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filthy
SFN Die Hard
USA
14408 Posts |
 Posted - 04/13/2005 : 06:32:50
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A couple of days ago, Dr. Mabuse mentioned that he wanted to ask me about the evolution of these in the chat room. I'd missed that chat, foir various, bullshit reasons, so I'm posting a sort of hit-the-high-spots in it's place. It's far too big a topic for a chatroom, anyway.
So, with no further ado, come visit my world....
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Question: “Which came first, the chicken or the egg?”
Answer: “Who cares; pass the Tabasco.....”
A similar and equally idiotic question/statement has been snidely put forth about serpent venoms, and it's rather like the ‘half-wing' straw man blather-from-ignorance we hear from various Creationist groups: “Of what use is venom with no injection system, and vise-versa?”
Answer: “Obviously none, therefore it all had to be created at the same time, proving the Theory of Evolution is false, and ha-ha all over you!”
In this screed, I will pass the Tabasco.
First, what exactly is a venom? What makes an animal ‘hot, ' and how is this any different from a poison. We'll quickly straighten the latter out first: basically, venoms are injected; poisons are ingested.
A venom is any substance produced and used by an animal to subdue prey and/or defend itself. The list of venomous animals is an extensive one and it goes far beyond snakes. There are hot insects and arachnids, as we all know, and even a few mammals such as shrews. A stab from the venomous spurs of a male platypus and it's fellow monotreme, the echidna, can be a quite painful experience. There are even venomous birds. A great many sea creatures are venomous, including but not restricted to jellyfish, anemones, corals, octopi, and some fish such as stingrays, stonefish and the gafftops'l catfish have venomous spines. These incidentally, fit nicely in the skillet, venom not withstanding.
I once met a man who claimed to have been stung by a cone shell, species unknown (the shell that is, not the man). He found it in shallow water, and as it was pretty, he took it to his hotel room and began digging at it with a jack knife; to kill it, one presumes. The gastropod reacted predictably and stabbed him in the finger with one of it's ‘harpoons.' He told me that he has never experienced such pain, before or since.
I can personally attest to the effectiveness of sea wasp and Portuguese man 'o war venoms.
So, considering the minute amounts of venom injected, various sea creatures are the hottest in the world.
But back to the question of the evolution of venoms and their injection systems in serpents. As I have stated elsewhere, venom evolved first, and exactly how it happened can be easily seen in living Colubrid species today. All snakes have duvernoy's organs, the venom glands, although they are degenerate in constrictors such as the Boids (boas and pythons), that don‘t rely as much on biting to subdue prey. These are modified salivary glands that are used to produce a saliva of varying degrees of toxicity. It shows up in that the bites of many non-venomous snakes are messy far past the severity of the bite, which seldom amounts to more than a few pinpricks. It is considered an anticoagulant, but it is a little more than that in that it contains toxins that will slow down a frog, or in the case of small snakes such as ringnecks and dekay‘s, large earthworms and slugs, and render them more manageable. None of these are medically significant to humans and, having no fangs, these snakes must chew vigorously to inject the, well, saliva (can‘t quite bring myself to call it a venom).
But as we p
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist! 
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bloody_peasant
Skeptic Friend
USA
139 Posts |
 Posted - 04/13/2005 : 07:43:48 [Permalink]
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Great stuff filthy. Its really interesting how the venom glands are modified saliva glands. Sorta like how primitive eye spots are just modified nerve cells. More evidence of how evolution works with what its got and doesn't invent complete systems from scratch. Also great description of the different delivery systems, I wasn't aware of quite a few of those.
So it would probably be safe to say that the ancestors of the first venomous snakes had saliva glands and teeth of some sort (not a big stretch there). Eventually the right mutation would produce a slightly toxic saliva to help subdue their prey offering an immediate advantage. The delivery would be similar to that of the Colubrid's and would consist of just gnawing to break the skin and stimulate the saliva glands and letting the toxins ooze into its prey. Once this basic system was in place any modification to the delivery system could easily happen in stepwise improvements.
I've seen a nonvenomous brown water snake consume a small bull frog. Its amazing how long the process takes and the frog lives for quite some time as the snake slowly engulfs the whole thing. Eventually the frog is subdued probably due to suffocation I would guess. Its also pretty easy to see the advantage a venomous system offers beyond mere self-defense. Being able to subdue your prey quicker would reduce risk of injury from the struggling animal (especially with clawed vermin like rats). Also the snake appears to be quite exposed to predators while in the process of getting his meal down. A struggling and possibly squealing animal would also draw unwanted attention. The venom would allow the snake to consume his meal quicker and quieter. Obvious advantages. |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 04/13/2005 : 09:57:15 [Permalink]
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quote:
Originally posted by bloody_peasant
Great stuff filthy. Its really interesting how the venom glands are modified saliva glands. Sorta like how primitive eye spots are just modified nerve cells. More evidence of how evolution works with what its got and doesn't invent complete systems from scratch. Also great description of the different delivery systems, I wasn't aware of quite a few of those.
