rat biting

Hi, I have a female rat. She recently just started biting. She's always been a sweet, sweet pet, and all the sudden she is biting everything including me. She made me bleed once today. It may be because we just got another female rat that is now living with her. We haven't gotten up to go get another cage, so I'm trying to look for some cages around the house...Could it be that she is mad about the other rat? Or is it she is trying to make her teeth wear down? Please help. She was the sweetest thing, I don't know what happened.

I expect that it is the other rat that has made this change in behavior. If i introduced another rat with Tia, she would go mental. If it was her teeth, you'd probably notice her gnawing the bars of the cage or a wood block if she has one, and you'd probably notice her have difficulty in chewing her food and she would lose weight. Often, introducing small mammals that are not from the same litter is a risky thing to do as, especially with rats, they are prone to squabble with each other. I once had two roborovski hamsters that were from the same litter, and we had to separate them as one attacked the other quite badly. If you ever notice them standing and staring at each other or squealing then separate them immediately. Sometimes, rats do playfight, but believe me, you will know when it's the real thing. I would suggest separating them now just in case it does come to that, you may find that you'll have to 're-train' your rat into being handled again, but that can be done fairly easily using treats and gentle hands.

My rat is acting very territorial and mother-like with the new rat. She is like letting it sleep in the same place as she is, and is grooming it and stuff. I will have to change the cages asap.