Mice and Barbering/Dominance

Question
I am doing my science fair project on mice and dominance, and I would like to know more about barbering and how animals show dominance. My two mice are Marshmallow and Oreo. Oreo is the dominant mouse,I know this because she mounts and barbers Marshmallow. Marshmallow really doesn't care, that's why I call her Marshmallow, because she is calm (and squishy!#. I would really like to know more about this and please get back to me soon! #soon is code for less than 15 days! LOL!! that's when its due, sooo yah!)
THANK YOU!! XD
                            ~Sarah

Answer
Hi Sarah,

I can't be a source or anything, but I can tell you what I've picked up from various experiences with mice.  For source materials, I would try searching databases for papers on: mouse dominance, dominance displays in other animals, mouse colony hierarchies, mouse barbering, mouse social structures, mouse weaning time, mouse fathers, mouse hormones and dominance behaviors, and the genetics of mouse barbering.

Here's what I know:

There's speculation over whether barbering is a learned habit, stemming from time with the mother who may barber other females or from cage mates who barber, or a genetic one.  To be on the safe side, mice that barber are not typically bred from.  This is not because barbering causes harm - but because it may be a disorder, causes an obvious loss of fur, and may indicate the presence of more aggressive dominant behaviors.  Note that barbering does not usually involve scabbing or a loss of blood - the hair is chewed away, not pulled.  Barbered skin will appear healthy and not irritated.

Females who barber will usually barber every other submissive female  in the cage (there is usually only ONE culprit, though others may pick up the habit if the dominant mouse is pulled) in a specific pattern to that mouse.  Every mouse she barbers will look the same.  Some will just barber the face, others will do intricate designs over body - mostly the head, neck, shoulders, and front arms/chest area.  My personal opinion, though I really have no idea, is that it may have something to do with scent.  Mice are very sensitive to smells, and fur holds smell.  By barbering away the fur, they may be reducing the smells of the other females in the cage.  I'm not sure how true that is, though, so I would really try to find scientific research on it before taking that as fact.

I have not seen or heard any evidence that other dominant behaviors, such as mounting, chasing, or aggression, are learned, though it's commonly accepted that they are genetic, since overall temperaments appear to be hereditary.  Of course, there are substantial writings floating about the internet that point to the amount of time spent with the mother and father mouse affecting the disposition and mental state of offspring.  I would definitely do a google documents search, or search on a journal database, for recent writings on the topic!

Males can barber, too, though it's usually a result of overgrooming or a sexual behavior (some males groom females when trying to court them).  This does not necessarily have to follow a set pattern across the coat like females do.

Not all animals show dominance in the same way mice do, but they do have important insights to offer (that's why we use mice so much in science!).  Hope you dig up some good sources, and good luck on your project!

-Tam