So it would probably be safe to say that the ancestors of the first venomous snakes had saliva glands and teeth of some sort (not a big stretch there). Eventually the right mutation would produce a slightly toxic saliva to help subdue their prey offering an immediate advantage. The delivery would be similar to that of the Colubrid's and would consist of just gnawing to break the skin and stimulate the saliva glands and letting the toxins ooze into its prey. Once this basic system was in place any modification to the delivery system could easily happen in stepwise improvements.
I've seen a nonvenomous brown water snake consume a small bull frog. Its amazing how long the process takes and the frog lives for quite some time as the snake slowly engulfs the whole thing. Eventually the frog is subdued probably due to suffocation I would guess. Its also pretty easy to see the advantage a venomous system offers beyond mere self-defense. Being able to subdue your prey quicker would reduce risk of injury from the struggling animal (especially with clawed vermin like rats). Also the snake appears to be quite exposed to predators while in the process of getting his meal down. A struggling and possibly squealing animal would also draw unwanted attention. The venom would allow the snake to consume his meal quicker and quieter. Obvious advantages.
Very much so. One mystery is that more animals don't use venom. There is no way to verify it, but one suspects that incapacating forms of saliva, even venoms, were commonly used way back in the dino ages. Perhaps eariler; the Late Devonian, maybe, or even earlier. It's just such an efficent tool, and the basic, necessary parts already being in place, the evolution would seem to be a natural.
I once observed a southern watersnake (Nerodia fasciata) eat a catfish, I ask you to believe! That was a slow process and for a while, I was wondering which was going to finally kill the other. |
"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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| Edited by - filthy on 04/13/2005 10:15:46 |
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bloody_peasant
Skeptic Friend
USA
139 Posts |
Posted - 04/13/2005 : 10:49:25 [Permalink]
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quote:
I once observed a southern watersnake (Nerodia fasciata) eat a catfish, I ask you to believe! That was a slow process and for a while, I was wondering which was going to finally kill the other.
I grew up on a farm and we had about 1 acre pond on it that I stocked with bass I caught from nearby creeks (the same pond where I watched the water snake eat the frog). We had built a small dock on the pond and I was standing on it one spring day when a brown water snake swam by. There were a couple of fairly large large-mouth that often hung out by the dock.
It being spring and fish being aggressive both in defense of their eggs and also in search of food it was a mistake that poor snake probably never wish it made. The bass hit that snake so hard and drug it under (it was probably about a 16" long or so snake and about a 24" or so bass). It kept getting lose and then it would get hit again - boom. A bunch of smaller bass were swarming and hitting the thing too. It looked like a shark frenzy.
Finally a smaller fish hit and pulled it out of the large bass' mouth and the snake managed to escape to the bank. I'm not sure if the snake actually managed to survive as it had innards hanging from its stomach where the fish tore into it.
There's a reason why fake snake lures are sometimes used in the early spring >:-D (don't tell any of your precious friends this story though they might get nightmares >:-D)
quote:
Very much so. One mystery is that more animals don't use venom. There is no way to verify it, but one suspects that incapacating forms of saliva, even venoms, were commonly used way back in the dino ages. Perhaps eariler; the Late Devonian, maybe, or even earlier. It's just such an efficent tool, and the basic, necessary parts already being in place, the evolution would seem to be a natural.
Like most things there are always trade-offs and if you don't make a living killing things with your teeth toxins probably have a form of trade-off WRT to resource usage.
A question I have, is our snakes effected by their own venom if it enters their bloodstream (or for that matter the venom of other species)?
Another question, I wonder what modified systems compose the venom systems of things like the platypus? Possibly musk systems? |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 04/13/2005 : 11:43:14 [Permalink]
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quote:
A question I have, is our snakes effected by their own venom if it enters their bloodstream (or for that matter the venom of other species)?
Another question, I wonder what modified systems compose the venom systems of things like the platypus? Possibly musk systems?
Depends.... And ain't that a shitty answer? 
A snake will not be killed by the venom of it's own species, as far as I know (there are a lot of species out there). However, venoms from other species can quickly be fatal. King cobras, for example prey solely upon other snakes, including cobras, karaits, and so forth. The American kingsnakes, constrictors, are resistant to the venom of rattlesnakes within their range, but would succumb to a bite from one of the durissius complex of rattlers of South and Central America, which carry an altogether different mix of venoms.
Interesting kingsnake fact: they can comfortably swallow another snake almost twice their own length. They swallow it head first and will actually fold it double in their stomachs.
As for the platypus, at last reading, the current thought was that, as only the males have spurs, they are somehow used in courtship fights and perhaps defending a mate. Unfortunatly, these animals are even more shy than snakes, and there is a great deal yet to be learned about them.
Waternakes and turtles are some of the most valuable species that you can have in a small pond. They weed out sick and dead fish and, other organisms, and as you have noted, they provide some food for the rest of the pond's inhabitants. The turtles, especally snappers, also keep the bottom of the pond aeriated with their digging and scratching around.
