Most hamsters can live together when they are young, but get more territorial as they get older. Fights can be brutal so it's recommended that owners take extra precaution when housing two or more hamsters together. Some species of hamster like the Winter White Hamsters are not as territorial as the other dwarf hamsters and can live peacefully in small groups.
The best solution to deal with territorial hamsters is to separate the hamsters as they may fight till the end. Signs of territoriality are marking objects with their sides or bellies. Also provide lots of toys and ample space for the hamsters to ensure that they can be otherwise occupied while living in the same enclosed space as another hamster.
Addiction to running on hamster wheel
While this activity is not a negative activity, excessive running can become problematic in instances where the female hamster is pregnant or has just given birth. Addiction to running on the hamster wheel can cause the female hamster to neglect her babies or her pregnant state.
Additionally, addiction to running on the hamster wheel can give your hamster feet sores. The solution to this is to remove the hamster wheel for a period of time.