Cat Tail Language: Common Positions & What They Mean Why Do Cats Wag Their Tails? We Asked a Cat Behavior Expert Why Do Cats Shake or Vibrate Their Tails? Vet Verified Reasons Explained Catster Cat Tail Language: What Your Cat's Tail Really Means Rattlesnake Tail is one of the signs of the *most* excited happy cats. It can be confused with the behavior of spraying, but in a fixed cat, its actually just an extremely excited cat!!!!! #happycat