Agressive cat behavoir toward dog

Question
I have a nuetered 6 year old female cat, loving cuddly. She has a screened porch we spend time on and if a stray cat goes by the tail poofs! teeth snarl ! hands come out wacking!!! You cant go near her Recently she is exhibiting this behavoir with a small dog she has lived with for 4 years after seeing a cat in the yard. We bathed the dog to get rid of any other cat scent but she seems to want to stalk the dog. The dog is 11 years old and now a nervous wreck. HELP

Answer
Darlene,

This is common behavior with very territorial cats, though usually it occurs with male cats (is she a calico or tortie?) It is called Redirected Aggression. The cat gets frustrated that he/she can't get to the cat they see and they reflexitively turn on the nearest animal (or sometimes person) and fight with them. In your case it is your dog. But mentally it is not the dog she is fighting with. You need to put up sheeting, cardboard, or anything to where it is above eye level to the cat where she won't be able to see the other cat or cats. If it continues she may develop a permanent personality change. Keep the dog (and your hands) away from her when she exhibits that behavior until she settles down.

Here is a link to an article on redirected aggression. Copy and paste or type the whole link into your address bar:

http://www.animalbehaviorassociates.com/pdf/RMN_cats_fight_outdoor_cats.pdf

I hope this helps!
Tabbi