A Bug's Life

I've only had rescue hamsters recently, and they seem so delighted to be living in a nice new house that they obligingly come and play a lot. Perhaps I should show Heidi hamster some serious neglect for a couple of months, so she appreciates her humans more ;-) We know she's still in there, because food disappears, and when we clean her tank we discover damp hamster pawmarks in the most outrageous places on the glass. How does she get up there? Perhaps we need a hamstercam.