Hi, I'm Julia, I have 4 rats, all from the same breeder, in a very large Ferret Nation style cage. My breeder is quite reputable and well known in my area, she's great and breeds amazing healthy rats with great temperaments. However, for about a month now, one of my rats Mick has been demonstrating some very unwanted behaviors here and there. He's a big dumbo rat, and the biggest in my mischief by a long shot. I would say 90% of the time he's extremely friendly and he's very bonded to me. That other 10% though he can be quite difficult. He plays very rough with his brothers, to the point where they're squeaking way more often than when they play with another rat besides him, I sometimes have to break it up bc I'm worried it'll turn into a small dispute. Let me preface by saying I've had all four rats for 4 months now, they're all coming up on 6 months old fairly soon (which I know can cause some hormonal issues). Another issue is that twice over the course of the last month he has bit me and drawn blood. Both times were very unprecedented and nothing about his body language told me he was going to do it. The first time I was cleaning their cage and they were all out and about in the room I keep their cage in, playing and exploring. And he love to hop on my lap and hop down and pull at the trash bag all playful, he was scurrying around and tackling my hand and I decided to rough house with him like I do my other rats, and he bit me hard. I brush it off thinking he may have gotten spooked or bitten me because I was playing too rough for his liking. But then over the course of the month occasionally when i was picking him up he would bite me. It wasnt nearly as hard as the first time and didnt hurt at all. I took the light bites as him telling me I was in his space and that he wasn't happy with being picked up. Every time he did it though I would say "no" and pick him up anyway and hold him close to my chest, so he would understand that biting me was not going to make me not pick him up. I didnt want him getting into the habit of biting when he want in the mood to be picked up. Fast forward to today, I was just letting them out for their daily play time and everyone was having a fun day and running around playing. He was jumping all over my lap, climbing my shirt, jumping into boxes, climbing his cage to get to the top, all normal stuff. I'd picked him p to set him on my lap 5 maybe 6 times and he was great. But then I went to pick him up again and completely unprovoked he bit me hard and drew blood. I immediately put him back in his cage bc playtime was done for him, and rounded up my other rats so I could clean the bite and stuff. And when I put his brothers back inside, he started picking a fight with one of his brothers which I split up bc I know it was completely unprovoked and he was the instigator. It's definitely aggressive biting and it's a behavior I'd like to get rid of. I am not quite sure what else I can do though, I've been trying to get him to understand that biting isnt a solution, and that it results in less or no playtime, but evidently it hasnt been enough. My breeder suggested I neuter him to get some of those territorial/aggressive tendencies that come with testosterone/hormone imbalances, but I'd like to know what other people have tried in similar instances. As I mentioned, he's most of the time a very sweet rat who loves to be around me and cuddle and climb on my lap, but this bipolarity isnt something I can just brush off, especially bc when it happens his body language never indicates he's scared or angry. I just wanna know if there's any good training tactics and solutions to help me get rid of that small part of him that's a little rough and mean. any suggestions would be great thanks!