What does it mean when a hamster shakes?

It means the hamster is very scared or surprised. If this happens all you have to do is give your hamster some personal space and come back later. To avoid this, never wake your hamster up when it's sleeping, never bother it when it's grooming itself, never take it by surprise, and make sure that it's not in direct sunlight or near an open window. Make sure to give it lot's of love!