Tail Chewing

Question
My rat is almost 3yrs old and until recently has been active and playful and energetic. That recently stopped. She stays in her house all day except to come out for food. Constantly chews on her ears and tails, it's gotten really bad her tail is covered in scabs. I've tried playing games with her buying her toys. She doesn't take interest in anything.

Answer
It sounds like she may have an external parasite such a mites or lice.  Mites tend to bite around the ears and tail and it can get very itchy.  She may be scratching at herself for this reason.  To treat her, buy some Advantage or Revolution from your vet, just one tube of the puppy / kitten kind, and put one drop on the skin at the back of her neck, then another in two weeks.  This will kill any parasites she may have and hopefully stop the itching.  Make sure you clean out the cage really well during the two weeks to get any that may have jumped off.  To prevent reinfection, freeze all bedding to be used for 3 days.

If that doesn't help, she may have become senile in her old age and has a psychological problem that is causing her to injure herself.  Many rats do not make it to three, so she is quite the senior citizen.  It sounds like you are doing the right thing by keeping her from being bored, so my guess is that it is mites that are bothering her.  If she doesn't get better and is still not playful and listless it may simply be due to age.  It wouldn't hurt to have a vet examine her, an exam is usually around $30 for a rat.  If she is just getting old she may be acting strangely and if she is hurting herself for no reason you may have to consider euthanasia.

Hopefully it is just mites and she will go back to normal!  Good luck!