So about 2 weeks ago, I adopted 2 cats: a 1.5 year old male Tabby named Axel and a 3 month old female Tortie Kitten name Brie. At the shelters recommendation, I introduced them together when I got home and they appeared to get along just fine when confined to a bedroom together (no hissing or aggressive behavior). Over the past few days however, they seem to be getting more rough with each other. They'll chase each other around, the little one will bat at the older ones tail, or walk up and bop him in the face. Usually it seems like she instigates but sometimes he'll pounce or charge at her too. Some of their "roughhousing" leads to him biting at her, going for the neck, legs and belly which causes her to squeak-meow (he hasnt drawn blood). At that point I usually yell and clap to break them up and if one keeps charging at the other after that (usually her when he tries to run away), they get a time out in the bathroom. When they are separated, they play with each others' paws under the door (again silently). They seem to be more open to fighting/playing/whatever with one another the last few days. I've still heard no hissing at one another and they can also play well together and he will groom her. As this is my first time with 2 cats (and a kitten) I'm concerned with how rough their play can become. He never seems to be fazed but she sometime gets a puffed tail after. Should I separate them and try to do a re-introduction? Or is it just a difference in size and strength that's making the play seem more violent?