This article is from the Winter 2003 AFRMA Rat & Mouse Tales news-magazine.

By Helen Pembrook

Molly Rice, St. Paul, MN
QI’m writing to you because I’ve got a little question. You see, I’ve just bought another adorable fancy rat a couple weeks ago, and he looks young. I’ve decided to call him Romeo because he’s so adorably cute. Anyway, my female rat Gorgeous doesn’t take a liking to any other rats at all. I let her smell him, but I don’t put them together or close enough to fight. Every time Gorgeous smells him and you pick her up, she squeaks like she thinks you’re going to hurt her. My question is, why does she squeak after she’s smelled Romeo, and how could I at least try to get her to get along with him. Also, what is the oldest age that a female rat can have babies? I would really appreciate it if you answer those three questions and write back to me with a little bit of information about those things. Thank you for your time.

AFemale rats usually go sterile after 12–14 months of age if they have never before been bred. You cannot count on this though, as it is not always the case. They should not be bred after 14 months as it becomes hard on them. Most rats are no longer fertile after 1½ years of age. It would be best to get another female rat as a companion for Gorgeous, and another male for Romeo so you don’t have any unplanned litters. Rats come into season every 4 days and when the female is receptive, the male is very quick to breed her. Males are capable of impregnating a female when they are only 8–10 weeks of age, so even though Romeo is young, he may be old enough that you could end up with lots of rats in a very short time.

It may be that Gorgeous just doesn’t associate well with other rats. That may be her personality. The only way she has to communicate with you is through squeaking, so she is letting you know she does not like this new ratty in her house. If you want to try and introduce them (or new companions with each of them), do so in a neutral place (the bath tub, a clean aquarium) with another cage or container near by so you can have a place to put one if it does not work out. They may fight a bit, lots of squeaking and bouncing. This is just a way of establishing who’s the boss. One will submit by laying on its back and squeaking and the other will establish dominance by looming over it. This may look violent, but as long as there is no blood, it is normal. If you see blood, separate them immediately by grabbing one by the base of the tail and putting it in the waiting cage. Don’t try to grab them and lift them up like normal as you may get bit. Let both rats calm down awhile before handing. If this happens repeatedly after several attempts to introduce them, then it is not going to work and you might as well accept that Gorgeous is just a people rat.