Oh, but you know what, for the first day I *do* put a towel in there because their little feet are not ready for the rough surface of the straw. Even paper towels with a rough texture should work fine. If you have any rubber shelf liner, it's perfect for this purpose and you can throw it away when you're done if you want (though I rinse it off and re-use it). They don't poop much the first couple days anyway, so it's really not that gross.