Reptile & Amphibian Forums

I'm sure this is a fairly common thread, but here goes...I was wondering if anyone could point me in the right direction ie journals or papers on whether or not hognose snakes can produce venom. I am an undergrad at Delaware Valley College in Pennsylvania and would like to do a research project to do a quantitative and qualitative analysis of hognose venom. I haven't been able to find too much info and if they actually do produce venom or if their rear fangs or more for aid in killing toads. I was wondering if anyone knew if a project like this has ever been done before or if there were any journal articles published already on it. I plan on using eastern hogs for the project as i live in new jersey and can catch them fairly easy, but if anyone knows a species that might be better, that would be greatly appreciated as well. Thanx in advance for any help you guys can give me!
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1.0 Normal Cornsnake
1.0 Sumatran Short Tail Python

Here is something I came across not too long ago.

http://www.herpnet.net/bite/

Just remember, the guy said he let it chew 3 to 5 minutes! Anyone would have some sort of reaction to being chewed on for that amount of time.
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Jenea

1:1 Tricolor Hognose
0:0:2 Florida Redbelly Snakes
0:1 Gulf Coast Box Turtle
1:1 Red-eared Slider
0:0:1 Green Tree Frog
1:2:2 Mediterranean Geckos
2:0 Cats
1:1 Kids
1:0 Spouse

"Just remember, the guy said he let it chew 3 to 5 minutes! Anyone would have some sort of reaction to being chewed on for that amount of time."

One of my westerns chewed on me for about 5 minutes during a botched feeding. The bite occured on my left hand, in the flesh just below my forefinger. I documented the bite with photographs and written log entries, every five minutes for 45 minutes. Aside from physical damage caused by the teeth and enlarged teeth, i had no reactions. When nothing happened, i discarded the information; either i had not been envenomated, or the venom had no effect on me. I have no way of knowing either way.

Since that time, I remember taking some time to look at the venom papers coming out recently, and thinking that hognose venom is very complex and similar to pit viper venom in scope. I guess delivery is just pretty poor. I have a hard time believing that a snake would not choose to envenomate a potential food item, even if i was bitten in error.
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Erik Williams

fattailed geckos, western hognoses, and a bunch of postage stamps.
Contact me
www.chicagoherp.org
Chicago Herpetological Society

Wow! Interesting topic. The pics from that link were amazing. it makes me look @ my little '05 Western in a new light. Have there been any other similar studies done on the venoms of the other hognose species (easterns? southerns? Mexican?)?

reako45

Try http://www.venomdoc.com Dr. Fry has a forum all about venom research etc.

Hope this helps?

Tom

>>Try http://www.venomdoc.com

That is the place to go! I think you'll find Dr. Fry very helpful if you write him an email. I know that his previous research used westerns, and that he is supposedly working on something new with easterns. I have to warn you, extracting from hognoses is very difficult given the low yield from their glands. I hope you've got support from your professors, it is dangerous for the snake since it has to be anesthetized, and you may need permits to collect and experiment on them. In all honesty, this is not a project for an undergrad, it's more appropriate for a PhD thesis. But I'd be interested in hearing details about your particular ideas for a project.

Below is an article to get you started. In addition, I have included some of the posts that Dr Fry has written on this forum. It's disorganized, but it included necessary information. I also have a huge collection of hognose lit, so if you want access to that you'll have to write me an email.

PLEASE! Keep us (or me) updated, this is great interest to me! Good luck!

_____________________________

Toxicon. 1992 Jul;30(7):775-9. Related Articles, Links

Effects of Duvernoy's gland secretions from the eastern hognose snake, Heterodon platirhinos, on smooth muscle and neuromuscular junction.

Young RA.

Oak Ridge National Laboratory, Health and Safety Research Division, TN 37831-6050.

