Now ANOTHER way to create a burrow thereby proving cool zones - without cutting holes or major mods and creating a great landscape is using excavator clay. You moisten it up and setup you cage how you want it, like dirt but it will harden and have a hard sand like texture. You can run driftwood wood out of it etc. To create burrows use balloons and they will make caverns once popped.. those caverns will be colder than the ambient air. If you wet this stuff enough it will se-solidify it unless you use a product to harden it.