Breeding - sperm retention
 

i am a bit curious how this works. I read somewhere that a tortoise can retain sperm a year or even a few years after mating with a male. If, in theory, she had a new partner a year later, which sperm would she use? Would she have to first use up the old one and only then use the one from recent mating, or would it mix itself inside her and she would use a mixture of the old and new sperm?

The reason I am asking- my adult females currently mate with my youngsters males who are very keen and seem to enjoy themselves , but at the moment are not getting them pregnant yet. My females are laying eggs which are infertile which I am ok about it because the males are still too young so it doesn't worry me. But if I added an adult male, would they have to use the sperm they are keeping from the current mating first, or would they be able to produce fertile eggs? If it mixes inside them, then I would think that some of the eggs would be fertile and some infertile, until they dilute the immature sperm so much that the percentage of fertile would be increasing? Just wondering, just in case that I want to have some babies. At the moment I think it is blessing that they are not fertile because I am not sure what I would do with so many of them, but what if I wanted some babies in the future?

That's a good question and maybe one that Danny can help us with.

I agree, it's an excellent question and certainly one I'd never considered before. Now I'm intrigued as to the answer. Hopefully Danny will be able to shed some light.

It would mix and the female would use any sperm that would make it to the egg to fertilize it. Even in a single clutch there can be multiple fathers. When it comes to Testudo I've found they do not retain viable sperm for more then a laying season.

Danny

That's really interesting, thanks Danny. :)