With different terrarium sizes: Maybe we can clip two or more terrariums together and leave one empty? That way it might look bigger at least. Don'z know if it's actually possible, but if it is, that could be a workaround.
I guess you could! You can put multiple together in a hub and use piece-by-piece building to set it up nicely
Just want to chime in here and thank Bo for the excellent clarification. No beating around the bush, just clearly stating what we can expect, that's my fetish. The decision to not make them as resource intensive as the other animals seems entirely reasonable to me. The obvious advantage of this is that it allows for a much greater variety of terrarium animals (including birds, I would figure), since the devs don't need to develop the full spectrum of animations and AI for each species. Having said that, animals being stuck in a single animation loop got boring very fast in ZTUAC, so I'm very happy to hear that at least they can be found in different places some of the time!
Thanks, appreciate the kind words and I'm sure the devs who are reading this do as well!