When my neighbors cat came over

My neighbors (female) cat was in the backyard and my cat (female) was looking outside. (My cat is a indoor cat.) And when my cat saw my neighbors cat her tail was tumping wildly. I don't know if she was scared, mad, or want to go play with her. Does anyone know?

 

tail twitching I believe is mad

 

http://www.kittyangels.org/language.html

 

Booger's tail twitches in anticipation (like when I pick up the laser light, she begins chattering her teeth and twitching her tail right away) and her tail twitches and thumps when she see's kitties outside her windows. I think she's more exicted than upset. She's watched me pet the outside kitties and had no problem curling up with me when I come in right after. I really think it's more curiosity and excitement myself. But I also think that all cats (like people) are different in how they react.

 

I think it indicates that a cat is highly aroused, not neccessary excited or angry. I've seen my cats do this during stressful events (such as nail trimming) but also during play.

 

Most liekly not a good sing. That cat is invading your cats territory. My cat is the same way if he sees a cat outside. His tail starts going and he gets mad! Sometimes he will even growle.