My Male neutered rat is still mounting my female

Question
HI,

I have a boy and girl rat. The girl recently had a litter and the boy was neutered (5 weeks ago for both).

Apparently my female was in heat today and my boy has been mounting her all night. I am worried because I do not want another litter. I am hoping that he is sterile since he no longer has his testes.

I am surprised he has any interest in mating! So my long winded question is, can he still impregnate my girl? And is it normal for them to still be mating?

Answer
Hi Dyane


To be honest, the male sperm dies within 8 to 10 days after neutering.
The vet suggests waiting 3 weeks for many reasons: For hormones levels to drop, for the rat to heal completely and for any old patterns of behavior to be forgotten.


Normally, sperm will exit the testes, entering into the epididymis. This is where they remain till they are mature enough to be fertile. They only remain in the epididymis for 42 days and after that they die off.

When the rat is neutered, the sperm that is in the epididymis will die off as the epididymis deteriorates. This takes several days to occur but it usually occurs in a few days.  

Anyhow, dont worry about the female getting pregnant. The male is mounting only to show dominance.  This should decrease in time. Its more behavioral than anything.