Thank you soo much for telling me that....In my many years of taking care of and raising ratties, I've never NEVER had a rat be aggressive... I used to always preach that rats were the LEAST aggressive rodents I've ever encountered (when I was a bit younger). The reason I was so worried about the random aggression is....back when I was around 12, I went to the pet store with my father (he was a "DIE-HARD" rat lover...he raised me like that) and at the store we were planning to pick out a new baby for one at home that was in need of company...What happened at that pet shop still haunts my father to this day...He had me put my hand in the cage to see which baby was the most friendly. One was obviously more friendly so I picked her up out of the tank and said "I think this one is perfect". My dad, who was the epitome of a true life-long rat lover, asked to see her. I handed him the sweet baby...and just as I handed her to him, she flew of his hand (out of fear from all the handling [from strangers]) and fell on the petshop floor. After she hit the floor, she froze, paralyzed for about 1 or 2 minutes... She was NOT okay...It caused brain damage..from that moment on, she acted strange and nervious. We went ahead and bought her because she was literally in shock from the fall so we couldn't just put her back [and wouldn't have even if we could]. She never acted normal (loving, trusting) again....and my dad's heart was broken. My dad is the quiet, wise kinda man...and I know never to bring that up because he looks incredable sad everytime he thinks about it. Anyways, I was just worried that "what if the people who had the babies before we bought them had dropped her, or what if one of their kids grabbed her to hard...because we do know that they had 2 or 3 young (ages 1 to 9) children who had access to the baby rats. I will definately try to be extra careful with the (more aggressive baby)...and I'm so happy you wrote me back because my inclination was to find her a different home, or at the least keep her separated from her siblings. Oh, and don't worry..In the next couple of days we're going to separate the [5 week old] brothers and sisters so theirs no horrible breeding nightmares. Anyways, THANK YOU ALL!!!