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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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Stu / Jon hi. Great, a reasoned and intelligent debate without mud slinging . Refreshing. But I'm afraid we're going to have to agree to disagree. I hope we all continue though to study and try to prove the answers we're all seeking. In terms of growth, skeletal growth and cartilage extension has nothing whatsoever to do with weight. We are talking length here. The osteocytes in a neo Natrix cannot be muted or held back - bilogical fact. If the snakes diet is so lacking in calcium, phosphorus etc, so as to cause Metabolic Bone Disease (MBD), the knock on effect is that parathyroid hormone will increase in the bloodstream causing irregular heart rythms and death. So, if a neo snake has received enough food to keep it alive, the skeleton and cartilage will have grown, biological fact. Sorry lads, admit defeat, no neo Natrix will ever be a year old and be 150mm - unless it is dead. R |
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RobV
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herpetologic2
Forum Coordinator Joined: 15 Jun 2004 Location: United Kingdom Status: Offline Points: 1511 |
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Hi rob
Not a problem - though we are not talking about 1 year old grass snakes - we are talking about snakes which are 6 months old after hatching - this could be the case if grass snakes hatched in late September/Early October - by June the following year the snake would have been 7 months old. However the weather this year would have made it difficult for the snake to have found food early enough to have put on weight or length significantly. neonates have a yolk sac which sustains them prior to overwintering - this winter was a hard winter and would have meant a low energy expenditure due to the dormancy of the animals over the winter months so it is possible that the snake remerges around the same length as when it was born sorry hatched -/+ 10mm J |
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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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Jon hi, I would agree with you IF the neos hatched in say late September / October and went straight into hibernation without much actvity... then it is possible, but definitely +10mm. Rob |
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RobV
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sussexecology
Senior Member Joined: 30 Sep 2010 Location: United Kingdom Status: Offline Points: 411 |
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I would agree with you Stuart I have found similar sized grass snakes this month, so believe that these must be from last year. I just feel that it's way too early for them to be from this year, but having said that it has been unseasonably warm and everything seems to be about 3 weeks ahead of what it should be. Even so, I think it's still too early for young of this year to be around. |
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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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There is no doubt there are some in this audience at RAUK who could be compared to those that maintained the earth was flat when Aristotle suggested it was round.
If the notion of late May hatching is so alien to your thinking guys and you simply cannot accept that there a possibility a female Grass Snake can utilise an autumn fertislisation to advance the oviposition of eggs and therefore an earlier Spring hatching, then tell me this...
Why would a Grass Snake mate in September / October if NOt for such a purpose???
Pleasure maybe!! hahahahaha
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RobV
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stuart
Member Joined: 26 May 2005 Location: United Kingdom Status: Offline Points: 31 |
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RobV
I do accept that a female grass snake may be able to utilise sperm stored from an Autumn mating, I just think it unlikely. Certainly my observations of Autumn matings in captivity have never yet resulted in a clutch being laid in the following Spring. I still feel that on the balance of probabilities it is an unlikely occurrence. Do you have any evidence to back up your opinion?
I would suggest that the Autumn matings are a result of males acting on confused instict and opportunity. Or just just males doing what they do best!
On a personal note, I think that on a forum with a such a low volume of traffic ridiculing people who have a different opinion to yourself is only likely to stifle further intelligent discussion. I really enjoy discussing my observations with other like minded individuals so please in the interests of encouraging further input keep your posts respectful.
Regards
Stuart
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GemmaJF
Admin Group Joined: 25 Jan 2003 Location: Essex Status: Offline Points: 4359 |
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I considered one factor.
Are there not studies that show hotter incubation results in smaller hatchlings? Could it not be that in recent years the hot summers have resulted in smaller than average hatchlings at some sites i.e. shorter than optimal incubation? We then see them the following spring and are surprised at the small size? I'm not saying Rob is wrong, it's just another factor for the debate. I took a look at monthly temperatures and too think the spring laying seems unlikely but not impossible.
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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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Stuart,
hi. I have c ouple of comments to make, I do hope you don't mind. Firstly, I'd like to ask you, what are you doing with Grass Snakes in captivity in autumn? Let them go Stu, there's simply not enough out there to risk keeping some banged up and losing them in the winter.
Secondly, there are some on here that are very quick to ridicule my suggestions (just read this post from start to finish to feel the 'tone') and so my 'ribbing' the other members is all good hearted stuff and I'm sure no one would take offence. If they did take offence, then they should put it back as soon as possible before all the cattle get out!
Have a good one dude, happy hunting - let the brothers go - as they say in an old paul newman film.
Rob
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RobV
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will
Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1830 |
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Let's link up a few threads...
grass snakes may (either due to climate change or as a regular feature of their biology, not recognised til now) mate in autumn and delay egg laying til spring. Smooth snakes may delay giving birth til the following spring/summer after overwintering whilst gravid. What about adders? do they do the same thing? the biennial nature of adder /smooth snake (and grass snake, if Rob is correct) breeding in our native female snakes is well known, but is this due to them replenishing their reserves in the 'off' year, or is it because they carry their eggs/young through the winter (or both)? perhaps there's a common theme here, in terms of similar solutions to the same problem of living in a fairly cool country? just conjecture, but could be worth investigating if only to eliminate the possibility that all 3 species show the same aspect of their reproductive behaviour. |
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Iowarth
Admin Group Joined: 12 Apr 2004 Status: Offline Points: 743 |
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There have been some fairly polarised views on this thread - mainly revolving around the probability/possibility of Grass Snakes laying eggs fertilised in the previous season. Now, I have absolutely no knowledge of this BUT, throughout my many years working with lizards I have come across several proven instances of animals carrying eggs/young through hibernation after a late summer mating. These species have included both Sand Lizards and Green Lizards emerging well plump from hibernation and laying eggs before the end of April, having been observed mating in the preceding October. Much more recently, with a captive Sceloporus cyanogenys (a viviparous US Fence Lizard) mating was observed in September last year. Both male (the only male) and female went into hibernation in November and the male died in hibernation. Nonetheless, the female produced five healthy young three weeks ago. Clearly, therefore, at least some lizards will give birth/lay eggs as a result of a mating late in the previous year and under these circumstances I don't believe we can dismiss the possibility of a snake species doing the same. Chris |
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Chris Davis, Site Administrator
Co-ordinator, Sand Lizard Captive Breeding Programme (RETIRED) |
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