Cats twitch their ears when they are anxious or nervous. If their nervousness or anxiety is not alleviated, the cat begins to press the ears farther back on the head, indicating increased fear, annoyance and anger. When the ears are turned back, the cat is ready to attack and should be avoided. If a cat continually twitches its ears, it could have an ear infection or ear mites.
A cat's ears are extremely flexible, with over 20 muscles controlling them. Each ear can move independently of the other, allowing the cat to be very aware of sounds in its environment. Besides being excellent sound receptors, the ears of a cat are also excellent indicators of the cat's mood. When the ears face forward and straight up, the cat is alert and happy. The ears slowly flatten and move toward the back of the head when the cat becomes nervous and angry, with a twitch being an early warning sign that a burst of anger is imminent.
Besides the ears, other parts of the cat's body can give signals identifying the cat's mood. The tail and the eyes should be observed to predict how receptive a cat is to human attention. Swishing tails are an indication that the cat is curious and playful. However, a tail that moves very rapidly back and forth could be a sign of nervousness or aggression. Wide open eyes indicate that it is time for play, while narrowed eyes are a sign that the cat is best left alone.