Your hamster will try to squeeze out of his cage. When he does, he will either find it impossible, he will escape, or he will get stuck. The only option should be that it’s impossible. Therefore, the bars of a cage holding a Syrian hamster should never be more than half an inch apart. If you have a dwarf hamster, the maximum space between the bars should be half of that, which might be very hard to find. If you have a dwarf hamster, the best option is to use a different type of cage.