other - like a day or more. Hopefully, none of this will be necessary, but if so, be confident that while cats can take weeks to months to get adjusted, most cats can learn to get along, if not become the best of friends.

Tips for after the first introduction

• keep the second litterbox in the isolation room even after the cats are out together, as long as they continue to use only their own litterbox
• clean all the boxes more frequently
• make sure that none of the cats is being "ambushed" by another while trying to use the box
• keep the resident cat's schedule as close as possible to what it was before the newcomers appearance.

If you find this program helpful, please make a donation to the Pasadena Humane Society & SPCA. You can donate online or mail a check made out to PHS to:

BEST Training
Pasadena Humane Society & SPCA
361 S. Raymond Ave.
Pasadena, CA 91105