Oh, one other thing. When I used to have gerbils a LONG time ago, I had these cool plastic tube sets. I think they could have been used as caged and they attatched to each other, but I used them separate from the cages like a getaway for them. I've seen cages with the tubes and all the fun stuff but I haven't seen ones that you can build on like the ones I used to have. You could buy more and more accessories and it was fun for the gerbils and for me to watch them. Anyone know where I can get something like that? I wonder if I still have my old ones.