What does it mean when a cat's tail vibrates? what does it mean when my cats tail and back muscles quiver like this? Anyone else's cat do this? She vibrates her tail when she is happy to see me A Guide to What Your Cat is Communicating: A cat's tail is far more than just a balance toolit is a sophisticated emotional barometer that broadcasts their internal world. When your feline What is she trying to tell me? Vibrating tail??? : r CATHELP Why Does My CAT'S TAIL WAG When I PET THEM? Tail Wagging MEANINGS!