Duvernoy's gland secretions (100 micrograms/ml) from the eastern hognose snake, Heterodon platirhinos, induced a neuromuscular blockade in the isolated frog sciatic nerve-gastrocnemius muscle preparation and effectively antagonized acetylcholine and histamine responses of the rat duodenum preparation. The Duvernoy's secretions (100 micrograms/ml) produced a reversible, excitatory effect in the guinea-pig ileum in vitro. Mice administered the secretions (100 mg/kg, i.p.) exhibited minor, transient signs of toxicity. These preliminary observations provide evidence for toxicity of H. platirhinos Duvernoy's gland secretions but do not warrant categorizing the potential toxicity of this species with that of proteroglyphous, solenoglyphous, or the more venomous opisthoglyphous species.
________________________________________

Dr Fry’s page
http://www.venomdoc.com/
http://www.venomdoc.com/toxin_molecular_evolution.html

http://forums.kingsnake.com/viewarch.php?id=317741,317948&key=2004

Yes they are venomous and it is a proper venom, not 'toxic saliva'. This is because venom evolved only once in snake evolution, at the very base of the advanced snake tree, long before any of the 'colubrid' snake families popped up. The hognosed snakes are in the Xenodontinae snake family, along with the Brazilian smooth snake (Hydrodynastes gigas), aka false water cobra (a totally inappropriate name since cobras don't occur in South America!).

The venom is rich in enzymes which means that it typically will cause little more than localised swelling (neurotoxins are present in only low concentrations) and it is produced in rather small amounts. Enough to help settle a toad down but not enough to cause severe reactions in humans.

http://forums.kingsnake.com/viewarch.php?id=326807,331695&key=2004

>>Relative to elapids and pitvipers, they do not have the adaptations for injecting venom deep into tissue.

Of course not. Highly developed fangs were an additional improvement that came after the evolution of venom, and such fangs have evolved at least four times on separate occasions. The enlarged teeth were an improvement over normal teeth and facilitate the venom by creating deeper wounds. Grooving was a subsequent improvement to help channel the venom and hollow hypodermic needle fangs the ultimate adaptation.

Evolution of the venomous snakes could be viewed as:

1. Venom - the obvious first step and happened only one time (which is why the term 'Duvernoy's gland' to distinguish 'colubrid' venom glands from elapid or viper homologs, has been abandoned and venom gland used in all cases).
2. Enlarged teeth - quite variable as to which and evolving on quite a number of occasions, this is why aglyph and opisthoglyph are artificial distinctions that shoe-horn a unrelated snakes into entirely contrived distinctions.
3. Grooved teeth - yet again quite variable and independently evolving on numerous occassions.
4. Hollow fangs - variable yet again. The elapid fangs are unrelated to the viper fangs and the Atractaspidae fangs appear to be a third evolution. The highly mobile and extremely advanced boomslang fangs, while not hollow are deeply grooved and represent a fourth evolution of advanced architecture.

> The paper I cited made a pretty good case for the enlarged teeth being used primarily for holding struggling live prey.

The paper you are referring to was written before the relationship of the venoms of the various 'colubrid' families in relation to the atractaspids/elapids/viperids was worked out. This is not to say that large teeth are not useful in holding prey but they are more likely to be enlarged ones in the front of the mouth rather than tucked all the way in the back (ie the large front teeth in Ahaetulla species).

http://forums.kingsnake.com/view.php?id=569842,572565

>I always wondered about the popping the toad thing too. The grass snake we have here in Holland (Natrix natrix helvetica) has the enlarged teeth backwards in the mouth too. It has no venom like the hognose. It does have the duvernoy gland (spelling?).

Actually, it does have venom. Not enough to typically cause any notable signs in humans but its still there. Enough to stun a frog or fish but thats all it really needs. Hence those cute little fangs.

