Whisker Biting?

Question
I currently have three female mice all living in the same twenty gallon aquarium. Two are from the same litter and are about two months old now. The other is three months old. They are all active, healthy, and very tame.

Recently, one of the younger mice lost all of her whiskers. Her cheeks are now bare pink patches of skin. This happened rather suddenly, within the span of a single night. The other two both still have their whiskers. There aren't any signs of mites or similar parasites. The one who lost her whiskers was the most dominant of the group. I can't see any scabs or infected tissue either.

Is it possible that she is no longer the most dominant and whoever won overgroomed her as a show of dominance? Should I separate her? I don't like the idea of keeping a mouse on her own.

Aside from having bare cheeks, she has no other health issues. She's just as active and as happy as the others.

Answer
Dear Alaric,

Mice do do that.  It's called barbering.  Sometimes they 'cut' the fur too.   One of the other mice did rise to the more dominant position, if only temporarily!  But there is no reason to separate them.  I never separate mice unless there is blood drawn or somebody is depressed.  They have their little rites.

The mouse without whiskers will be fine.  Whiskers are important for a lot of things and it's kind of a bummer for her, but she lives in a nice cage with food and friends and no predators, so she isn't actually at much of a disadvantage.  I even had a mouse whose lovely long whiskers all burnt off (she sniffed a candle at dinner!) and I never noticed any different behavior in her.

The main reason not to separate them is that mice are very much social animals and any mouse living alone will be sad.  Thus it is better to lose your whiskers than to lose your loved ones.

squeaks,

Natasha