Hatched Already?

Jon hi,

Ok, take a for instance: It generally is accepted (maybe not by you?) that female Grass Snakes mate once every two years - biennial.

Ok then, if the females were being left unfertilized in the spring of the years in which they were supposed to breed because they could not find a mate - ie; that in local breeding groups the populations had been reduced to a point where interaction was non-existent / minimal, then it stands to reason that when a mating opportunity arose, the female will take it, irrespective as to whether the season was autumn - and the reason for this is so that the sperm can be stored.

I'm not saying it is usual - far from it, but what I'm saying is that maybe, just maybe, we are witnessing a natural response to imposed conditions. Nature does this all the time, it is basic - like mass migration in response to the oncoming of winter or seasonal diets. The animals do not start migrating when the cold weather has arrived do they?? Well, do they?? No. They anticipate the arrival because it is written in their DNA.

Therefore, it follows that if the snakes notice that food is becoming scarce in the late summer / autumn periods - an automatic in-built DNA response COULD BE to ensure an early start for their eggs.

In answer to your question - I have not personally heard of any obviously gravid Garss Sanke being found at hibernation sites in late autumn BUT, if the female had only released stored sperm to the eggs as they were about to enter hibernation, how would you know?? Xray them? Kill them and examine the remains perhaps? Of course not.

It is conjecture. But what is not in doubt that neos are being found in June that are 150mm ish. I have found several myself of this size. Explain that - and please do not suggest that they were born small the previous year, because if that were the case, professionals such as yourself would be turning up neos that were maybe as small as 120mm at hatching!!! have you??? I think not.

Cheers

Rob 

Hi Rob

How specifically are you suggesting grass snake behaviour is altering?

Regards

Stuart

Interesting stuff

However I believe that the assumption that because a snake is the same size in Spring as a neonate that it must of just hatched is misguided.

From my own observations of egg laying/hatching on man made manure based breeding heaps and witnessed breeding/brumation behaviour of adult snakes in captivity then I think it far more likely that these young snakes are from the previous year and that they have just not yet eaten enough to put on significant weight or length.

As regards the above paper the peak in mortality in Spring surely only proves thats when the young snakes are on the move and not when they hatched? 

Regards

Stuart

Stu / Jon hi,

I would like you to think about what you have said and reason it out.

Take a human baby. In order to keep it alive (ie; to prevent starvation), it requires a given amount of calorie / energy / food input, yes? Do you agree?

Right. Babies of any species that do not receive enough of this develop malnutrition and die.

But; if they receive the very minimum sufficient enough to keep them alive, they grow!! It might not be as much as a well fed baby, but a one year old is always greater in dimension than a one month old, unless that is, it had died.

I'm sorry guys logic says you are wrong. A neo Grass Snake that is one year old will never be 158mm or less, impossible, it would be dead. And as for the coldest winter in 27 years being responsible - how? They are in hibernation for that period?

I'm surprised at you Jon, I would have thought logic must play a large part of your studies?

Cheers guys.

Rob 

Hi Rob

Nothing personal but I'm afraid I disagree with your analogy and logic.

"Take a human baby. In order to keep it alive (ie; to prevent starvation), it requires a given amount of calorie / energy / food input, yes? Do you agree?"

-Well of course I agree,however,a comparison between the homeostatic requirements of a human baby and a reptile is in my opinion irrelevant.If I remember correctly approx 80% of a mammals calorific requirements are to maintain body heat alone.Furthermore a human baby has little inherrant energy supply.Reptile neonates often have the remnants of an absobed yolk sac that could be used to sustain the animal through a period of brumation.

"But; if they receive the very minimum sufficient enough to keep them alive, they grow!!"

-I believe this is incorrect-it is possible to acquire enough calories to maintain bodyweight....growth is only possible when there is a surplus to maintain life.

 "A neo Grass Snake that is one year old will never be 158mm or less,"

I believe the post brumation neonates are being found are approx six-eight months not a year old.

"within three hours of hatching the neo Grassies would have dispersed from the incubation site"

Rather a specific time to such a blanket statement that by its very nature has to be incorrect and misleading. I have found brumating neonates at the incubation sites in January. The heat from the composting process is no longer discernible. I think some hatchlings disperse rapidly,some do not.It is this variation in individuals behavior within a species that allows them to survive and exploit new and varying conditions.

And I stand by what I said in my previous post that the peak in mortality on the road only proves that snakes are moving and nothing more.

Sorry for such a long post

Regards

Stuart