We've shown some of the snakes we think of as 'non-venomous' actually have venoms as potent as a death adders. However, they produce it typically in small amounts. The potential severity comes down to simply how much is actually delivered. The toxicity is there. For the majority of these snakes, the amount delivered is so trivial in bites to humans that for all practical (legislative) purposes, they are completely harmless.

http://arachnoboards.com/ab/archive/index.php/t-22919

The article can be a tad confusing but here's the short and sweet of it. North American hognose do have venom but it is specific to their prey and on humans only causes swelling. Garter snakes also posses what could technicaly be called venom but again it is harmless to humans. The rest of the North American colubrids are totally harmless. The colubrids that were tested were mostly Asian Rats and very few of them are considered harmful while a few of them do contain the same toxins as hot snakes in their saliva. The concentration is far too small to do any harm in most species though. The Duvernoys gland is only associated with rear fanged species so it isn't present in most colubrids.

http://www.[bleep]/forums/showthread.php?t=7044

>Then you of course believe his, every colubridae is venomous?

We've proven the single origin of snake venom (predating the major colubrid diversification) in this article:

http://www.venomdoc.com/downloads/2..._an_Arsenal.pdf

>As though I totally respect and admire a lot of his work,

Thank you

>I however disagree.

Based on what evidence?

>Everyone that I know who has worked and studied this species has not found any evidential trace of any vasoactive autopharmacologic compounds, that I am aware of.

Absense of evidence is not the same as evidence of absense

>In fact it's stated to be bacterial.

Bacterial infections take days to show up, not minutes or hours. The bacterial red-herring is advocated by Kardong since he simply will not accept colubrids in fact possessing a true venom despite the evidence to the contrary. I'm not sure why but all it does is obscure the evolutionary history.

>If the snake was truely venomous than it would take the same affect on each one of us.

Not necessarily, particularly since the reactions to colubrid venoms will vary tremendously contingent upon the amount of venom actually delivered. This is the key, that the venom is delivered much slower and inefficient than say in an atractaspidid, elapid or viperid. Colubrids do not have stored venom as part of a high pressure system terminating in hypodermic needle like fangs. Rather, their venom is secreted as needed and delivered through a much less efficient manner (there are of course some notable exceptions to this such as Dispholidus, Philodryas, Rhabdophis). So, the colubrids are much less likely to envenomation which is one of the reasons their venom has gone overlooked for so long. It was assumed fangs preceeded venom rather than the other way around. Venom preceeding fangs makes perfect evolutionary sense since there cannot be a strong selection pressure for the evolution of advanced fangs in the absense of potent venom worth delivering. We have in fact shown that some of these snakes are in fact as potent as a death adder

http://www.venomdoc.com/downloads/2...%20neurotox.pdf

We haven't studied the hognose in detail yet but have analysed its venom by mass spec, with it being just as complex as the others.

http://www.venomdoc.com/downloads/2...roidea_RCMS.pdf

We will be doing the venom gland cDNA library after we finish the current lot.

> Though, the 'venom' is said to be worked through the gums, like our saliva, this would be you would pretty much get the same reaction from anyone bitten and chewed on.

It is very unlike our saliva which doesn't contain neurotoxins. However, we do have very dirty bites and the reactions produced to our saliva are due to bacteria. As everyone who's ever been around small kids (which seem to have a tendency to chomp on each other) knows, human bites can lead to some nasty infections a few days later.

>Now amphibians, on the other hand, has had some fun times with these injections, however very few died and any reaction was recorded several hours after each bite. Not a very productive venom, even for it's native prey.

The amphibians showing some sensitivity to the venom should be a nice clue that it is in fact a venom. The slow nature of the deaths may have to do with the composition of the injection rather than the venom itself. They may have pipetted more saliva than venom out of the mouth. Unless they milked the snake right and stimulated the gland properly, then the venom may have actually still been up in the gland.

>Plus we all know how sensitive amphbians are.. I just can't buy the fact they are venomous, because if I did, I'd have to buy the fact all the colubrids are venomous, and if I did that I'd have to buy all things which produce an LD50 are venomous and if I did that what fun would it be in any of this?

