Almost 10 percent of a cat’s bones are in its tail, and the tail is used to maintain the animal’s balance. A cat’s tail plays a vital part in its “righting reflex” that allows it to land on its feet after falling from a height. Cats often survive a long fall based on their agility and balance, which they develop as kittens. When falling, the fluid in the inner ear shifts and the cat rotates its head until it equalizes and the fluid is level. The body automatically shifts to follow the head, and the cat lands on its feet. A cat also uses its tail to communicate. A cat’s tail held high means that it is happy. A twitching tail is a warning sign that it may be angry or on guard, and a tail tucked in close to the body is a sign of insecurity or tearfulness.