missing whiskers!

Question
Last April I got two fancy mice to keep in my classroom.  They were both female, from the same pet store, and got along very well.  This summer I noticed one of the mice was missing her whiskers.  It seemed as though they had fallen out.  She was always the more skittish of the two.  I figured she was sick.  She didn't seem in pain or didn't act any differently.  Last week, that same mouse passed away.  I know they don't live very long and I figured it was because she was ill.  
 I didn't want the other mouse to be lonely, so I went to the same pet store and bought another mouse.  I introduced them to each other and put them in the same cage.  It has been 2 days.  This morning I noticed the new mouse is now missing her whiskers.  Is this a dominance thing by the first mouse?  They are sleeping together and seem to get along aside from the whisker issues, but I don't want to put the new mouse in danger and am willing to completely separate them.  Do you have any advice?  
Thanks so much!

Answer
Dear Rebeca,

Sometimes a dominant mouse chews the whiskers or fur of another mouse.  This is called barbering.  There's nothing to be done about it, but it does no harm at all, except perhaps to the lesser mouse's vanity!

Mice usually live 18 months or more before their natural death.  

Have fun with the mice!

squeaks n giggles,

Natasha