Sudden Aggressive Behavior

[Amanda]

Hi everyone,
I have 2 female, un-spayed rats (Echo and Henni) who are both a little over 2 years old. They've been living together for about a year and a half and haven't had issues with each other aside from the occasional overly-intense grooming.
Tonight I noticed that Henni is biting on to Echo's skin and tail and pulling. I haven't seen her do this before and Echo squeaks when she does it. I don't see any blood, but when I catch her doing it, it looks like she's trying to tug pretty hard.
Do they need to be separated? Any ideas about why she might be doing this?

 

[Dena]

Not entirely sure, but I've heard pituitary tumors can alter their personality. Does she seem to be using her front paws OK? If you give her a treat, can she hold it and eat it with no problem? I know there are other things that may effect the way she's acting, but at 2 years old, that's what I would rule out first. If she has one, I know you may be able to help it with a medication called cabergoline or something like that. Prednisone. Hopefully Lilspaz, or SQ will comment soon, and can give you more answers soon. Sorry I'm not much help.