What is she trying to tell me? Vibrating tail??? : r CATHELP Ask A Vet: Why Does My Cat Twitch His Tail? Why Do Cats Vibrate Their Tails? Reading Your Cat's Body Language Kinship Cat Tail Language: What Your Cat's Tail Really Means You asked and we picked one question to answer this week: "Why does my cat shake her tail like a rattlesnake?", We've got the answer below from behavior professional Kenzie Korpela, IAABC SBA, CFVA.