Why infertile eggs/how to improve fertility?

[Rich Z]

In the wild, I believe slugs are formed so that if an egg-eating predator comes along, its hoped the predator eats the slugs and not the fertile eggs. Basically, its increased chances for the healthy eggs to survive.

Hmmm...

Firstly, a predator is not going to simply eat the infertile eggs and leave the good ones alone.

Secondly, I have found my share of gravid female snakes in the wild and to date, I have NEVER had any of those snakes lay any infertile eggs. None. I have also found clutches of snake eggs in the wild and never found any infertile eggs in those clutches either. And on top of that, I have found quite a few clutches of hatched eggs and never found any signs of infertile eggs there NOR any babies that did not hatch out successfully. This is not limited to corn snakes, either.

Anyone else have any experiences along this line?

 

[paulh]

The one clutch of eggs I've found in the wild was 100% fertile. As far as I recall, fertility rates from my wild caught gravid females have been at least as good, and generally slightly better, than captive bred. Once I did a comparison of fertility rates from a wild caught female bullsnake over a four clutch period. First year, when wild bred, 100% fertility. Fertility was down to around 60% for the fourth clutch, one clutch per summer.

I have only once seen a wild caught, gravid female produce a 100% slug clutch. That was a bullsnake, and I think there was a high probability that she didn't find a male that breeding season.

 

[ecreipeoj]

Anyone else have any experiences along this line?

I haven't found too many clutches of eggs in the wild or wild caught gravid females, but they have all been 100% fertile. They were all Mountain King Snakes. I found three clutches of eggs that were already laid and they were all fertile and I caught two females that were already gravid and they laid all fertile eggs.

I guess the question is: Why are almost all eggs produced in the wild fertile and we have fertility problems in captivity? I think many of the possibilities have already been addressed.

One obvious difference in captivity is that, they are confined to one area and get constant exposure to their own fecal matter, which can cause a minor infestation to grow into a problem. In the wild they just crawl away from it.

They also have more exposure to other snakes which may be caring something which over time can become a problem, due to their confinement. I am sure that in the wild, snakes have some parasites, but they co-exist without any problems. In captivity, the parasites can grow to a level which can cause health problems and infertility.

 

[Rich Z]

So many things we don't know......

Why will we get 100 percent fertility from one female kept in the same conditions and then have a poor showing from another kept in nearly identical environmental conditions?

I think what we are seeing is that corn snakes can tolerate our fumbling attempts to meet their needs, for the most part. From the different ways that people will successfully incubate their eggs, it is fairly obvious that there is a wide latitude of mistakes we can make and still not kill off the eggs.

But I don't know of anyone with a sizeable group of corn snakes that gets 100 percent fertility, and 100 percent hatching every time. But obviously there exists a set of conditions that is an attainable goal for corn snakes in the wild, that may not be easily (or not at all) met in captivity.