Okay, I've read all sorts of stuff on how to tell one from the other. Most of the articles say that if there is no noise, it's play. In this case, Cricket is making noises like she is being hurt by Austin. He is making no noise whatever. So I break it up and separate them. I do not know if it's play or real fighting. Austin will often sniff her and then throw his front leg over her and bite. I stop him from doing that when I see it. I know he's trying to be dominant. But I'm not sure how to put a stop to it and get them to just get along. Most of the time they are fine, although not good buddies or anything, and he gets upset if she is anywhere he doesn't think she should be (like a cat tree, our new ottoman, our bed). He can be very sweet kitty, but not liking that side of him.