pet rat bite

Question
My 12 year old daughter has a 3 year history of very positive experiences with her pet rats.  She currently has 2 rats (20 month old "blue" male rats purchased as youngsters at PetSmart) who have always been docile and friendly.  Last night, one of the rats (he is the dominant of the pair) bit her without provocation.  The bite was very near her eye and drew blood. She is certain that he was not provoked and that he meant to bite her.  We have noticed that this rat has been bullying his brother increasingly over the last 6 months - but otherwise - he shows not sign or symptoms of physical or mental changes.  We have a veterinarian - and he gave the rat a clean bill of health earlier this year.  The rats have not escaped or ever been exposed to other animals. There are no know stressors in the environment and nothing has changed recently with their cage or circumstances. The wound is small and not showing any signs of infection this morning.
Question:  Are you aware of any physical illness rats may have that could cause aggressive behavior?
Are there concerns or precautions we should consider taking?
Thanks, Melisa


Answer

Rats love eyebrows and eyelashes.  They all do. They are fascinated by them. I have never met a rat in my life that has not gone for my eyebrows.  I have a feeling the rat that bit your daughter was going for the brows. I really cant see it as being any form of true aggression since they are as old as you say and never really had problems before.  Aggression issues show early, not late in life.  However, if the rat is injured, they can bite as a defense mechanism.Sometimes brain tumors can cause aggression but this is not real common either. Most males prefer to hold an alpha status and will usually make this known to the other males in the colony.                                                                                                Females also tend to be more aggressive when pregnant or when they have a new litter of rat pups.  


I will assume the bite didnt swell too big or bruise? Also, at her age, I am going to assume she is current with her tetanus shot too.  I have been bitten breaking up some huge rat fights before and although it hurts like heck, never had  any problems with infection etc....

One important thing to tell her is to not be scared of him and even if she is, dont let him know it. This may make him feel shy around her and even fearfful of her.  Rats pick up easily on negative feelings etc... due to their lack of trust in humans that we usually have to earn when we first bring them home.