Are My Cats Play Fighting Or Real Fighting?

[Alex12]

I just recently moved in with my boyfriend and we each have a cat (both males). We've been slowly introducing them, feeding them on opposite sides of the door and letting them see each other through a baby gate for several weeks before finally letting them meet. They seemed pretty fine with each other when we were taking the baby steps, no growling hissing or ears back, but my cat does get his hair all puffed up when he sees the other cat so I was a bit worried. When they finally let them meet face to face my cat was super friendly (purring rubbing his face up against the other cat etc) although he still had puffy fur. We only let them meet for short amounts of time because my boyfriend's cat gets a bit overwhelmed by how friendly my cat is so we just have them socialize for a few minutes at a time before separating them again. Recently though, my cat has started to sometimes pounce on my boyfriend's cat after being friendly and rubing against him only seconds ago. He will even sometimes stalk up on him and pounce. I want to believe it's playful but with how puffy his fur gets it makes me worry a bit. I can't tell if they're playing or fighting. It also worries me that my boyfriends cat may be seeing it as agression even if it is play and it escaltes into a real fight but i dont know hecause it happens so fast. Although there's no growling or anything (we do brake it up pretty quick though because it scares us) there are often tufts of fur left around. Do cats really play so rough that they tear out fur? How can I tell if the kitties are playing or fighting? Should I break them up or let them rough it out? Or is it possibly a dominance thing because they are both males (both fixed)?

 

[abyeb]

This is what play fighting should look like:

 

[Alex12]

This is what play fighting should look like:

Thank you! I feel this does clear it up a bit I think my cat is trying to be playful! Thanks again