Reptile & Amphibian Forums

Since when are the Hognose species venomous? Rearfanged? What about garters? Someone else was saying that his eastern black necked garters were rear-fanged also.. This pic. came off of the hognose forum and I guess I never realized that the Hognose were even potentially mildly venomous. Is this making sense? Visit the hognose forum if your confused (as I apparently am)... Guess you learn something new everyday...

Kerry in Dallas

-----
verrykerry@yahoo.com
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes

They aren't mildly venemous. They have rear fangs, meant for popping the toads they prefer to eat. Toads will fill themselves with air to become both intimidating and harder to swallow, so the hognose evolved with a method of taking care of that issue.

As for being venemous, I'm no hognose expert, but that's the first I've heard of it. It would be cool if they utilized the poison from the paratoid glands of the toads they swallowed as a defensive toxin though, like dart frogs and the ants they eat, but that's pretty far fetched and highly doubtful. I'm thinking maybe someone is confused and thinking of the very mild neurotoxin that many watersnakes possess to make the holding of fish/slippery prey a bit easier.

Some of those more familiar with north american non constrictors may be able to shed some more light on the subject of venom, but the fangs are not meant for venom injection at all.

>>They aren't mildly venemous. They have rear fangs, meant for popping the toads they prefer to eat. Toads will fill themselves with air to become both intimidating and harder to swallow, so the hognose evolved with a method of taking care of that issue.
>>
>>As for being venemous, I'm no hognose expert, but that's the first I've heard of it. It would be cool if they utilized the poison from the paratoid glands of the toads they swallowed as a defensive toxin though, like dart frogs and the ants they eat, but that's pretty far fetched and highly doubtful. I'm thinking maybe someone is confused and thinking of the very mild neurotoxin that many watersnakes possess to make the holding of fish/slippery prey a bit easier.
>>
>>Some of those more familiar with north american non constrictors may be able to shed some more light on the subject of venom, but the fangs are not meant for venom injection at all.

Actually they (like many other "harmless" colubrids) are, in fact, venomous. They produce a 3FTx (three finger toxin) called Colubritoxin. This toxin is produced by a gland known as Duvernoy's Gland. A great many Colubrid snakes have active Duvernoy's glands. In fact, if I'm not mistaken, Dr. Bryan Frye has dropped the use of the term "Duvernoy's Gland" and is simply referring to it as a venom gland. Colubritoxin is actually at least as potent drop-for-drop as Cobratoxin, and is very similar in composition. The trick is that MOST of the Colubrids that produce the toxin don't have the effective venom delivery systems of snakes such as Elapids, Crotalids and Viperids and don't produce as much of the toxin so they can't deliver enough to be dangerous to humans. There are exceptions, though...Boomslangs and Twig Snakes are notable examples. Hognose Snakes (at least at their present evolutionary state) are still not dangerous to humans, but they do produce the toxin.

Dr. Frye has some of the results of his ongoing studies on this subject on his website:

venomdoc.com

-----
We do not inherit the Earth from our ancestors; we borrow it from our children. Ralph Waldo Emerson

Very interesting. I don't buy it about constricting colubrids but I can certainly see it being a fact in snakes which employ the 'overpower' method of hunting.

I'll need to read his site at some point to get some more info on it and just how he's doing his research. I'm fairly interested in his methods of determining the biochemical composition of their saliva/venom and it's toxicity. Even given that they don't have the delivery methods of elapids, their venom would do significant tissue damage at the site of the bite wound. It takes tiny tiny amounts of elapid and viper venom to cause some serious flesh injuries to humans, far less than fatal amounts.

I did read the hognose forum briefly after my previous post and saw images of hognose bites and the swelling which occured. I've seen a venomoid cobra take a good chomp on someone's hand and he had much worse swelling (up to his shoulder), and the snake is definately venomoid. The swelling is caused by the bacteria in the animal's mouth and the nerve and blood vessel damage from the teeth.

I'll reply to this post after I've educated myself a bit on this Dr's findings and methods. If they're truly scientific in nature I'll be inclined to change my views

You may not be familiar with Dr.Frye but I assure you he knows his stuff, he's considered to be one of the world's leading venom researchers. Widely published and well respected. Even had a few specials about him on the discovery channel if I remember correctly.
-----
"Nothing happens in contradiction to nature, only to what we know of it."

I'm not making any statements about anything until I read more, which I probably won't be able to do for a few months. Until that point though I wouldn't consider myself informed enough to make any statements for or against his findings.

..as I understand it, many of the snakes currently in the family colubridae will soon be in other families. This would include hognose, ringnecks, pine woods, as well as others.
On a side note, a friend had a bad swelling from a hognose "envenomation".
Saliva is a potent elixir in some animals huh?
:Mark

As was said, most colubrids do have venom for subduing prey, but the effects are weak on people. I did hear one case about a semi serious bite from a hognose, venom in your body can cause an allergic reaction, just like some people get from bee stings. Bees have a weak venom as well, but some people develop allergies to it. Its not the venom that kills, but the bodys reaction to it. The guy went to the hospital but was alright. Ive heard cases from exotic colubrids as well, but I do believe the only ones to cause death are boomslangs and twig snakes. Dont forget, all spiders have venom, but not all spider bites cause problems for people. Some may cause swelling from allergic reactions in some people. For the most people, the effects will be minimal. Someone doing a lecture out here said he let a few local rear fangs bite him and they caused local pain an redness for a short period of time. It had kind of a burning sensation.

