So my friend just bought her first two male rats, in July. I would say they were born about late may, early June. 1 of her rats Congac is biting a lot. Her mother put her hand in the cage and he charged her and bit her. My friend also got bit by him last night. Both times he drew blood. Hypno isn't biting, he's actually really good. I just told her it might be that he's going into puberty and what-not..and i`m hoping that's the reason, because he's getting worse.