Why do elapids have larger ventral scales than pythons?

Discussion in 'Australian Snakes' started by saximus, Apr 1, 2011.

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  1. saximus

    saximus Almost Legendary

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    Just one of those late night curiosities. Does this have something to do with the methods of locomotion or because of the methods of dispatching prey?
     
  2. $NaKe PiMp

    $NaKe PiMp Very Well-Known Member

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    that is an intersting question,a correct answer will be hard to come by as you will get lots of speculation off this forum,and my hypothesis is wide ventrals of the larger terrestrial elapids are suited to terrestrial snakes they spend alot of time on ground,may assist them to move more swiftly.
    lets google around and see
     
    Last edited: Apr 2, 2011
  3. Elapidae1

    Elapidae1 Very Well-Known Member

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    Yeah I always thought it was for terrestrial locomotion and speed.
     
  4. waruikazi

    waruikazi Legendary

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    Interesting thoughts. But then how do we explain the large(r) size of viper and colubrid belly scales? The last thing vipers want to do is move quickly and within that family there are terrestrial and aboreal genus'. And a similar story for the colubrids, except they are pretty quick when they want to be.

    I think you will have an easier time finding an explanation if you jig the question a bit. Perhaps 'Why do pythons have such narrow ventral scales?' would be easier. I think i have an explanation, i'll PM it to you sachs and see if anyone else comes up with it.

    Then you could ask why files snakes don't have recogniseable ventral scales.
     
  5. Elapidae1

    Elapidae1 Very Well-Known Member

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    Or blind snakes.

    Maybe it has something to do with reproduction. Or maybe dorsal scales offer better protection from certain types of predation, which may help to explain the ventral scales of File and Blind snake's
     
  6. waruikazi

    waruikazi Legendary

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    I'm pretty sure blind snakes have a discernable line of ventral scales. I removed one on Tuesday afternoon and i remember looking at them and thinking and thinking about how small they were.

    I think to get the explanation for ventral scale sizes you can't look soley at the ventral scales. You need to look at the scale sizes and scale counts together. If you stop thinking of pythons having narrow ventral scales but instead think of them as having very high mid body scale counts i think the answer is easier to come to. It is more than likely an evolutionary solution for increasing the size of prey items for an ambush animal that eats irregularly.


    Scales don't stretch, the spaces between the scales do. If there are more scales, there is more space which means more stretch. More stretch means the snake can eat relatively larger prey items.

    More mid-body scales a snake has the smaller the ventral scales look.
     
  7. Waterrat

    Waterrat Almost Legendary

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    I would say in arboreal and semi-arboreal species evolution selected against wide and large ventrals to aid locomotion.

    If you hold a terrestrial elapid by the tail, it has difficulties climbing up on its own body, pythons and tree snakes do it with ease.
     
  8. waruikazi

    waruikazi Legendary

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    I think that has more to do with the snakes strength rather than the scales. I've noticed with BTS and most pythons that they will be just about back on themselves before they try to climb themselves and they are much harder to knock off balance when they are coming back on themselves.Where as all the large elapids i've handled are easy.
     
  9. grimbeny

    grimbeny Very Well-Known Member

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    Surely it is an artefact of phylogeny?
     
  10. Waterrat

    Waterrat Almost Legendary

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    Which is what I said, evolutionary selection against large vetrals. Phylogeny is the carrier.
     
  11. waruikazi

    waruikazi Legendary

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    And as i said, an evolutionary solution for eating larger prey items.
     
  12. Waterrat

    Waterrat Almost Legendary

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    There is a gross inconsistencies anyway. Look at the size of the ventrals on this very arboreal pit-viper that feeds on small mammals, nothing too big.
     
  13. Elapidae1

    Elapidae1 Very Well-Known Member

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    Blind snake scales are uniform in size according to the field guide, personaly I have only handle R. pinguis and R. australis, there must have been a way to discern the ventrals from the dorsals though as I attempted a midbody count, I think it was colour but can't remember.

    Do we know for sure that Pythons can eat much larger items than Elapids?
    I think the midbody count is higher in pythons because overlap is greater not because the ventrals are smaller.

    This guy has some stretch going on

    Nice pic Michael
     
  14. Waterrat

    Waterrat Almost Legendary

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    Steve, blind snakes in entirely different category when it comes to scaletion. They are burrowing species and for their life style they need hard, glossy cuticle. They also feed on ant eggs and larvae, so they need a solid protection against stings and mandibles.

    I think pythons do eat larger prey than elapids but as Gordo said, the elasticity of the skin, not the scales is what matters when swallowing large prey.
     
  15. waruikazi

    waruikazi Legendary

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    I'm away from home atm so i don't have my books to check but i'm pretty sure there is data in 'The biology and evolution of australian snakes' that confirms pythons do eat relatively larger prey items.

    The mid-body count is higher because they have significantly more scales lol. I'm not saying that having more mid-bodies causes the ventrals tobe small but it may give that illusion.

    but this is all speculation on my part..
     
  16. Elapidae1

    Elapidae1 Very Well-Known Member

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    The Blind snake is more primitive than other snakes,it's scales also acting as an armour, Maybe as snakes evolved they required this armouir less and their scalation became more suited to locomotion rather than protection, Elapids being even more evolved than Pythons.

    Pythons may eat larger prey than Elapids but does that mean the Elapids can't?

    Here's a pic showing some of the ventral surface of a blind snake Gordo.
     
  17. waruikazi

    waruikazi Legendary

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    Yes i do think that it means they can't. That picture of the dugite is impressive.
     
  18. Nagraj

    Nagraj Well-Known Member

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    I'd like to see some evidence that scale size has an effect on either of the OP options.
     
  19. Waterrat

    Waterrat Almost Legendary

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    Evidence is not on offer today. I hope you have some to dispute our OP options.
     
  20. waruikazi

    waruikazi Legendary

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