hamster behavioural problems

Question
What does it mean when two dwarf hamsters appear to be aggressive to one another?  We have two in the same cage would that also become a problem?  

Answer
Hello, Silver, thanks for the question.

Well, you didn't state what kind of dwarf hamster you have.  
The Chinese dwarf hamsters would prefer to be housed alone unless they are breeding, just like their Syrian cousins.  

The Roborovski, Winter White, and Campbells species of russian dwarf hamsters do not mind company, and do well in either single sex or mixed sex groups of their own species.  Sometimes, two hamsters, just like two people, just don't get along, even two sisters, or two brothers, or a mother and a daughter.  The two may get along with any other hamster you put them with, but together the fights just never seem to stop.  I've rarely seen russian dwarf hamsters fight to the death (but it will happen, espcially in mixed sex groups where the number of females is much smaller than the number of males), but they will put some nasty wounds on each other, and the problem is that the smaller hamster usually becomes very fearful.  He or she gets so used to being on the defensive all the time that they may even bite their handler, even if before the fighting started they had the sweetest temperament in the world.  They just get so used to being beaten on, that they think every touch is something coming to hurt them.  And never try to break up a fight with your bare hands - the most nasty hamster bite I've ever recieved was from the sweetest male hamster I have, when I was trying to sepearate him from a fighting cagemate.  I'd trust him with a baby, and he had never bitten me before and never has since, but when they are fighting, they don't know what they are biting.  (In fact, if you've ever seen a fight, they seem to usually fight with their eyes closed!)

If one was already an established hamster and another was brought in without them being properly introduced to each other on neutral territory, the established hamster feels that its territory is being invaded and may act aggressively toward the interloper, until they get to know each other and settle down.  (Again, though, sometimes this is not the case and they won't stop fighting.)

Russian dwarf hamsters like to have company, but they don't absolutely need it.  If your two hamsters do not stop fighting, or if blood is drawn, seperate them into two cages.  They will be fine with only you as their playmate.

If you have Chinese dwarf hamsters, however, I'd suggest you seperate them into two cages immediately before one is seriously injured by the other.