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Why Large Prey for Snakes?

Discussion in 'General Discussion' started by CTU2fan, Dec 22, 2014.

  1. CTU2fan

    CTU2fan Elite Member

    We've all kept snakes and know the general rule, feed a prey item roughly the girth of the thickest part of the snake. But conversely with lizards we generally feed smaller prey items, not tiny prey of course, but say I'm feeding a large monitor, I'd offer 2 small rats rather than one large one, even though it could physically manage the big rat. Just wondering why we don't do that with snakes, and why it wouldn't be easier on the snake to digest 2 smaller prey vs. one large prey the way it is with lizards.

    Just a kind of random thought I had, I like to kind of understand the why behind the guidelines we try to follow with out herps. I think it makes us better herpers vs. just reading and memorizing care guides.
  2. Darkbird

    Darkbird Elite Member

    Snakes are far better suited to swallowing large prey items than any lizard, even monitors. Think about it, a snake may take a prey item several times the size of it's own head, and they have adapted to do just that. Where as most lizards have adapted to smaller prey items, in many cases insects and small mammals. Varanids get away with taking relatively larger prey because theier brains are fully enclosed by their skull, even on the bottom if I understand it right. But even they can't take prey larger than their head.
  3. CTU2fan

    CTU2fan Elite Member

    They (snakes) definitely have the equipment to swallow large prey; it's a pretty big advantage for wild snakes, adding more (larger) animals to their potential prey items.

    I suppose having to hunt and overpower/constrict/envenom prey less often is an advantage.
  4. murrindindi

    murrindindi Elite Member

    Hi, Varanids certainly CAN take prey larger than their heads, the flexible skull and throat pouch enables them to do that. The braincase is fully protected by bone, but the bottom of the jaw is not (if that`s what you were suggesting)?
    They, just like snakes can also push the glottis forward in order to breath while swallowing large prey items.
    Two small mice will be digested in much the same time as one large one (usually within 24 to 36 hours).

    Here`s a short video of my (then) juvenile V. s. macromaculatus, he could have quite easily managed an even larger rat.
    Sorry about the very annoying clicking, it`s from the camera and I don`t know how to stop it other than turning the sound down on the vid (useless that I am)...
    Last edited: Dec 22, 2014
  5. CTU2fan

    CTU2fan Elite Member

    Fantastic salvator, yea I'd think he could take a bigger one based on his size, that rat went down pretty easily.

    I didn't know that, about their brain being encased by bone, is that unique to varanids?

    See I'd always heard/read/been told that with lizards multiple easily-swallowed prey is better, but apparently it doesn't matter. . Money-wise a single large item would be cheaper for the keeper.
  6. murrindindi

    murrindindi Elite Member

    I`m not suggesting to feed large items as a matter of course, just that they can ingest relatively large prey thanks to their adaptations.
    I`ve recently heard that it`s very stressful for appropriately sized monitors to swallow a large rat because the skin is too thick, that makes no sense to me at all, if they can digest bones etc, surely digesting skin wouldn`t be a problem?
    I have an idea that these people may have been referring to the fur, but again, why would it cause stress (it`s just roughage), and if a Varanid with the highest metabolic rate is stressed, how much more stressful would it be to most snakes which have much lower rates? Strangely, I don`t see these people touring the snake forums warning others not to feed large snakes on large rats (the mystery continues)...
    Edit: Don`t quote me on this but I have an idea that Tegus also have bone encased brains cases.
    Last edited: Dec 22, 2014
  7. Darkbird

