How thin of a crack can a hamster get through?

As Quora User stated in his answer, anything a hamster's head can fit through, they can get their body through. What does this mean to you? It means a smaller species like Roborovski hamsters can fit through incredibly small spaces. read more

I once read that if you can fit a pencil through the hole, a Robo can get through it. Same for mice, by the way. The larger hamsters need a little more space, certainly, but not as much as you might think. read more

Our hamster was able to get through a crack behind a bookshelf and a wall that was barely big enough for my thumb. And he was a pretty fat hamster, a regular-sized one, not one of those mini-hamsters. read more