Daughters Dwarf Hamsters - one has died

Question
QUESTION: My daughter has two dwarf hamsters both male that she has had for just over a year.  She keeps these at her dads house and I occasionally take care of them if the go on holiday.  The last couple of times I noticed that the white one has marks on his body, and was told that the smaller grey one would sometimes bit the white one, but this did not happen all the time.  I have only looked after them a couple of occasions during the year.

I have looked after them this time for 4 days now and when I went to the cage this morning the white one has died.  It looks like it has a cut on its shoulder and marks around its face, but I don't know whether this has happened before or after its death.

The other hamster (grey) seems a little unsteady on its feet, but looks ok and has no marks on it at all.

I was hoping that you could shed a little light on this.  I'm presuming that the grey hamster has attacked the white hamster, but confused as to why it would happen after a year of being together, and wondering why the other hamster is now a little unsteady on its feet.  Could the move to a different house have caused it? they remained in the same cage, but could have been upset by the travel, and I'm sure the first time I noticed the bite marks on the white hamster was during a stay at my house.

Thank you for any advice you may be able to provide.

ANSWER: Although it is rare that males will fight, rather than females, it is the most likely cause of death. It is possible, but not likely, that the travel stressed the grey hamster who, in return, attacked the white hamster, but there is no way to know for sure.

---------- FOLLOW-UP ----------

QUESTION: Thank you for your response,

Its been over 24 hrs now since the death of the white hamster and the grey hamster is till unsteady on its feet, specifically the back end, every few steps the back end seems to flop to one side. Its not stopping the hamster getting about, however he is not on his wheel as much as he normally is.  As there are no marks on the hamster, could this just be a result of the fight or could there be anything else wrong with the hamster?

Answer
After hamsters fight, the aggressor should be fine. Either the white hamster put up a really good fight, or something else is the cause. I assumed the sores on the white hamster looked like battle wounds from another hamster. If the sores did not look like bite wounds or scratches (more like a skin condition) then the grey hamster could be headed in the same direction. My best suggestion  is to see a veterinarian to get a proper diagnosis, and also clean the cage extremely well (without using bleach) to be rid of any existing bacteria or virus.