Reptile & Amphibian Forums

I have read your report on colubreds being venomous, and frankly im more than a little nervose. I keep a corn snake, sinaloan milk snake and green snake plus a red tail boa. dose this mean my corn snake could KILL me? I also do snake removal so dose this mean I sould use my tongs and snake hooks on snakes like Elaphe obsoleta? I live in north carolina is there any dagerusly venous coubreds where I live. what precasuns sould I take whith my PET snakes now. PLEADE HELP ME OUT. Do I need to treat coulubreds like I treat Vipers that I remove frome peaples house.
PS. sorry about any spelling probs

A very worrid Randy
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1.0.0 albino okeetee corn
0.1.0 red tail boa
0.1.0 sinoalon milk snake
0.0.1 green snake
0.0.1 green igauna

Yep...see, this is exactly the sort of reaction I was concerned about.

Randy,
I don't think that you have anything to worry about any more than the hundreds of thousands of people that have been bitten by North American Rat Snakes over the past 10,000 years. Maybe if you let one bite you and chew for 15 minutes or so you would get enough Colubritoxin to cause a very mild reaction, but I doubt it. From what Bryan was saying, one of the European Rat Snakes (2 meters long) they tested was essentially milked dry by anesthetizing it, then administering a drug that causes it to salivate freely. The most Colubritoxin they could get out of it was not enough to be dangerous to a human. That does not take into account the rare individual that may be hypersensitive to the components in the saliva (including Colubritoxin) and may suffer some allergic reaction.

Bottom line...if a Corn Snake wasn't dangerous yesterday, it's probably not dangerous today. Maybe it will be more dangerous in a few hundred years, maybe not. That's one of the values of the study. It will be useful in studying the past evolution of Colubroid snakes and predicting future evolution, plus there are some pretty far ranging implications with Biomedical research. I don't think the study was intended to cause a panic over Rat Snakes and the data doesn't suggest that that is warranted.

In a discussion (actually raging arguement) on the taxonomy thread, Dr. Fry said:

The fatal flaw with your scenario is that it assumes that Coelognathus post-dates the evolution of the American Lampropeltis/Patherophis/Pituophis lineage when in fact all the American colubrines are descended from Asian invaders. Thus, mapping over the taxonomical tree shows that venom evolved a single time, was lost in the American lineage and then thats it

So american rat, king & gopher snakes have no venom.

>>So american rat, king & gopher snakes have no venom.

Hi mate

The evidence is certainly leaning that way. We have a few things we'd like to do to absolutely confirm it but at this stage it seems that the most likely answer will be that they don't

Cheers
B
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Dr. Bryan Grieg Fry
Deputy Director
Australian Venom Research Unit
University of Melbourne

www.venomdoc.com

Bees are venomous. But a honey bee sting will not kill you. Actually, true honey bee stings barely hurt. If a report came out saying that honey bees happen to have a toxin in their venom in low concentrations that resembles funnel web spider venom, that wouldn't make honey bees any more dangerous than they are today.
The tarantula keeping hobby is based around a group of animals that are ALL venomous, but everyone understands that for the most part they aren't dangerous.
To sum up, the only way a cornsnake, or for that matter, Coelognathus could kill you is if you were trying to eat one and choked on it.
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Peter: It's OK, I'll handle it. I read a book about something like this.
Brian: Are you sure it was a book? Are you sure it wasn't NOTHING?

"Bees are venomous. But a honey bee sting will not kill you. Actually, true honey bee stings barely hurt. If a report came out saying that honey bees happen to have a toxin in their venom in low concentrations that resembles funnel web spider venom, that wouldn't make honey bees any more dangerous than they are today."

Actually bees can kill. More people in the US die of bee stings and insect bites than snake bites each year and those statistics were compiled before the Africanized or "killer" bees made it north from the Neotropics.

"The tarantula keeping hobby is based around a group of animals that are ALL venomous, but everyone understands that for the most part they aren't dangerous. To sum up, the only way a cornsnake, or for that matter, Coelognathus could kill you is if you were trying to eat one and choked on it."

Tarantulas are mildly venomous, and they are very gentle animals. That makes them relatively safe. A cornsnake can potentially kill if one is allergic to its saliva, just as horse antivenin can potentially kill if one is allergic to horses. That said, Dr. Fry and his colleagues are dead wrong in claiming that all colubrids are venomous. Their conclusion is based on a leap of faith. It is not a sound scientific conclusion and it is therefore extremely controversial and not widely accepted among scientists. Dr. Fry is actively promoting his claim using the popular press and Internet discussion forums. The uninitiated have apparently been alarmed by his claim, but the scientists know better. The truth is that only a few colubrids are dangerously toxic and even fewer of them use their Duvernoy's gland secretions as venom (to kill prey). Many people who die from the bites of non-venomous colubrid snakes had prolonged exposure to the secretions (one victim for example allowed the snake to chew on his finger for over two minutes) and many victims die days or even weeks after the bite, suggesting that allergic reaction or similar clinical complications, rather than toxic effects from the neurotoxic components of the secretions, is what really killed them.

