Random aggression

Question
Hi, I've had my rats for around 8 months. One is a proper "mummies boy" (Loki) apart from the odd  little mischievous nip he's as good as gold. My other rat who is slightly older however has random episodes of aggression. First we thought it was a dominate thing. He was going through a teenage hormone fueled thing and biting. He doesn't bite his cage mate just us. He doesn't only bite but he latches on and really goes for it. I started off thinking because I thought it was hormone related it was as though he was trying to "mate" with my arm and there was a pattern (we thought about getting his balls chopped, but didn't to see how things go) now there doesn't seem to be a pattern he is completely normal then just turn's into psycho rat. He bit me in the face this evening so he's become more bolder. We've trie to make a noise to tell him he's done wrong, put him in the back in the cage to cool off but nothing seems to work he goes back to being cute a fluffy until he decides to bite again! Please help. I've had 3 other sets of rats and never had this problem :( thanks in advance.

Answer
I'm so sorry I haven't replied to you sooner.  Your situation is a bit perplexing and I cannot say with certainty the cause of your boy's random aggression considering that he was sweet and tame prior to recently.  Rats become full grown around 6 months of age, so because your boy is 8 months old now, it makes me lean towards the idea that this is testosterone related.  Thus, neutering him would be something to seriously consider.  Because the aggressive acts are becoming worse, who's to say that he won't eventually turn on his cage mate, which could be tragic.  

Should you choose not to neuter, then the only thing left is to try to patiently work with him on relearning appropriate behavior.  

Aggression in pet rats Is an interesting subject.   I'm going to include this link to an article about aggression.  This website may give you some more ideas on how to handle the situation.
http://www.joinrats.com/ModifyBehavior/BitingRats/

Good luck with your boys and write back if you would to give me an update on how he's doing.  Please let me know if there's anything else I can help you with.