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Heathland Natrix / Lake Gravel pit natrix |
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Posted: 09 Jun 2003 at 9:23pm |
I spent all of my youth round the lakes and gravel pits of Shepperton and Chertsey , and could reguarly see the same grassys basking in the same spots. These were quite often areas cleared and leveled for fishing . But , when it comes to heathland natrix , rarely do i see them in the same spot (Although there are the odd few). It seems to me that these grass snakes are somewhat more nomadic , and they are usually encountered as a surprise when just walking looking for berus . Are heathland natrix nomadic , having no particular basking spot? Alan |
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test
Member Joined: 29 Apr 2008 Status: Offline Points: 1 |
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That's answered a bit of my puzzle at hindhead, the older females using favoured basking spots around the pond, (though they are now very limited) and younger grassies popping up all over the hillside, sometimes grouped sometimes singularly - I had been wondering why the natrix on the hillside are smaller and never in the same place!
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Hi Tony , thanks. Do you know if there is a big difference in prey with regards to lake/ heathland natrix? I would expect Lake /gravel pit natrix to eat far more amphibian prey , while heathland grassys would eat more reptiles and small mammals.? Cheers, Alan |
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Hi Tony, Now that is interesting. Back when I lived in Shepperton I kept a number of grass snakes . I wouldn't do it these days , I was a teenager ,and now I prefer leaving them wild. Anyway, back to the point. I offered one of my captives a toad once , then watched as this toad inflated itself with air . The grass snake could not swallow so he spat it out , I never offered toads again after that. I did have two very large chunky females that would always favour mice/ voles over amphibian . As grass snakes do not have the ability to constrict I would stun or pre-kill them before throwing them in for fear of the m being bitten. It'll be interesting to see the results of this scat study. Cheers Tony, Alan |
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test
Member Joined: 29 Apr 2008 Status: Offline Points: 1 |
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Hi Alan, Tony I had a short term captive Natrix natrix last year (one of the stars of the ID pages ), though 100% with Alan's feelings that they are not one for captivity, I was interested in feeding responses and possible captive breeding, so here are some observations, On capture regurged full grown Common Toad Attempts at feeding defrost mice and pinkies all failed, one take on a pinky using forceps but rapidly dropped. She would take stunned fish, but only if some movement occured such as fin spasm, dead fish was examined but never taken, even if very fresh. I've only ever seen regurge of amphibians in the field - though am aware that there are records of regurge of mammals and fledgling birds for N.n (and a recent one for conspecific in the wild, though I personally think this may have been a case that 2 went for the same prey and one came off worse than the other, though the victims head was entirely missing, so might have even been carion), I've also seen captive Natrix show an interest in rodents that had been long dead and smelt terrible, yet have never seen one actually taken. Interestingly she was sloughing every 6 weeks in captivity, how does this compare with them in the wild? |
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Hi Gemma, Tony. Gemma, The large females that I kept were fed on WC Mice and voles . Maybe this is why yours refused rodents . Some exotics will only eat wild or brown rodents. I managed to breed natrix once in captivity , if you could call it that. I had a large area in my garden for them enclosed with corugated iron and such. Twenty two eggs , and 18 hatched successfully ! One Double headed lasted just over two days. Tony , I have never observed or kept coronella but , always thought they used the coils as a means of restraint. Is it true what I read that they will eat young adders? Are they skillfull in their bite and restraint of adders , or immune to the venom should they recieve a bite? Cheers, Alan |
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Sorry , up above should read "Some exotics that i've kept in the past will only eat wild or brown rodents". I wasn't saying natrix is an exotic
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Hi Tony , So yes, they probably are immune to some degree then . You would think that the fangs themselves could cause serious problems . After all , to prey items most viperids fangs must be like large daggers. During my time keeping venomous i'm sure some kills were due to the stab itself hitting some vital organ rather than evenomation. Particuarly in the large bitis of course. Mind you ,(Going slightly off in a different direction here), for effeciency and speed of kill , C.d.durissus came out tops everytime. Did you ever study Durissus in your time at the serpenterium? Cheers, Alan
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Alan Hyde
Senior Member Joined: 17 Apr 2003 Location: United Kingdom Status: Offline Points: 1437 |
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Hmmm, I didn't think C.d.terrificus had changed . Wolfgang? Sorry to hear about the death of those animals , that's really upsetting. Anyhow, thanks for your thoughts, Alan |
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Wolfgang Wuster
Senior Member Joined: 23 Apr 2003 Location: United Kingdom Status: Offline Points: 374 |
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Hi Alan,
At the moment, nothing has changed, but we are working on it. Not entirely sure yet what the end result of it will be in terms of nomenclature, I am more interested in the biogeographical angle at the moment. The piccie shows a preliminary DNA tree that we published last year - we have a much more in depth study coming through, some of the details of the tree below will change with more our more comprehensive data. Reference: W_STER, W., M.G. SALOM+O, J.A. QUIJADA-MASCAREÐAS, R.S. THORPE & B.B.B.S.P. (2002) Origin and evolution of the South American pitviper fauna: evidence from mitochondrial DNA sequence analysis. In Biology of the Vipers (G.W. Schuett, M. H÷ggren, M.E. Douglas & H.W. Greene, eds.), pp. 111-128. Eagle Mountain Publishing, Eagle Mountain, Utah. Cheers, Wolfgang |
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