> Many people who die from the bites of non-venomous colubrid

I rest my case.

Cheers,

Wolfgang
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WW Home

With the exception of allergies. Peanut allergies kill a lot of people too.
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"The serpent crams itself with animal life that is often warm and vibrant, to prolong an existence in which we detect no joy and no emotion. It reveals the depth to which evolution can sink when it takes the downward path and strips animals to the irreducible minimum able to perpetuate a predatory life in its naked horror."
Alexander Skutch

Certainly there are people who die from bee stings because of allergy, but bee venom can kill if a large enough number of bees sting a human victim.

In a review paper titled "COLUBRID ENVENOMATIONS IN THE UNITED STATES" David Chiszar and Hobart M. Smith (2002, J. TOXICOL.—TOXIN REVIEWS, 21(1&2), 85–104) concluded that "...many so-called [colubrid] envenomations might actually be allergic reactions...."

WW and his colleague Dr. Fry of course do not accept Chiszar and Smith's conclusion because they have made up their mind that all colubrid snakes are the descendants of a venomous ancestor and therefore all human victims of colubrid snake bites are the result of envenomization. WW and Dr. Fry are using the medical definition of venom, a definition that would have considered human saliva venom and human beings venomous animals. A more rigorous definition of venom takes into account not only the toxicity of a secretion but also its biological role. A toxic substance must be used primarily as a means for causing rapid prey death or for defense purposes before it can be classified as venom (Kardong 2002, J. Toxicol. Toxin Rev.). Other biologists, especially those who are more objective than WW and Dr. Fry, are more likely to adhere to the biological definition of venom outlined in Dr. Kardong's paper than the medical definition that Dr. Fry and WW have embraced.

Perhaps you could explain how a neurotoxin can be used for digestion or how bleeding out of every orifice could be the result of allergy?

Keep sailing your ship towards the edge of the world, maybe we'll all get lucky and it might actually fall off.

Dr. Fry wrote:
"Perhaps you could explain how a neurotoxin can be used for digestion or how bleeding out of every orifice could be the result of allergy?"

Dr. Kardong writes:
"Toxicity is clearly an incidental byproduct of human saliva, not an indication of biological role."

Me:
Neurotoxicity of some molecules which may have evolved originally to serve other functions in the snake's body can also be a byproduct, not an indication of their biological roles. Similarly, carbon dioxide and ammonia are toxic, but clearly these compounds are byproducts of metabolism and their toxicity are also byproducts, not indications of their biological roles. We simply do not know the original function of some of the toxic molecules found in snake venom; such knowledge requires further investigation. Asserting that they originally evolved as venom because they are toxic amounts to a leap of faith.

Okumura et al. (2002), fortunately, do not leap to the conclusion that the presence of PLA2 in Elaphe quadrivirgata is evidence that this compound originally evolved to serve as venom. Instead, they conclude:

'Since PLA2-rich tissues, such as the venom glands of venomous snakes, are not present in the nonvenomous E. quadrivirgata, purification of endogenous PLA2 from E. quadrivirgata becomes very difficult. To elucidate the physiological function of PLIbeta in E. quadrivirgata, we are making an effort to identify and characterize the endogenous PLA2 from the lung tissue of this snake.'

Fortunately not all scientists leap to conclusions. Not all scientists conclude that toxic molecules found in the secretions of snakes are automatically classifiable as venom. The original function of the neurotoxic molecules found in snake venom awaits investigation. Isolating them from nonvenomous colubrid snakes and identifying their chemical structures are necessary first steps, but these preliminary findings by no means tell us anything about their origin or original function, notwithstanding your leap of faith that they originally evolved as venom.

>>"Toxicity is clearly an incidental byproduct of human saliva, not an indication of biological role."

Thats due to infection, not due to interference with crucial biological processes. There is a remarkable difference and that is the same smelly red herring you love to trot out.

>>
>>Me:
>>Neurotoxicity of some molecules which may have evolved originally to serve other functions in the snake's body can also be a byproduct, not an indication of their biological roles. Similarly, carbon dioxide and ammonia are toxic, but clearly these compounds are byproducts of metabolism and their toxicity are also byproducts, not indications of their biological roles. We simply do not know the original function of some of the toxic molecules found in snake venom; such knowledge requires further investigation. Asserting that they originally evolved as venom because they are toxic amounts to a leap of faith.
>>
>>Okumura et al. (2002), fortunately, do not leap to the conclusion that the presence of PLA2 in Elaphe quadrivirgata is evidence that this compound originally evolved to serve as venom. Instead, they conclude:
>>

Thats because they isolated a PLA2-inhibitor.

