My new hamster looks like a Campbell dwarf, but she may be a hybrid. She is my first hamster, and she is from a pet store. The tank they kept her litter in simply said "dwarf hamsters". I'm just curious if there is a way to tell by looking at her.
The general rule is "If you can't prove they're a purebred campbell (or a purebred winter white) then you have to assume they're a hybrid"
As evel_lin said your ham will almost definetly be a hybrid