rat aggression

Question
I have two male rats (litter mates) who will be seven weeks old as of tomorrow.  In the past week they have begun scrapping, and one of them is being particularly aggressive.  He'll attack without any provocation, and will pin the other one down until he squeaks.  Even when he lets him go, it doesn't seem to be uncommon for him to go for him again a few moments later.

Neither of them have drawn blood, and they can still happily sleep with and groom each other, but I am still a little concerned by this behaviour.  Especially since most sites I've found seem to indicate this isn't common until about six months.

Is there anything I can do to discourage this aggression?

Answer
Its not really aggression.....its play fighting and the rat is showing a bit of alpha male in him, but this is common for baby rats of both genders to scrap, chase, box and push and shove, and its all a part of their social skills.  True aggression is when your rat is on his hind legs, fur puffed out,sometimes even grinding their teeth as if bruxing but this is of course NOT the time to brux.  They may circle each other and start to shove each other before the actual physical contact begins. This may or may not occur as they hit puberty around 6 to 8 months old and it may never happen, either.  I have had more males than females as pets and only have had a few serious issues with aggression in rats going through puberty.  Never as babies.  Its very unusual for aggression in baby males other than a bit of a more serious sparring match.  No blood, no foul.  You may even find a nip here or there and a scab or two, but allow the other rat to defend. He may or he may not, but either way, this is very common.  Keep food down at all times so the alpha doesnt eat it all.  If they are fed on a schedule this will tempt the alpha to hoard which can result in the other rat not getting enough food to eat.