What you want and what nature is, are unfortunately two very different things in this case.

> If hognoses are venomous, and he factuates his actual studies to it, then I will believe Hogs are truely an exception when it comes to venom..

We have the mass spec results, showing a venom profile very similar to other venoms that we have already purified and sequenced toxins from. We even pulled out potent neurotoxins from the radiated ratsnake! In any case, we'll be sequencing toxins out of Heterodon in the next group of snakes. Hognosed being venomous is consistent with the rule rather than them being an exception.

>Heck, even gilas and beadeds follow the delivery system rule..

Heterodon have a delivery system (better than many other colubrids actually), their rearfangs aren't actually so far back once the maxillary bone is rotated. There is no way these fangs are for popping toads. Anyone who's ever tried to kill a cane toad in Australia knows they don't pop .......... unless you catch them properly with the tyre.

One thing that needs to be stressed is that there is a huge difference between colubrids all being venomous and the relative danger posed. Hognosed snakes for example while venomous are extremely unlikely to be able to produce a bite of any clinical consequence, let alone life-threatening. Most colubrids are technically venomous but for practical (ie. legislative) purposes, the majority should be considered harmless. This is because while the venoms are typically very potent, they are usually produced in small quantities (sublethal even if the full shot is gotten in) and the delivery mechanism is not as rapid as that of an atractaspidid, elapid or viperid. They are able to deliver enough venom to settle down their prey item, which is the entire point of having venom.

However, at least one member of each of the major families has produced some nasty clinical effects:

Homalopsidae: Enhydris have caused bleeding problems
Xenodontidae: Philodryas are lethal
Colubridae: Dispholidus and Thelatornis are lethal
Natricidae: Rhabdophis have killed people and are the poster child for why we need to find out which are dangerous and which are trivial. They were sold on the pet trade as brightly coloured Asian garter snakes until they caused some kids in the US to bleed out of every orifice.
Pseudoxyrhophiidae: Madagascarophis are anecdotally reported as having a nasty bite
Psammophiidae: Malpolon, Psammophis and Rhamphiophis have all caused bites producing neurotoxic and hemorrhagic effects

We've been playing around with the antivenoms and so far none of the existing ones have been able to touch the venoms. This reinforces the point that while they are less likely to get you with a good bite, if they do you are screwed.

If you map the species above (which noone will disagree with as being truly venomous) over the taxonomical tree, you will notice that they do not form one tidy little group but rather are scattered over the full bredth of the tree. To account for your theory of not all colubrids being venomous, this would necessitate multiple independent evolutions of venom. The above list, however, is very much not an exhaustive link of colubrid type snakes that have caused clinically significant envenomations and therefore we'd have to have venom evolved on even more occassions. Hardly a parsimonious explanation. Particularly in light of the demonstrated homology of the venom glands (the term Duvernoy's gland has been abandoned as it is the same gland), demonstrated through comparative morphology and embryology and the homology of toxins not only shared between viperids and elapids but also the demonstrated homology of colubrid toxins e.g.

http://www.venomdoc.com/downloads/2...olubritoxin.pdf

So, at the end of the day what has emerged from the results is that snakes are even cooler than we thought they were and that evolution never ceases to amaze. Its fun stuff indeed to be playing with.

Cheers
Bryan

http://forums.kingsnake.com/viewarch.php?id=317741,317948&key=2004&show_threads=2

>>The term "venomous" has some nasty connotations associated with it that certainly make MY ears perk up, especially when it comes to legislation that specifies venomous reptiles (i.e., prohibition, permitting, etc). Although Heterodon is not lumped into the category as "hot" (that I assume is a commonly accepted slang term for those reptiles that are truly life threatening), how do we go about separating those "cute little snakes" from ones that can truly put you down or rot a limb off? I am hoping that we can have better term to refer to them as so as to prevent any panic related lumping with the hots, especially by lawmakers.

