Keeping hamsters in a social setting depends greatly on the breed of hamster. Dwarf hamsters are generally gregarious; if introduced at a young age and kept with same-sex members, they cohabitate well. The more common Syrian hamster, however, should not share a cage.
When young, Syrian hamsters can co-exist; upon reaching 8 to 10 weeks of age, they begin fighting for territory and may fatally wound each other.
Dwarf hamsters are small enough – generally 4 inches in length at maturity – that they should be kept in a glass enclosure, as they can escape between the bars of larger hamster cages. Both varieties are nocturnal.