1. Campbell's Dwarf Hamster: The most common type, known for its distinctive white stripe running down its back.
2. Winter White Dwarf Hamster: Similar to Campbell's, but its coat changes color in the winter (turning white).
3. Roborovski Dwarf Hamster: The smallest hamster species, known for its speed and lively personality.
4. Chinese Dwarf Hamster: The only hamster species that doesn't hibernate, and is easily recognizable by its long body and short tail.
These four types are further classified into various sub-species and color mutations, creating a wide variety of unique hamster appearances.