Cat Tail Language: Common Positions & What They Mean Why Do Cats Vibrate Their Tails? Reading Your Cat's Body Language Kinship What is she trying to tell me? Vibrating tail??? : r CATHELP 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.