My own cat, whom I thought could use a friend, now acts like I ruined her life with the presence of another cat. We agree with our cat--our lives are also ruined due to constant sleep deprivation as the two cats hiss and growl at each other all night long.
I have one year to try to get the cats to become friends and try to keep the older cat alive.
Tips on introducing cats to one another (from about.com):
- Set up a comfortable "safe room" for New Cat. Put her food, water, litter box (not near the food), scratching post, toys, and bed or other sleeping mat there.
- Expect a great deal of "hissy-spitty" behavior through the closed door from both cats. This is natural and normal; they are just starting to explore their "pecking order."
- Scent is very important for cats. Let each of them smell the other indirectly, by rubbing a towel on one and letting the other smell it. They will soon accept the scent as a normal part of the house.
- Once or twice, switch roles. Put New Cat in the normal living quarters, and let your resident cat sniff out the new cat's Safe Room.
- After a day or so, let the two cats sniff each other through a baby-gate or through a barely-opened door. Gauge the rate at which they seem to be acclimating to each other.
- When you think they're ready, let them mingle under your supervision. Ignore hissing and growling, but you may have to intervene if a physical battle breaks out. Again, take this step slowly, depending on how quickly they get along. If they do seem to tolerate each other, even begrudgingly, praise both of them profusely.
- Make their first activities together enjoyable ones so they will learn to associate pleasure with the presence of the other cat. Feeding (with their own separate dishes), playing, and petting. Keep up with the praise.
- If things start going badly, separate them again, and then start where you left off. If one cat seems to consistently be the aggressor, give her some "time out," then try again a little bit later.
I think that the most important thing is time and patience. I am still in the stage of supervised mingling--I feel like such a cat mommy.