More lizard families than previously believed are venomous

Study shows more to a lizard bite than a nasty nip By Wendel Broere

More lizard families than previously believed are venomous, including several species that are popular pets, scientists said on Wednesday.

Until now, pain and swelling from lizard bites assumed to be non-venomous were attributed to the bacteria that thrive on bits of meat left between their teeth from their scavenging diet.

However, the symptoms are actually from the venom, a finding which could have implications for medical research, said Dr. Bryan Fry of the University of Melbourne, lead author of the research published online by the science journal Nature.

"The venom is the perfect knock-out punch by monitor lizards to their prey like small mammals and lizards," he told Reuters. It stops blood clotting, rapidly drops blood pressure and heightens the feeling of bite pain.

His team of international scientists isolated crotamine -- the classic venom of rattlesnakes whose bite can be fatal to humans -- in the eastern bearded dragon, a popular pet.

However, the bearded dragon's delivery system is primitive and it is present in such small amounts it would not harm a human.

Fry said Indonesia's Komodo dragon -- the world's largest lizard, weighing up to 350 lbs (160 kg) -- was also venomous.

MEDICINES

It had previously been thought that only two families of reptiles were known to have venom systems -- advanced snakes and Helodermatid lizards.

This study demonstrates there are venom toxins in two more lizard families: monitor lizards, such as the Komodo dragon, and iguania such as the bearded dragon and green iguana, but their toxin secreting glands are smaller than those of snakes.

The study effectively doubles the number of potentially venomous reptile species to 4,600 from 2,300.

"There are so many more reptiles with venom now than we previously thought. That fact itself has massive implications for a vast array of areas, whether it be evolution, drug design and development or ecology," Fry said.

Snake toxins are already widely used in medicines to treat epilepsy, haemophilia and thrombosis. The new lizard venom toxins and their molecules present a huge unexplored resource for drug design and development, according to the researchers.

"Milking the big monitors was quite simple, just gently squeezing the glands would result in 40-50 milligrams (dry weight) of liquid venom pooling at the base of the teeth," Fry said.

This means a big Komodo dragon could have more than 200 milligrams ready to delivery at any time, he said.

Fry was anxious that lizard owners should not be unduly concerned by the findings.

"If you're dinner then the venom plays a role, but if you're human it's most likely just to make your hand throb. We don't want people to suddenly be afraid of their pets," he said.

"Nor do we want any silly laws being passed against the keeping of these lizards."

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This is very interesting stuff for sure. Click here to see the original article by Dr. Fry (dial-up warning - 3 MB).

ARE bearded dragons Iguania?
I have been under the impression that Iguanids and Agamids separated from common ancestors a loooong time ago. Being no more closely related to one another than either is to any other lizard family.

Remember the thread where a fauna member was bitten by a savanna monitor (I believe) and he had a serious reaction. So serious in fact that he ended up going to an Emergency room? I think this happened in September of this year. Maybe this is what precipitated that reaction.

coyote said:

ARE bearded dragons Iguania?
I have been under the impression that Iguanids and Agamids separated from common ancestors a loooong time ago. Being no more closely related to one another than either is to any other lizard family.

Remember the thread where a fauna member was bitten by a savanna monitor (I believe) and he had a serious reaction. So serious in fact that he ended up going to an Emergency room? I think this happened in September of this year. Maybe this is what precipitated that reaction.

Click to expand...

I remember that thread. This does bring up interesting new theories as to why he had the reaction he did. I would like to see what else they discover if they decide to take their studies even further.

It was trpnbils

http://www.faunaclassifieds.com/forums/showthread.php?t=72266

coyote said:

ARE bearded dragons Iguania?
I have been under the impression that Iguanids and Agamids separated from common ancestors a loooong time ago. Being no more closely related to one another than either is to any other lizard family.

Remember the thread where a fauna member was bitten by a savanna monitor (I believe) and he had a serious reaction. So serious in fact that he ended up going to an Emergency room? I think this happened in September of this year. Maybe this is what precipitated that reaction.

Click to expand...

Very interesting article...

Here's something I found regarding the relationship between Iguanids and Agamids...Granted, it was taken from a caresheet by Melissa Kaplan...in the paragraph after this one she talks about how Iguanids come from a "rainless or essentially rainless" area of the world, so maybe take this with a grain of salt:

Iguanids may be distantly related to the Old World agamid species, which includes such lizards as the Northern African and Middle Eastern spiny-tailed, or dab, lizards (Uromastyx spp.) and the Philippine and Chinese water dragons (Physignathus spp.). Whether iguanids evolved from agamids, or agamids from iguanids, or whether they are a classic example of convergent evolution, is still a matter of debate."


