Tail movements can be the easiest cat behavior to interpret
, or the easiest depending on the situation. When a cat wags their tail with short movements, it can indicate interest, happiness, or be interpreted in any number of different ways. When they move their tail in wide, side-to-side, concentric movements it usually indicate they're getting reading to fight, defend themselves, or they will also show this kind of tail movement before pouncing on their prey (or a toy).