My rat bit me!

Question
QUESTION: Ok well I've had my rat for maybe a year or so and they have always been so nice and I took them out of their cage a lot (they're both girls). They have never ever bitten me before but just recently I stuck my finger in their cage and they bit me. I know that you are not supposed to do that but I've done it before and they didn't bite! I'm wondering what may have caused this?
ps. I am pretty sure they are both pregnant because we just got a male rat so I am not sure if that's the reason they are biting or not.

ANSWER: You said it. If they're pregnant, yeah, they're probably getting cage aggressive due to their hormones.

Why on earth would you breed BOTH of them? Do you realize you're going to have upwards of 30 babies? That's a ton of rats to take care of. Good luck!

---------- FOLLOW-UP ----------

QUESTION: I didn't try to breed both of them but i never relized how fast they can get pregnant. Next time I'll think before letting the male see them. The good thing is i've already found homes for all of the babies but they havn't had any yet.

Answer
Good; I'm glad you have homes for them already.. thats half the battle when it comes to litters.

Ratties go into estrus/heat every 4 days for 12 hours. So they can get pregnant pretty quick! If you want to keep your male and females together; consider having the male neutered. It's a simple procedure ranging from $80 to $250; and eliminates any potential litters.