Aggressive at day one. Will mature at around 6 months. Just make sure to keep enough space around them that they can get away from each other. Maybe three to a 18"x18"x36" cage at two to four months, depending on their size. Separate to their sizes. Lots of plants, branches, hides, etc... you could always try the dragon strand nursery cages. I was skeptic at first, but i mean common sense is common sense, right? I will not go extinct, because of unwillingness to adapt or change. The first month or two they should be ok, just carefully watch after that. Most of all my litters were 15-21, some even only had 9. So, not really sure on the big populations.