When your cats are chasing each other, hissing, and pouncing, you may find yourself wondering, are my cats playing or fighting. Body language can tell you a lot. Both playing and fighting can involve jumping on each other, chasing, and even a little hissing. If your cats' bodies are relaxed or their ears are pointed forward, they're likely just playing. Cats that are play fighting tend to take turns, letting one cat be at the bottom of the wrestling huddle and then the other. They might even take brief breaks to rest. If your cats flatten their ears, hold their ears back, or puff up their fur or tails, this is a sign that they're fighting, not playing. Defensive, puffy postures and leaning away from each other while hissing with bared teeth are signs that your cats feel threatened and aren't having fun. Chasing a tired cat until it hides could also be a bad sign. Inflicting injury is another indication things have gone too far. Watching how your cats act around each other when they're not playing can help you see more clearly how serious the situation is. If they groom each other, cuddle with each other, or generally live peacefully together, they're likely just playing.