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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bloody_peasant
Skeptic Friend
USA
139 Posts |
Posted - 04/13/2005 : 12:14:48 [Permalink]
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Figures >:-D Is that true even if the snake gets bitten by another of its own species? I was reading your venomous shrew article and it indicated that it was practically immune if it ingested its venom, but that was due to the toxin proteins being too large to be absorbed through the mouth and stomach acids destroying them. However they speculated they wuold be effected if the venom was injected say via a bite.
Yeah we had quite a few snappers in there too. I assume we still do ;) not to mention a whole myriad of insects and the sort. We also put some catfish in there to help aeriate the bottom as well and some grass carp to help keep the vegetation down to a manageable level. The dang weeds and algae was causing the water to turn anaerobic :<.
I actually caught a snapper once fishing in a creek for catfish. My friend started making fun of me cause he thought I had snagged a log or something and I would have to re-tie everything when it suddenly started moving slowly towards me as I pulled. It didn't jerk or fight and really felt like a log or heavy branch that was slowly being pulled to the bank. Suddenly it walked up on the bank hissing like a banshee. I simply cut my line and re-tied as I valued my fingers >:-D |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 04/13/2005 : 13:51:40 [Permalink]
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quote:
Originally posted by bloody_peasant
Figures >:-D Is that true even if the snake gets bitten by another of its own species? I was reading your venomous shrew article and it indicated that it was practically immune if it ingested its venom, but that was due to the toxin proteins being too large to be absorbed through the mouth and stomach acids destroying them. However they speculated they wuold be effected if the venom was injected say via a bite.
Yeah we had quite a few snappers in there too. I assume we still do ;) not to mention a whole myriad of insects and the sort. We also put some catfish in there to help aeriate the bottom as well and some grass carp to help keep the vegetation down to a manageable level. The dang weeds and algae was causing the water to turn anaerobic :<.
I actually caught a snapper once fishing in a creek for catfish. My friend started making fun of me cause he thought I had snagged a log or something and I would have to re-tie everything when it suddenly started moving slowly towards me as I pulled. It didn't jerk or fight and really felt like a log or heavy branch that was slowly being pulled to the bank. Suddenly it walked up on the bank hissing like a banshee. I simply cut my line and re-tied as I valued my fingers >:-D
Mammals aren't really my bag, but I wouldn't think that they could seriously envenomate each other. My reasoning is that during mating, a fair amount of biting is done, mainly by the male to the female's neck area. There is also the consideration that, as the amounts of saliva are relativly small, very little would pass into tne other's lymph system (venom travels mainly in the lymph). Also, like most if not all mammals, it would lick an injury, putting saliva into the wound.
Further, I think that the saliva/venom is mainly effective only on prey already being eaten, such as insects, arachnids, small lizards and snakes, and so forth. It must be remembered that these sorts of venoms are pretty weak and produced in small quanities. I have never been bitten by a shrew, but I would expect no more than mild, local symptoms, if that. A slight numbness at the site of ther bite, perhaps.
Sounds like a good pond, and you were wise to not mess with that snapper. They really bite, and won't let go 'till it thunders! Well, not quite that long, but they do hang on.
Over the last few years, I have rehabbed 3 of them; 2 hit by cars and one shot by a shithead. All were successful, and all were a handful -- downright dangerous -- to treat. One of the car-hit ones dropped some 20 eggs in her tub, to my delight. Turtle eggs are very tasty. They are about the size of a ping-pong ball, and quite rich.
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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H. Humbert
SFN Die Hard
USA
4574 Posts |
Posted - 04/13/2005 : 14:54:40 [Permalink]
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Awesome post, Filthy. I had no idea there were venomous birds. That's wild.
quote:
Originally posted by filthy
It is difficult to imagine where Viperid evolution might go from here. They are just so damned good at what they do....
I think we can all see the next logical evolutionary step.
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"A man is his own easiest dupe, for what he wishes to be true he generally believes to be true." --Demosthenes
"The first principle is that you must not fool yourself - and you are the easiest person to fool." --Richard P. Feynman
"Face facts with dignity." --found inside a fortune cookie |
| Edited by - H. Humbert on 04/13/2005 14:54:58 |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 04/13/2005 : 15:47:21 [Permalink]
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I have only read about these birds, and there is precious little literature on them to be found. I wonder if the venom is produced by the bird or is aquired from an item in their diets. That sort of thing is not uncommon. For example, some species of nudibranchs attack and eat jellyfish and anomenes, and retain the nematocysts for their own defense. Perhaps the birds have a resistance to certain, poisonous insects or their larvae, and regularly feed on them, retaining the toxins.
Venom and the animals that use it are fascinating...
Heh, edited to add that Squamata has long since evolved far beyond the mere alien. You should see the dentation of of an angry puff adder when you're holding it by it's neck and it's trying to twist enough to get at your thumb -- and you're wondering about how the hell you're gonna let it go....!
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
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| Edited by - filthy on 04/13/2005 15:56:37 |
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