    Darkbird Elite Member

    Love the video Stephan, and your absolutely correct. I was rushing a bit and did a poor job of explaining myself. I was more refering to the fact that snakes have the very flexible jawbones, and can handle prey several times the diameter of their own head, where monitors jaws are less flexible, and they can only take prey slightly larger in diameter than their own head. Does that make more sense or am I just totally off here? I'm just going by my limited current experience with the species I currently keep and my memories of when I tried keeping savs years ago. Some examples, my ackies seem to struggle if it's even just a little bigger than their heads, like when I offer a f/t fuzzie mouse that's a little larger than I wanted to give them, or my rudicollis who did take a rather large "small" rat, but seems to much prefer something in the range of a small to medium mouse. I do seem to remember my savs being able to take proportionally larger prey, but not by a whole lot, but that's also been many years ago, so the memory is a bit fuzzy. On the other side of this are my ball pythons, who may have a body 2 or 3" in diameter, and a head the rough size of a large grape, but even with a head that's maybe an inch in diameter at most, they still manage to suck down a prey item 2, 3, or even 4" in diameter.
    Now something else that occurred to me on this general topic. Snakes, and I'm thinking more in terms of the larger pythons and boas here since thats what I have the most experience with, tend to have a slower metabolism, and often are something of a "lie in wait" predator, so being able to take advantage of a wider variety of prey that happens to wander by would help them to avoid missing a meal. Where as lizards seem to generally have a higher metabolism, an so need to eat more often anyway. And since they actually go out and get their prey, they can look for something more to their liking, rather than having to take whatever happens across their path.
    By the way, love this topkc so thanks to the OP for starting it. I love learning new stuff, even if it's only to take time and explain myself better, since I know someone will call me on it if I don't. And thanks for that Stephan, it really is appreciated.
  8. murrindindi

    murrindindi Elite Member

    There are a couple of articles on the skull and it`s flexibility, not sure if they`re available to read online, but I`ll put the titles up later if anyone`s interested.
    V. acanthurus have a relatively short neck compared to many other Varanid species, I expect that might have at least a bearing on prey size, though they too have the other adaptations.
    I may also have saved a few V. komodoensis videos showing them consuming large portions (whole hindquarters of goats), maybe you`ve seen those already?

    I`m not sure if it shows them actually swallowing large portions in this one but it`s still an interesting video. Note that "Megalania" is now properly described as Varanus priscus, very closely related to komodoensis and V. varius (Lace monitor)/others.
    Last edited: Dec 22, 2014
  9. CTU2fan

    CTU2fan Elite Member

    I knew Megalania was labeled a monitor, I didn't know it'd been reclassified into Varanus though.

    Interesting about the neck, my savannah seemed less comfortable taking really large prey than say a water or dumerilii, with their longer necks. We've all seen that I'm sure, how they "S" the neck swallowing bigger prey.
  10. murrindindi

    murrindindi Elite Member

    "Megalania" has been known to be a Varanid for some time, it`s only the species name that changed to clarify it`s taxonomic position (it was formally known as megalania/V. prisca), now priscus.
    Your Savannah monitor has the same number of neck vertebrae as all other Varanid species (9), the "S bend" is purely to help push the prey down the throat, and they are quite capable of taking relatively large prey.
  11. arojas7112

    arojas7112 Established Member

    "tend to have a slower metabolism, and often are something of a "lie in wait" predator, so being able to take advantage of a wider variety of prey that happens to wander by would help them to avoid missing a meal. Where as lizards seem to generally have a higher metabolism, an so need to eat more often anyway. And since they actually go out and get their prey, they can look for something more to their liking, rather than having to take whatever happens across their path."
    I believed you nailed it right here Darkbird. Any living organism tries to preserve its energy right? The less energy you use, the more you'll have. Animals must gain more energy from their food than they expend in searching for it, capturing it, and consuming it. This energy contributes to movement (hunting, running, digesting, mating, breathing), addition to body mass and overall strength. Snakes in the wild follow this theory by saving energy. If a large snake spends much more energy chasing its prey and catches a small mouse which in turn gives it little to no energy nor protein, the snake will become weaker for its next attempt to hunt. Varanus species having a high metabolic rate, have 2 heart valves (someone call me out if I'm wrong) allowing them to run and breathe faster than other lizard species. They also live by the theory of using less energy, but having physical advances can consume various smaller prey and equal out the energy they spend hunting and consuming. Thus, it becomes critical to take into consideration issues as food choice (size).
    Last edited: Dec 23, 2014

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