>>Fortunately not all scientists leap to conclusions. Not all scientists conclude that toxic molecules found in the secretions of snakes are automatically classifiable as venom.

Thats because they have not isolated them or assayed the biological effects as we have. That is the difference.

Dr. Fry wrote:
"[Toxicity of human saliva is] due to infection, not due to interference with crucial biological processes. There is a remarkable difference and that is the same smelly red herring you love to trot out."

Me:
Are you claiming that it is the bacteria or other microbial agents in saliva that is causing the toxicity? If so, I would love to see a reference that suggests that.

Me:
'Okumura et al. (2002), fortunately, do not leap to the conclusion that the presence of PLA2 in Elaphe quadrivirgata is evidence that this compound originally evolved to serve as venom.'

Dr. Fry:
"Thats because they isolated a PLA2-inhibitor."

Me:
In their paper, they also said that they confirmed the presence of PLA2 in the lung and liver of Elaphe quadrivirgata. The PLIbeta is there to inhibit the activity of the PLA2 and/or to neutralize the toxic effects of the PLA2 found inside the snake's body. What is PLA2, which is a key component of viperid venom, doing in a non-venomous colubrid snake? That is the question Okumura et al. are attempting to answer. They do not, unlike Fry et al., assume that because PLA2 is a toxic molecule, it must have originally evolved as venom, that it evolved in the common ancestor of the viperids and colubrids, and that it is thus evidence of the early evolution of venom.

Me:
Fortunately not all scientists leap to conclusions. Not all scientists conclude that toxic molecules found in the secretions of snakes are automatically classifiable as venom."

Dr. Fry:
"Thats because they have not isolated them or assayed the biological effects as we have. That is the difference."

Me:
Fry et al. have not attempted to investigate the possible original function of the toxic molecules found in colubrid snakes. Okumura et al. are attempting to answer that question. Fry et al. have made up their mind that venom evolved early because they are relying on the medical definition of venom, namely "if it is toxic, then it is a venom" (Kardong 2002). Okumura are not using that overly broad definition of venom. That is the real difference.

Reference

Kardong, K. 2002. COLUBRID SNAKES AND DUVERNOY’S "VENOM" GLANDS. J. TOXICOL.—TOXIN REVIEWS, 21(1&2), 1–19

CK,

Before I type anything further, I'd like to stress that I want to avoid any circular debates with you such as those you've been forcing upon others here. That being said, I would like to address your following statements:

Dr. Fry wrote:
"[Toxicity of human saliva is] due to infection, not due to interference with crucial biological processes. There is a remarkable difference and that is the same smelly red herring you love to trot out."

Me (CKing):
Are you claiming that it is the bacteria or other microbial agents in saliva that is causing the toxicity? If so, I would love to see a reference that suggests that.

I'm a little unclear about what specifically you (or Kardong?) are calling "toxicity" with respect to human saliva. Systemic effects consistent with envenomation are not known following bites by humans (which, by the way, is not an uncommon occurrence! See Holyfield ). Therefore, I'm going to assume you are referring to local inflammatory effects such as redness, pain, and swelling. These are almost certainly secondary to oral bacteria introduced into the wound during a bite. Several bacteria are known to colonize human mouths, and these have been routinely cultured from infected human bite wounds (Talan, et al.). The presence of bacteria in human tissue triggers an innate immune response, including release of inflammatory mediators by cells like dendritic cells, macrophages, and neutrophils which have receptors for bacterial components like lipopolysacharide and peptidoglycan, as well as bacterial DNA (for a review if adaptive and innate immune mechanisms see Dempsy, et al.). Again, when cells bearing these receptors encounter bacterial products, they become activated and release inflammatory mediators which, in turn, bring about redness, swelling, and pain often seen / encountered at sites of human saliva introduction. Conversely, nothing of human origin contained in human saliva is known to produce this type of inflammatory response in human tissue (see Humphrey).

I hope this clarifies somewhat why human saliva is a poor argumentative tool in the context of this discussion. It is indeed, as BGF stated earlier, a "red herring".

Cheers,
WK

References:

Dempsey, PW et al. THE ART OF WAR: Innate and adaptive immune responses. Cellular and Molecular Life Sciences. 2003 Dec; 60(12): 2604-21.