Thats a very good question and one without an easy answer. They are venomous (as are virtually all other 'colubrids'). However, this should not be confused with dangerous. The vast majority of 'colubrids' are not dangerous despite being venomous. However, each of the 'colubrid' families has dangerous species within it. I think it should be on a genus by genus basis. If a genus has had a species located within with a well documented severe or even lethal envenomation, then entire genus by implication should be regarded as truly venomous. Philodryas is a good example of this, with fatalities having occured from bites. In contrast, the garter snakes have caused only minor localised reactions typically with only one neurotoxic envenomation having been recorded so this genus should be treated as harmless for legislative purposes. It is a process of education and preemptive maneuvers rather than letting the morons at PETA and API dictate the agendas. It is a similar situation to all spiders being venomous but only select ones being able to cause severe envenomations.

I am firmly opposed to any blanket inclusion of all the different families of 'colubrids' into the category of venomous in regards to legislation. This would be an utterly assinine approach.

>>I guess as hognose forum users, we should always answer questions like these as, Venomous? Yes. Dangerous? NO.
>>

Exactly.

>>Question is now, do you consider the account in the following link to be a severe envenomation?

I would consider that to be about the maximum ability of a hognosed and certainly not life threatening and therefore not a severe envenomation. The localised effects were obviously rather 'interesting' but it was not life threatening nor was there permanent tissue damage.

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Virginia Herping
http://groups.yahoo.com/group/VaHS
Virginia Herpetological Society online store
http://www.cafepress.com/vaherpsociety

"The irrational fear of snakes is the only excuse a grown man has... to act like a complete sissy" - Colchicine

wow, thanks alot for all the ifno. I've seen dr. frey's site before and i think i will drop him an email. One of my main concerns/questions for him is what is the best way to extract venom. I know in the field, all eastern hogs i've encountered play dead quite readily and usually hang thier mouths open, but after that i wasnt sure what to do, like take a micropippetor and suck up some of the saliva. I do realize this is most likely a big undertaking for an undergrad, but i can at least start it up and possiblly continur the project in grad school. I will definetely keep everyone posted on any progress and once again, thanks so much for all the help!
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1.0 Normal Cornsnake
1.0 Sumatran Short Tail Python

>> but after that i wasnt sure what to do, like take a micropippetor and suck up some of the saliva.

This is why I thought you didn't know what you were getting into. Collecting saliva alone with not be sufficient. You have to make sure you are collecting genuine venom and not all the other oral liquids. I only have a fundamental understanding of the process and there's going to be some red tape. Dr Fry described anesthetizing the animal, and then using a drug to stimulate the venom gland. Once you talk about anesthesia and controlled substances, I think all sorts of animal welfare protocols kick in. You probably will need to have your study plan approved by your school's animal welfare board (or whatever it is called there), not to mention having a knowledgeable professor that can acquire the controlled substances needed to do the study.

You haven't mentioned a professor yet, but I think you need to THOROUGHLY discuss it with someone to determine the feasibility first. Ideally, you'd find a new grad student who is looking for a thesis topic and get THEM to do this study and go through all the red tape while you just have fun in the lab!
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Virginia Herping
http://groups.yahoo.com/group/VaHS
Virginia Herpetological Society online store
http://www.cafepress.com/vaherpsociety

"The irrational fear of snakes is the only excuse a grown man has... to act like a complete sissy" - Colchicine

Don't forget that I have a huge list of hognose literature. I'm just not willing to put it on a public forum since it's taken way too time to assemble. Email if you want it.
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Virginia Herping
http://groups.yahoo.com/group/VaHS
Virginia Herpetological Society online store
http://www.cafepress.com/vaherpsociety

"The irrational fear of snakes is the only excuse a grown man has... to act like a complete sissy" - Colchicine

Once you have the venom... what are you going to do with it?
Again, Dr. Fry will have some insight to this and I share your enthusiasm, but from my experience, undergrad's are kinda sh t on by U's as far as funding for studies goes.

Ian