Okay, I've got two boys, both about 2 1/2 months old. I've read people on here talking about their piggies being in puberty. How do you know? Peanut is acting weird. He sometimes gets in these moods where the stalks around the cage real slow - almost like a cat - and tries to sneak up on Butter. Butter just goes in the pigloo and won't let Peanut in until he starts acting normal. And the other thing he does is he makes this weird little cooing/wheeking noise and tries to mount Butter. But they are both boys!! I have checked their sex, and there is no doubt they are boys. Anyway, Butter won't have any of it and either goes in the pigloo or sits on top of it until Peanut starts being normal again. It's not really worrying me - it's actually kinda funny to watch. Butter is the same age buts has this "little old man" attitude about everything.