I have a very small baby dwarf hamster and it can not go through the bars, so They are close enough to eachother. So it can not climb over it. As long as the hamster has enough distractions inside the space in order to not get bored, it will not bite into the bars much. DEPENDING ON how much space you have in your room, I would suggest buying two of them to have a bigger area for the hamster. Or just do it like me: connect it to a big cardboard maze to increase the space and the hamster's interest considerably.