One thing that I think gets forgotten when housing our charges is that they naturally live in a range of temperatures. And for most there is an overlap of temperature range. It is one of the many considerations, along with humidity level (again a range) when considering whether or not to set up an enclosure with a mixed population.

Most of my tanks (be them for fish or the repts) are in my fish room, in none of them do I use heaters. Although my house temp runs around 72 during the day and I drop it to 69 overnight, the fish room generally hoovers around 74-76 during the day, dropping to 70 overnight. The difference in temperature in that room is due to the lighting, humidity, and by sunlight coming through a particular window heating that small room. Those of my creatures that perfer a higher temperature are placed on the higher shelves (heat rises), and those requireing lower temperatures and placed on lower shelves. There can be as much as a 5 degree (f) difference between a top shelf and the lowest shelf.

I learned years ago to use the "micro-climates" that are throughout any given house (or apartment), such as corners that tend to be cooler that the room itself because of less air flow. It is surprising just how much fluctuation or variation of temperature there is within a house or even within a room.

We also create "micro-climates" within an enclosure with the placing of under tank heaters, lighting, heat lamps, screen covers, or glass covers,even water features change the immediate area around it. And yes... the larger the enclosure the more "mirco-climates" that can be created thus allowing the creature to decide for itself what its needs might be at any particular moment.

I kept anoles with fire belly toads together for several years. Both have similar housing requirements, but live in different niches of that environment, the toads using a horizontal plane, whereas the anoles occupy the vertical. Both m. klappenbacki and n. viridenscens occupy the same niche in a similar environment, both living on the horizontal plane, with the m. klappenbacki being more agressive feeders, who would out compete the n. viridenscens.

Only with a great deal of research and understanding of a creatures individual needs can informed and intelligent decisions be made as to housing a species let alone mixed populations. The animal did not make the decision to live with us, we made that chose, therefore we are obligated to provide for the needs of that animal.