Cats’ tails can be very useful indicators of their moods. Here are some examples: --

1. A cat who runs towards its owner with an erect tail, sometimes with the tip flicked over is displaying a happy greeting.
2. A cat whose tail ticks gently at the tip is usually signifying pleasure or anticipation
3. A tail twitching more actively from side to side often means an irritated, thwarted or frustrated cat…such as when a cat wants to go outside but it’s raining!
4. A cat whose tail is thrashing violently from side to side is one who is really furious---- and it is probably best to steer clear of.
5. A cat with a fluffed up tail is usually feeling highly threatened; particularly by another cat; or is alarmed by something.