Nesting Behavior

Question
QUESTION: Hi Sandy,

My 9 week old hairless male, Harry, is now sharing a cage with my 2 year old rat Belladonna (who I'm certain is post-menopausal). Lately one of them has been tearing up their cozy cup and using the fibers as nesting material in their igloo. Is it possible that even though Belladonna is so advanced in age and has already had one mammary tumor removed that she actually is still capable of reproduction? Or is there another likely explanation?

Thanks so much for your valuable expertise,

Joel

ANSWER: Joel

(My Joel, I presume?! :)  

I hate to be the bearer of bad news but the truth is, it is possible for a Doe whos estrus cycle has stopped to get pregnant, although the pregnancy may not develop normally.

I usually If tell people not to trust males and females together that are intact no matter how old the female is. Some rat owners know when their Doe is in heat due to the way she wiggles and vibrates her ears. A  Female in heat may have certain characteristics in her behavior that she only displays when she is in heat and when these specific actions diminish, they assume its a safe bet her estrus cycle has halted as well.

A vet can put an end to the suspense by taking a blood test to determine if there is a pregnancy by the presence of specific hormones.

Is it possible Harry is the one pulling out the cozy cup stuffing or did you see Belladonna doing it? Have they always had the cuddle cup? Do they have other things to use to nest with prior to them destroying the cuddle cup?






Sandra

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

QUESTION: Hi again,

I haven't seen who is pulling the cozy cup apart. It may very well be Harry as we both know how destructive bucks can be. The cozy cup was there when I still had Ivy with Belladonna, and although Belladonna seemed to be intent on tearing bits and pieces out of the cozy cup before Harry was in the cage, it seemed she was just trying to "rearrange" the interior of the cozy cup for ultimate comfort. Now that I think about it, Harry might have simply been mimicking this behavior to the point of destruction of the cozy cup. And Belladonna, being such a tidy little rat, simply took the mess he made to the igloo to store it.

I really always thought Bella was infertile to begin with simply because she was about 8 weeks old and housed with similarly aged males when I bought her from the pet store. Since she wasn't pregnant then I always figured she probably wasn't capable of becoming pregnant. Between that and her advanced age I was cocky enough to think I could put him in with her. I guess now I'll just have to sit back and see what develops.

Thanks again,

Your Joel

Answer
Your welcome


Also, just because she is not exempt from pregnancy, that doesnt mean her chances are high, either. Lets just say that she has more of a chance that she is NOT pregnant more than  the chance that she IS.
Make sense? :)

I guess we will both see, wont we?  Thanks for the sweet things you said about me too.