Although I don't have the monitor that bit me anymore (traded it in for a nice BCI), it'll still take some consideration on my part before I handle a Savannah again. But I still handle water dragons, beardies, and large prehensile-tailed skinks (which, from what I understand, sometimes cause severe reactions from their bite) on a daily basis at work without thinking twice about it.

I don't know if what was mentioned in this article had anything to with what happened to me, but I asked around on several forums and took a LOT of strongly worded, highly opinionated, and accusatory s**t for even suggesting that what happened was even remotely related to the bite (none greater than on Kingsuck.com, which is why you won't find me there anymore). Although I only have basic knowledge of the medical end of all of this, anaphylactic shock was the major problem when I got bit...which suggests an allergic reaction. Wouldn't venom, even "mild" venom like what's mentioned here, cause a different kind of reaction? I did find probably half a dozen other people that had reactions to skink and monitor bites, and their stories all sounded very similar to mine, but none of us could draw any conclusions from it.

Regardless of whether it's related or not, I'm interested to see where this research goes. Thanks for the heads-up Coyote!

Click to expand...

TrpnBils said:

. Although I only have basic knowledge of the medical end of all of this, anaphylactic shock was the major problem when I got bit...which suggests an allergic reaction. Wouldn't venom, even "mild" venom like what's mentioned here, cause a different kind of reaction? I did find probably half a dozen other people that had reactions to skink and monitor bites, and their stories all sounded very similar to mine, but none of us could draw any conclusions from it.

Regardless of whether it's related or not, I'm interested to see where this research goes. Thanks for the heads-up Coyote!

Click to expand...

Don't bee stings cause this also? They sting, you get envenomated, and granted it is an allergic reaction to the bee venom, but it is still caused by a venom.
At least from what I know. Like you, I know little about the medical end.

Great post. I for one, being inthralled with venomous creatures my whole life, find this very interesting. I would defenately like to follow these studies to their end.


Ciao,
Rick

crotalusadamanteus said:

I would defenately like to follow these studies to their end.

Click to expand...

Then hold on to your hat. Dr. Fry is looking at at least one group of PYTHONS as being venomous. That report will be released next year.

Wait a second, this thread accuses Komodo dragons of being venomous when science says otherwise. We KNOW it's bacterea in he mouth with them, research on both it and the wounds infected by it has been done how many times? And I find it hard to believe a lot of these lizards could be venomous anyway... No rivets in the teeth.

We know that venomouse lizards like gila monsters have rivets in their teeth that the venom runs down, and you can still see where the venom comes out in the fangs of venomous snakes. Where is the venom supposed to come from in say... An eastern bearded dragon's mouth? Is it just supposed to drool it out?

DibDip said:

Where is the venom supposed to come from in say... An eastern bearded dragon's mouth? Is it just supposed to drool it out?

Click to expand...

That is pretty much what the article implies, yes.

DibDip said:

Wait a second, this thread accuses Komodo dragons of being venomous when science says otherwise. We KNOW it's bacterea in he mouth with them, research on both it and the wounds infected by it has been done how many times?

Click to expand...

No, we USED to know that it was a bacterial thing.
Now evidence sugests other wise. I found it a little hard to believe also, but with technology the way it is, we as people have found out that we were wrong about many things that we once thought we knew.
Dr. Fry is well known for his studies in these fields. Not having a doctorate, or even a masters, I would have to take what he says to be true. He's far more educated than I am, and probably even you. No offense meant, it's just that these more educated people who spend there time in the field doing research, and publishing their findings is how people like usGET educated. We would know virtually nothing about our herps otherwise.

How you ask? Through secretion perhaps. Salivatory glands for one. Salivatory glands, or at least modified ones have delivered venom for who knows how long in all kinds of Viperidae. The same way the Gila, and Beaded lizards do.

But if you read it thoroughly, I believe it said that there is little danger to humans. It is meant for their prey. Correct me if I am wrong.

And welcome to fauna.

Ciao,
Rick

crotalusadamanteus said:

No, we USED to know that it was a bacterial thing.
Now evidence sugests other wise. I found it a little hard to believe also, but with technology the way it is, we as people have found out that we were wrong about many things that we once thought we knew.
Dr. Fry is well known for his studies in these fields. Not having a doctorate, or even a masters, I would have to take what he says to be true. He's far more educated than I am, and probably even you.

Click to expand...