Holyfield, E. That M%&&$F#@#&R bit my ear off! Complaint to referee in reference to M. Tyson. World Heavyweight Boxing Chamionship Match. 1997 Jun 28 Pay Per Chew Television.

Humphrey, S. A review of saliva: Normal composition, flow, and function. The Journal of Prosthetic Dentistry, Volume 85, Issue 2, Pages 162 ¡V 169.

Talan, DA et al. Clinical presentation and bacteriologic analysis of infected human bites in patients presenting to emergency departments. Clinical Infectious Diseases. 2003 Dec 1; 37(11): 1481-9.

Hi mate

Don't fret, the ratsnakes for example are no more dangerous today than they were thought of a week ago. In another one of our papers (the LC/MS one you can download from the publications section of my webpage) we quite clearly state that for many commonly kept species, the full envelop of potential reactions are known (eg 10s of thousand of people have safely kept garter snakes, with only a low incidence of largely localised reactions to the venoms (swelling, itchiness, a bit of bleeding) and only one well documented case of neurotoxicity following a garter snake bite (to a small child that somehow was chewed on by a big bloody garter snake for quite a long time). These snakes are putting out the same venom as cobras/death adders but for many it is in very small quantities. For the ratsnakes, think of them as serving full-strength beer in a thimble. Other lineages, however, put out considerably more venom (Psammophis and Telescopus species for example have massive venom glands). With new colubrids that become available, a bit of sensible caution would be a logical move.

Cheers
Bryan
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Dr. Bryan Grieg Fry
Deputy Director
Australian Venom Research Unit
University of Melbourne

www.venomdoc.com

>>For the ratsnakes, think of them as serving full-strength beer in a thimble.>>
You're talking about the old world ratsnakes, right? From your posts in the taxonomy forum, I gathered that your opinion is that the american ratsnakes and the other Lampropeltini have lost all of their venow producing capabilities.

>>>>For the ratsnakes, think of them as serving full-strength beer in a thimble.>>
>>You're talking about the old world ratsnakes, right? From your posts in the taxonomy forum, I gathered that your opinion is that the american ratsnakes and the other Lampropeltini have lost all of their venow producing capabilities.

HI mate
There is some histiological evidence that the venom glands have switched most if not all of the protein secreting cells into mucous producing cells. For the individual cells its largely a case of one or the other. We are going to have a close look at them this year to tidy this area up.

Cheers
Bryan
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Dr. Bryan Grieg Fry
Deputy Director
Australian Venom Research Unit
University of Melbourne

www.venomdoc.com

I was wondering if the North American racers have a toxic saliva? I notice that when a ratsnake eats it's prey they wrap it up and constrict, but every time I have seen a racer eat its prey they just bite and swallow. It also seems that once the racers have bitten their prey it becomes almost paralyzed. Is this because they have a small amount of venom? I am not worried at all by any of the colubrids in North America but I am just curious.

Thanks,

Jeremy
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1.1 C. cerastes
1.0 Ball python
0.1 Columbian red tail
0.1 Argentine boa
0.1 Dumerils boa
0.0.1 Albino bannana cal king
1.1.3 Leopard geckos
1 Male albino
1 Female het albino, blizzard, jungle
1 ? albino
1 ? patternless
1 ? not normal but I dont know what it is
0.0.3 Rough skin newts
0.0.1 Whites tree frog

>>I was wondering if the North American racers have a toxic saliva? I notice that when a ratsnake eats it's prey they wrap it up and constrict, but every time I have seen a racer eat its prey they just bite and swallow. It also seems that once the racers have bitten their prey it becomes almost paralyzed. Is this because they have a small amount of venom? I am not worried at all by any of the colubrids in North America but I am just curious.

This is from http://bio.bd.psu.edu/dmm/snake/snake.htm

Parrish, H. M. 1980. Poisonous Snakebites in the United States. Vantage Press, New York, NY, 469 pp. Relates (from reprint Parrish et al., 1973, Southern Medical Journal) localized effects native Natrix, Coluber bites to volunteers - slight pain, oozing blood (longer than expected), itching and tingling less commonly.

I vaguely recall reading elsewhere that they seem to subdue their prey with remarkable rapidity with what appears to be venom.

Cheers,

Wolfgang
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WW Home

/

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1.1 C. cerastes
1.0 Ball python
0.1 Columbian red tail
0.1 Argentine boa
0.1 Dumerils boa
0.0.1 Albino bannana cal king
1.1.3 Leopard geckos
1 Male albino
1 Female het albino, blizzard, jungle
1 ? albino
1 ? patternless
1 ? not normal but I dont know what it is
0.0.3 Rough skin newts
0.0.1 Whites tree frog

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Edited on January 12, 2004 at 18:58:17 by PHWyvern.