I'm not sure either. Both my boyz want to chase the cat - not all the time, but some everyday. Of course, the cat chases them sometimes too - mostly when they get up in the night to go out to potty. She waits in the dark and pounces them as they are trotting back to the bedroom
I get on to them when they chase her hard - and they will stop, but then they will turn around and chase her again, a few minutes later.
They don't actually fight or anything, but she will run and just and knock things off, trying to get away from them.
So, I'm no help, but would appreciate some help too, from any experts!