Barbering in pet mice

Question
My much smaller mouse is barbering its larger cage-mate.  They are both females.  We had them for 4 months before this started.  We now have to separate them since the barbering has gotten so bad there is blood and it looks like parts of the ears have been chewed off. Is there any other remedy for this besides separation since it is so sad to see them apart?

Answer
You did the right thing by separating them. It is quite unusual for females to fight and very strange for the fighting to start after having them for 4 months.

Double check they are females, some stores will sell males without realizing. Make sure you haven't done anything different such as change the amount or brand of food, move the cage to a different area or move them to a smaller cage. The fighting could be stress related - check the cage is out of reach from small children and other pets as well as noises and drafts.

There a few things that may help. Feed them plain boiled rice for a few weeks if you think they are fighting over the best 'bits' of food. A larger cage with more hiding places such as tubes and boxes might help as they can each have their own territory.

Talk to the pet store and see if they have experienced any violence related problems with their females. Your vet may be able to provide you with a calming remedy and possibly know what triggered this behavior.

Even though it was the right thing to do, mice are social creatures and need the company of other mice or they will be stressed, depressed and lonely. Take your larger mouse to the pet store and see which other mice she gets along with as she isn't the bully.

I really hope this helps, please feel free to ask any more questions.