How to Read Your Cat's Tail Language Cat tail language Petplan What is she trying to tell me? Vibrating tail??? : r CATHELP Serval Wikipedia Why Do Cats Shake Or Vibrate Their Tails? What Does it Mean? 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.