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RE: Metabolism of the Crotalinae.
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by theemojohnm on October 30, 2008
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Thanks for your thoughts Fred!
I was wondering where the h*ll you'd been!, and this particular topic seemed right up your alley. I admire your approach to topics such as this, in that you think very "scientific". Aside JohnZ, you are the person I most like getting into the scientific debates with. Actually, besides myself, John, and you (and a few others you know whwere) seem to be the only ones interested in such topics these days. Sure is a shame.
Anyways guys. I do not have a lab, noe the knowledge to use many of the new cutting-edge techniques if I did, but I think I can study this in a controlled way. I plan on getting strikes of pre-killed prey items that both strongly neurotoxic elapids eat, and strongly hemotoxic vipers use. By disecting the mice, I think I can at least get an idea on whether they are actually envenomated, if hemotoxic venoms do "digest".
I would test both specimens using the prey items they naturally eat, aswell as offer them both th other natural food items. I then feel I can get an idea of how fast each animal processes this food by marking defecation intervals, and how long the buldge of the prey item in the stomaches goes down.
I will do this at various temperatures. Of course, there are some other controls to be considered, like weight of the prey item, etc, but I will consider those when I get there. LOL... I like the idea, if nobody minds, of using statements, personal observations, and even just opinions from all of you in a report of my findings once I am finished.
I would actually like anyone to send me (via email) their opinions of why my hypothesis DOES NOT MATCH in many cases. I would even like an argumentive opinion to try and "tear apart" this theory all together. Then, I can see if I can find anything, by close observation, with my limited resources that may help to support, or sugest against anyones opinions on this matter.
Take Care.
~John Mendrola.
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RE: Metabolism of the Crotalinae.
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by puffadder7 on October 30, 2008
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back to the elapids, you were wondering why most elapids dont have hemotoxins and the most crotalinae dont have neurotoxins well if you think about it if most elapids had a hemotoxin along with there extemely high metabolism they would be burning energy so fast they would have to eat every day, but since most elapids have a neurotoxin it takes longer for the prey to break down, there for the neurotoxin will not break the prey down faster, anyone can correct me if im wrong, arin
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RE: Metabolism of the Crotalinae.
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by Cro on October 30, 2008
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I think what we are going to find out, is that there is not going to be a nice / neat conclusion that will answer all of these questions.
We are talking about snakes that live in different habitats, and in different continents, and in different enviornments, and who eat different foods.
Snake venoms have been evolving for hundreds of thousands of years, and continue to do so.
If we narrow down the animals that are being looked into, it is likely that we will find significant scientific data that might show some interesting evolutionary differences in venoms, in Specific populations, and some cool relationships. Also, there will probably be other populations that just do not add up at all.
The good thing in all of this, is that we will in the process of investigation, learn things that were not known about venomous snakes, and we will find relationships that were not known to science, also.
It was only a few years ago that Dr. Bryan Fry found out that many "harmless" Colubrids and Lizards had venom producing glands. Hundreds of thousands of these animals had been disected by taxonomists over the last 150 years, and None of those folks ever bothered to notice the venom producing glands.
I am very impressed when I see folks here develope interesting ideas about venomous reptiles, and put those ideas up for group discussions. Some of the answers and ideas that folks have are very, very interesting.
Best Regards John Z
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RE: Metabolism of the Crotalinae.
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by theemojohnm on October 30, 2008
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Arin, That is in a sense my hypothesis, but completely backwards. I am speculating that the reason many elpaids 9with higher metablic rates) DO NOT use a "tissue destroying, heotxic venom" because somewhere along the line, the evolutionary chain split. Snakes as they evolved, naturally started to expand, inhabbiting different parts of the world.
In warmer climates, other reptiles and amphibians were more predominant and more readily avaliable as prey items, so they needed more rapid systematic "stopping power", thus, elapids developed a fast-acting neurotoxic venom. But, there was a problem in that nerotoxic venom seemingly does very little for the breaking down of tissue (again, this doesnt fit in every case), this naturally left elapids more active with higher metabloic rates.
Whereas the snakes that found their way to the US and colder climates around the world adapted very nasty hemotoxic, tissue destroting compunds to their venoms, which also helped to digest their prey because heat wasnt as annually avaliable, or as intense as to those elapids found in warmer climates. Because of less heat, alot of vipers take longer to metabolize food, and spend more time absorbing heat. So, the hemotoxic components in their venoms helped if they needed the extra digestion help.
I do not believe that hemotoxic snakes envemate every time they eat, only when they need to. In captivity, it makes sense that alot of times hemtoxic snbakes do not envenomate food if they can tell it is dead, because, in captivity, temperatures are ussualy a little higher and more consisitant than they would be in the wild.
Take Care.
~John Mendrola.
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RE: Metabolism of the Crotalinae.
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by theemojohnm on October 30, 2008
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Actually, this hypothesis may not even be too relevant any more. Maybe this is the way things developed when theese animals were in the beginning stages of venom evolution.
This would explain some of the "exceptions" I discussed. perhaps over the course of a fe hundred years, rodents have become more abundant in the habitat of Naja kaouthia, and this is why they have developed a flesh-destroying component to their venoms, to better immobilize warm-blooded prey, but still retain strong neurotoxic components becasuse lizards and frogs are still readily avaliable.
John brought up Naja kaouthi in another thred, so I just thought I'd use that as an example. There are many exceptions, and some are not so clear as to what factors may be causing the change in venom. Again, this is only my hypothesis, but I really enjoy discussing the topic with you all!
Thanks to everyone for your input!
~John Mendrola.
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RE: Metabolism of the Crotalinae.
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by Crotalusssp on October 30, 2008
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I agree with JohnZ. We are talking about hundreds of thousands of years of evolution. There will not be 1 theory that will work across the board. Each family solved problems in different ways. Then as natural selection continued from there the different genus each changed to fit their niche,followed by individual species. There is more than one way to solve a problem, when speaking in terms of evolution. That is the beauty of natural selection and evolution. Different paths can lead to completely different answers to a problem, or sometimes, in cases such as convergent evolution, two different paths can come together to answer questions in very similar methods.
Charles
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RE: Metabolism of the Crotalinae.
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by theemojohnm on October 30, 2008
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Charles, you are correct, and I agree.
This would explain constrictors of course, and all of the exceptions to this hypothesis. (neurotoxic vipers, sea snakes, and elapids with necrotic venom components).
I just think that geographic region, climate, and food force, were probably ONE of a number of factors that are responsible for this difference in metabolism and venom composition, although I think this may have been a VERY BIG one, and seemingly still may be today. Evolution is still at work every day, and many possible solutions to environmental problems are solve differently.
Some of the new venom findings should prove to get better over the next few years, and hopefuylly the answers to some of these questions will be solved, or at least, give us a better idea of how and why this is. Mojave rattlesnake venom is interesting too. The differences in the venom makeup here are hard for me to believe this is accidental.
These snakes have eveolved many different routes for combating environmental problems. This is only ONE of the POSSIBLE explanations that generally does seem to fit in alot of cases. Whether this is factually from the reasons in my hypothesis, we yet do not know. It just seems like for many cases, this does have some genral reason, although it may not be according to the factors I stated in my post.
I am anxious to hopefully see some further answers in my lifetime!
Take Care.
~John Mendrola.
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