Welcome to Jurassic Habitat.

My thought is that a visit there would be more like a safari than a visit to the local zoo. A habitat can be similar in size to a small country, or using carbon nanotubes, maybe similar in size to a large country. It can even be a cylinder longer than it is wide, because all you need is another one counter-rotating.

End-to-end, not side-by-side. Heh heh.

I find it interesting that Jeff also came up with this idea. Good luck with it, Jeff. You are more likely to do something with it than I am, judging by my track record. And if I ever do manage, maybe I can plug your book in a Forward or something.