Why Do Cats Vibrate Their Tail? This Is What They Might Be Signalling With It We Love Catz what does it mean when my cats tail and back muscles quiver like this? How to Read Your Cat's Tail Language and Meaning PetMD A cat's tail is a powerful form of communication that reveals its emotions and intentions. When the tail is erect and twitching, the cat is usually excited or happy, while a straight up Why Do Cats Vibrate Their Tails? Reading Your Cat's Body Language Kinship