when we got paris(our adult) she was/is pretty hostile. now she hisses and yowls, but doesnt swipe unless bella gets too close. shes started to go up to bella and swipe, so now she gets a tap on the butt whenever she touches bella. with our kitten, we put him in a cage with a towel over the back (so he felt secure) and let the animals introduce themselves. then after they had lost interest, I let him out, and he yowled and hissed and carried on. they didnt pay attention to him, but now Bella plays with him and sleeps next to him all the time. If Bella gets too rough he jumps up somewhere high.