Cat has Snapped and turned on Other Cat

We have a black cat we got from a shelter about 2 years ago. She has always been skittish and afraid of quick movements, and very shy of new people. We got an Ocicat at the same time, and they have always been very good friends.

The black cat and the ocicat enjoy looking outside of a window that is opened and a screen keeps them from getting outside. They are both strictly indoor cats.

Just recently, the black cat has snapped and now HATES the ocicat. She hisses at him, and at one point (when we discovered this) she really flipped out and peed all over a room when he tried to approach her, and she made horrible growling noises.

We have been keeping them seperate ever since. This started yesterday (5/26). Everytime the black cat sees him she hisses and he hisses back. The black cat still really likes us and likes being petted, etc.

We think what happened is a neighborhood cat wandered near their looking window and triggered something in the black cat that caused a panic attack, and made her turn on the Ocicat for no real reason. In the past she has strangely cackled when she sees birds outside the window but has never been like this before.

Today we will be trying some pheremones and catnip to see if that can get her to snap back. These cats were the best of friends before and the Ocicat is very confused on why she is acting like this to him and it makes him scared.

Anyone have any tips or ideas, if they have had this happen before?

Thanks so much.

I would take things slow with the black cat. If you can, I would keep him in a separate room for awhile and slowly introduce them all over again. The cat nip idea seems pretty good because that would calm them down. There are some ways to introduce the 2 cats that are on this website that seem pretty helpful. If anything else seems weird about the cat, I would take it to the vet.

Take the ocicat to your vet- it is possible the cat is ill and your black cat is trying to tell this.

Put some pure vanilla on both their chins and base of their tails (on their backs). If they smell alike, it will help a lot.

Sounds similiar to what happened to my cats. Broccoli and Garogmel have lived together for 2 years and have been best of friends, until one day Broccoli snapped and couldn't tolerate seeing, much less being in the same room as Gargomel. He would growl and hiss and Gargomel. Which oddly, make Gargomel start peeing at random spots in the house. He had never done this before. After a trip to the vet ruled out any health problems, I started to pay attention to everything closely, and realized, that a neighborhood cat had gotten accustomed to sleeping outside our window at nights. Everytime we saw the neighborhood cat, we would make sure, we chased him away (I know this sound sad). But it worked. It took some time for our cats to become friends again. We had to keep them seperated but we would put their food bowls on opposite sides of the doors so they could smell each other when they ate. It took about 6 days of this for them to be friends again, but it was worth it. Now they are best friends, playing, cuddling, and grooming each other again.

Maybe your cats saw or smelled another cat outside. I would suggest taking your cat to the vet to rule out any health problems. Sometimes they become aggresive because they are sick. Once you get a clean bill of health, just give it time. You can also try feliway. I've seen alot of other members on the board suggest it.