Not to argue with any of the possibly very true statements you made, but I got bit by a large subadult anaconda and my entire leg felt like it was burning for a week, from secondary infections.

Although the effect may be similar, comparing bee venom to snake venom isn't exactly ideal, reason being the bee venom is meant for defense, snake venom is meant for offense.

The point to comparing bee venom and snake venom is that they can cause allergic reactions. So can medicine. Any foreign proteins can cause allergic reactions, which can kill. This is why harmless rear fanged snakes should still be considered potentially dangerous. I have heard of allergic reactions to harmless snakes, but not death. If you get to a hospital, they can handle the reaction pretty well.

This is why harmless rear fanged snakes should still be considered potentially dangerous. I have heard of allergic reactions to harmless snakes, but not death.

I heard from a doctor in STHA www.kingsnake.com/stha of a death due to a bite from a patchnose (Salvadora grahamiae). I don't know any details, though.

Also, there is a report in one of the peer-reviewed herp bulletins about a reaction to a bite from a wandering garter, Thamnophis elegans vagrans. This was interesting to me since I keep one. I don't even handle mine, just in case I'm one of those allergic types. I have been bitten by T. marcianus, in fact chewed on with the apparent intent of ingestion by the little snake, but other than some localized swelling nothing much came of it.
-----
Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet

That is very interesting, I would like to know more about it.

>>That is very interesting, I would like to know more about it.

So would I. I can't even remember which of the docs told me that. Might've been Dr. Kiel. Keep pinging me about it in the future and I'll try to get more info.
-----
Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet

I just thought of something: I heard that there has never been a documented death from a sidewinder bite. This is a species that is considered dangerous, but a patchnose is not. Then again, sidewinders produce bad effects nearly every time and require hospital treatment, while patchnose bites do not. Strange the way some things work isnt it?

I heard from a doctor in STHA www.kingsnake.com/stha of a death due to a bite from a patchnose (Salvadora grahamiae).

I was there at the meeting when it was mentioned. However, I have a very hard time believing that. I think maybe they forgot to mention he was chasing the patchnose into oncoming traffic...

I was there at the meeting when it was mentioned. However, I have a very hard time believing that. I think maybe they forgot to mention he was chasing the patchnose into oncoming traffic...

Heh. I need to contact whoever it was to get more info. Was it Kiel?

I suppose it's possible, but highly improbable. The victim probably had just the right (or wrong, in this case) combination of factors providing an increased allergic reaction to the saliva.

Regardless, I'm glad I didn't try to pick up any of those mean ones in TX. Did you hear Joe's field got plowed under last week?
-----
Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet

I fully agree with what you're saying, that harmless snakes can cause allergic reactions. However, what are they allergic to? Are you saying that to have an allergic reaction to something it must be mild venom? I know lots of people that are allergic to dog and cat dander...

If i'm taking you wrong correct me. I read your post to state that some colubrids must have mild venom since some people have had allergic reactions to it...

Again, you stating that even "non-lethal" venemous animlas should still be treated with the respect of lethal ones is 100% correct.

Actually what Im stating is that mild venom has been discovered in almost all colubrids. The exceptions would be kings and gophers and other constrictors. Dr. Frye (which posts in the venomous section) has done a lot of research into this. While the effects on people are minimal (or none) the foreign protien can still cause a reaction. This is why people are careful when it comes to rear fangs that do have swelling effects on people because it is more likely. There may be a slim chance for the reaction, but one should be aware of the possibility so that they can catch it.

There's sort of a misconception at play here, I think. The Alpha-4 Colubritoxin that Bryan has isolated from the saliva of these animals is not a mild toxin. It is an extremely potent toxin, on par with Cobratoxin. The reason that people don't generally suffer dangerous envenomations is twofold. First, most of these animals don't produce enough of the toxin to be able to deliver a dangerous bite and, secondly, they don't have the venom delivery apparatus to be able to effectively deliver the venom.
-----
We do not inherit the Earth from our ancestors; we borrow it from our children. Ralph Waldo Emerson

What I mean by mild is that the effects are mild. All venom has potency to kill, thats what it is designed for. I understand what you are saying but when I think of mild Im thinking of mild effect in people. I am aware of Dr. Frye's findings of the cobratoxins in mildly venomous snakes. One thing (actually several things) that they lack are the various other components to elapid and viper venom that colubrids lack. This is not to downplay the danger of cobratoxin by itself, but there are several compounds in elapid venom that have potential to kill. As you said, colubrids dont have the quantity or apparatus do deliver fatal bites (with a few exceptions) but people do show allergies to cobratoxins when bitten by elapids, and the same is possible from most colubrid bites. Now swelling around the bite site as posted earlier is probably due to the toxin in higher quantity than usual (chewing the venom in so they deliver more) as opposed to anaphalactic symptoms of allergic reactions.