As much as I would like to just accept this new evidence as fact, I can't...not yet anyway. Yes, this guy is a whole lot smarter than you or I, but so are the researchers who, in every related study prior to this, presented the bacteria idea as absolute fact...just like Dr. Fry is doing with the venom idea. I'd like to see other studies done on this, and I'll tend to remain skeptical until I do. Not because I'm cynical, but because the MAJORITY of research out there is contradictory to this study.

I agree somewhat. Let's say i am more open mined to it do to the technilogical advances that mankind has undergone. How long ago did they pronounce "bacterias" as the cause of death when bitten by a komoto? I would say in the same era of time, scientist never even dreamed that a hair follicol or a single sperm cell was a more acurate form of ID than a fingerprint.

With the advances that we have made in microbiology alone, I would have to say that I lean towards the evidence recently produced, over evidence produced 30 yrs ago.

I'm willing to bet others like yourself have been bitten over the years, and had such reactions to these bites. Probably many that didn't make the public eye.

But also, I will follow up on these studies and see what happens. I'm not closeminded to them being wrong, just more inclined to trust todays methods of research over the old.

Ciao,
Rick

Well, I suppose all that's reasonable... But I'm still a little skeptical and would like to wait for a little more information on research dealing with this befoe completely accepting it as fact. And thanks for the greeting, Rick.

This is all we need. More fuel for the anti reptile people to use against us and get bearded dragons banned as venomous reptiles.

Steve

Don't Let Go of Your Hat Yet ...

I attended a lecture by an MSU herpetologist recently, and he spoke of studies currently being conducted on the toxicity of colubrid saliva, specifically garter snakes. Early indications suggest that even they have a form of venom.

He also pointed out that this in no way makes them dangerous, and should be downplayed in public, to avoid a public relations disaster.

I think we will hear a lot more about this in the next few years. I hope there can be some benefit to mankind (i.e. "Lifesaving drug discovered in garter snakes") from this research. Herpetology could certainly use the "good press".

jsrocket said:

I attended a lecture by an MSU herpetologist recently, and he spoke of studies currently being conducted on the toxicity of colubrid saliva, specifically garter snakes. Early indications suggest that even they have a form of venom.

Click to expand...

I for one have extremely bad reactions to Garter snake bites. I swell bad, itch, and hurt where I am bitten with extreme burning pain. If this does not prove there is something in their saliva I don't know what will. I will take a photo time line next time I am bitten.

crazycorn said:

I for one have extremely bad reactions to Garter snake bites. I swell bad, itch, and hurt where I am bitten with extreme burning pain. If this does not prove there is something in their saliva I don't know what will. I will take a photo time line next time I am bitten.

Click to expand...

Do you actually plan on getting bitten again? Sounds like with that kind of reaction, the key would be to "NOT" get bitten again. LOL

Rick

I've read some of Dr Fry's work, but not any of this more recent stuff. Not having read the new work, my opinion is that this is just a result of the new technologies we now have. I know what you're thinking.........Duh, John that's what we're talking about. What I mean is, we may need to redefine the meaning of venomous, in the context we use it. We are now able to test for things we weren't able to in the past. Heck, maybe someone can test human saliva and find an enzyme that has "venomous" properties. Cobras, Rattlesnakes, Heloderma, etc., all have well defined "venom systems", even some of the rear fanged snakes have somewhat defined "systems" though not as complex. These systems include the venom, venom delivery method (fangs, grooved teeth), and actual venom producing and holding methods. IMHO, I don't think just because some of these animals have an enzyme or two in their saliva, that they are venomous.
I didn't read the account of the Savannah (sp?) monitor bite, but as mentioned, it sounds like an allergic reaction, which can range from simple localized itching, and redness at the site, to a more generalized rash or hives, to a full systemic anaphylactic reaction (a true life threatening reaction). Venom could cause such a reaction in people, but so can just about anything that a person develops a sensitivity to. Just the past day or two ago, a teen age girl died of anaphylactic reaction from kissing her boyfriend, who had been eating peanuts, which she was allergic to (according to the news). We humans are becoming more and more sensitive to "irritants", cases of asthma, and allergic reactions to lots of things, that use to be "harmless". I've been bitten by Savannah's as well as many Species and ssp. of Garter Snakes, and Water snakes native to CA, AZ, TX, as well as one or two eastern states, and never had any problems. Like I said, I haven't read the latest, but at this time I think it is "much ado, about nothing" or whatever that saying is.

reptilebreeder said:

). We humans are becoming more and more sensitive to "irritants", cases of asthma, and allergic reactions to lots of things, that use to be "harmless".

Click to expand...

whooops.....should be; We humans are becoming more and more sensitive to "irritants". Cases of asthma, and allergic reactions to lots of things that use to be "harmless", are increasing.