What Does It Mean When A Cat's Tail Vibrates? What Does it Mean When a Cat Wags Their Tail? Guide to Cat Tail Language Kinship 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 is my cat's tail vibrating: Understanding the Behavior Desk Cat Nest Why Do Cats Vibrate Their Tails? Reading Your Cat's Body Language Kinship