We've had 2 cats at the same time before but right now we just have one. When we had 2, one of them was a mature tomcat and the other one was a kitten when we got him. The older cat would get aggravated at the kitten but they got along pretty good overall. You could definitely tell which cat was the alpha even after the kitten grew up. The older cat would smack the younger one when he would get a little too rowdy but he didn't do it too often as he knew he ruled lol!