Sudden angry cat

Question
We have two indoor cats (neutered ladies 2yo) that enjoy the screen porch on
sunny days. A neighborhood tom was outside and both gals were hissing and
running around at him. One disappeared into the house and is now hidden
under the bed for a day with no stop growls, even for her sister. In fact she
attacks the other if she comes close. Should we just wait her out until she
comes out to eat or use her litter box?

Answer
Michael,

There is a behavior called Redirected Aggression. That happens when a cat sees a strange cat outside and  becomes territorial, but can't get to the strange cat to defend his territory. The cat then turns on the closest animal member of the family and fights with them as if they were the other cat. They have been known to attack other family cats, even though they may have lived and gotten along together (as yours is doing), the family dog, and even their owners (though that is rare). They are not attacking each other in their minds...they are attacking the strange cat. It is also common that they can begin 'spraying' and defecating outside the litterbox due to the stress of the cat outside.

First thing you need to do is keep your cats from seeing the tomcat (out of sight, out of mind). If it is allowed to go on the cats may develop a permanent personality change.

If you can, keep the cats away from each other for awhile unless you are feeding them yummy cat treats TOGETHER. That is so they will associate something pleasant (cat treats) with each other and not unpleasant (the strange cat).

There is a very popular cat calming spray and plug-in you can use called Feliway (or Comfort Zone with Feliway). It is available at pet stores, vet's offices (they use it too), or on-line. It copies relaxing pheromones that cats produce from rubbing their faces on things.

There is also a calming product that you can add to the cat's food or water that reduces anxiety called Bach's Rescue Remedy. It is available on-line and in health food stores. Here is a link about it: (copy and paste, or type the whole links into your address bar)
http://www.bachflower.com/Pets.htm

If the cats are still being very stressed the vet can put them on "kitty Prozac" for a short term (usually 2 weeks) until they calm down. You may want to speak to the vet about it.

I am including links to 2 good articles on Redirected Aggression that may be helpful to you: (copy and paste, or type, the whole links into your address bar.

http://www.sniksnak.com/cathealth/aggression3.html

http://www.littlebigcat.com/index.php?action=library&act=show&item=redirectedagr...

I hope this helps.

Tabbi