MMMM. What size cage would you recommend then? He's in a 16x16x24 'bilevel' - there's a plant ledge that kind of divides it in half. What if I had a new one built that was twice the length (32lx16wx24h) - do you think that would be good enough? I wonder if they'd need separate food dishes?

But then again, I'm a bit of a chicken to risk it. I'll probably just go with a second cage. When you group females together, do they 'socialize' at all or stay to themselves?

I forgot about the Millipede!