Question for the venom experts...

[shaggybill]

I am writing an article for my not-yet-uploaded website on "what is the most venomous snake?" I was wondering if anybody knew what snake holds the record for most deaths per year, and which snake has the highest venom yield?

I figure some sort of viper has the biggest yield, but I dont know that for sure.

If Dr. Brian Fry reads this, I was wondering if I could use this exerpt from your website:

"Venom yield must also be considered. For example, Pseudonaja textilis (Eastern brown snake) is around two and a half time more toxic than Oxyuranus scutellatus (Coastal taipan) but the coastal taipan injects up to twenty to thirty times more venom. Thus, the net result it the coastal taipan injecting eight to twelve times more lethal doses than the eastern brown snake. "

I will make it so its not exactly word for word, but I would like to use that example, and I dont want to "plagiarize" what you wrote without permission.

Thanks

[Dr. Bryan Fry]

G'day your royal shagginess,

no worries on using any of the material from the site, thats what its there for. As for which causes the most deaths, thats a tough one. When the saw-scaled was a single species, it was considered as a contender. However, now that its been revealed to be a half dozen or so, its not in the running. No comprehensive work has been done fragmenting the puff adder (and theres no reason for it to expect to be so) while the Asiatic cobras have been split into the quite a few more species. SO, at the end of the day I'd say the puff adder would be the most likely culprit.

As for biggest venom yield, thats actually held by the Australian mulga snake (Pseudechis australis) at 1.39 grams!

Cheers mate
B

[Brodie]

Dr. Fry...very interesting stuff mate....... Just wondering how many humans 1.39g of Mulga Snake could kill? (ball Park figure)
Cheers Mate

[Dr. Bryan Fry]

The mulga is much less toxic than the inland taipans, brown snakes, various sea snakes, death adders, tiger snakes, etc. Lethal dose would probably be a hundred milligrams or even a bit more (compared to about a milligram for inland taipan venom). This would put it on par with the eastern diamondback rattlesnake in toxicity.

Cheers
B

[Maik Dobiey]

Whats the matter with the venom yield of Ophiophagus hannah?
And can't one say that the Dendroaspis polylepis is the most dangerous snake for humans? As I heared the rate of mortality after a bite is the highest... But maybe because of lacking good medical care where this Mamba apears?
That's just what I thought reading this.

Cheers

[Mustangrde1]

Dr Fry. You bring up a Interesting subject. I have noticed a very clear differance in my eyes to anyway in regards to Cobra's. Ray Hunter recieved several shipments 1 was from Egypt and one was from Tanzania. On these shipments were Naja haje. The appearance were as I said very diffrent in appearance. I was curious if there is any ongoing studies or work done in the Taxonomy ond or reclassifications of the Naja species. I have also noticed that Naja sagittefera<sp> and Naja Kaouthia are very similar in appearance from pictures I have seen. could this be the same species but only a local variance?

Scott

[Dr. Bryan Fry]

Hi all,

Maik, I've milked quite a few kings species, including heaps of the Malaysian monster species. I'd reliably get upwards 600 milligrams but never close to a gram. Got 750 from a 3 meter taipan once. As for the mambas being the most dangerous, its all of course relative. Dead is dead. Anything else is academic. As for the mamba being that unusually lethal, its partly an influence of if the person dies, it was certainly a mamba. If they lived, then it was something else.

Scott, the various 'Naja' in Africa are being sorted. Its more complicated than just a few regional variants and several cryptic or even bloody obvious new species. Where it gets cute is that melanoleuca and nivea are not even 'Naja'. Boulengerina and Paranaja are closer to being Naja than they are. Utterly different genus.

Cheers
B

[Jeremy]

Yeah! I was going to try and draw you in with this topic, seeing as your now are a frequent visitor on this forum but I quess the work was done for me:-)

Regarding the Naja haje mess, man, just wanted to get you take on one form, which was a ssp and is now not even that! The past named Naja haje leglionis(spelling). A mutal freind of ours picked up a pair of neonates and they closest thing I can compare them too is an Inland Taipan!!! They have pitch blk heads and very light, almost cream colored bodies. Even annulifera babies(un bannded form) look similar to typical Naja haje untill they grow a bit.

I know morphological differences cant be the key factor in differing sp but good lord, ive never seen such a drastic difference with in the haje complex before. Have you by chance tested any venom from this race? If so, have you noticed any differences, however minute between them and classic Naja haje?
Hopefully this form is included in the current work being done on African Naja. If not, it should be!!

Also, you say that Boulengerina and Paranaja have been found to be more closely affilated with Naja then previously thought. Does Aspidelaps fall anywhere in this? I feel from just external observations that they are even closer then Paranaja. Hell, from what I have gathered, Paranaja doesnt even rear up and spread a hood!! Granted neither does A.scutatus but, well, anyway:-)

One last question regarding venom yeilds. First, that is amazeing about the Mulgas!! I have always heard they had an s load but never thought of them to be have the most!! Being that your work occasionaly includes disecting and inspecting venom glands in the sp you work on, how do lets say Bushmasters and EDBs compare to Mulgas as far as gland size is concerned? Could it be that the mulgas are less conservitive with the venom they release, hense the largest yeild? Just going by head size alone, a huge EDB or Bushmaster (or even a western gaboon) heads blow away even the largest mulgas I have seen and I always though of these guys as beeing numero uno for venom yeilds. Could it be that elapid glands are longer and go further down into the neck region (kinda of like a long glanded coral snake or Night adder but not that extream) and vipers and pitvipers are more bulky but shorter?

Welp, sorry for the bombardment of questions and comments mate. Just trying to get my facts strait and get your opinion. Hope everything is going well!!

All the best PWD!!

BTW, what the heck has Tim been up too? I havent seen him post in a while.

Peace me amigo,
Jeremy

[Mustangrde1]

Ok now all this cobra talk brings up another animal I would love to have clarified and that is " Naja Hannah " Why is it a Ophiophagus and not a Naja as it once was.

[Dr. Bryan Fry]

Hey Jeremy,

Not too up on the particulars of the African Naja's, expecially the whole haje taxonomical dumping ground. I know a fair bit of genetic work is being done on the Naja species themselves (as well as the 'genus' as a whole). I wouldn't be suprised at all for additional species to be described within haje and annulifera as well as nigrocollis and melanoleuca.

It isn't a case so much of Boulengerina and Paranaja being close but rather more that melanoleuca has no buisiness being in Naja (other than having a hood which isn't the sole domain of true Naja).

For the sieze of the venom glands, mulgas have bloody big venom glands. Also, elapid venom is often more concentrated than viper so it can pack more venom into the lumen simply by increasing the protein (venom) content at the expense of the water. Spitting cobras obviously have more watery venom but sea snakes have even more concentrated venom. There is a difinate shape difference between elapid and viper venom glands but elapids don't typically extend into the next (long-glanded coral snakes are an exception but so are Atractaspis and Causus).

Twinky is doin' well, enjoying the plethora of nubile undergraduates to choose from ;-)

As for Mustangrde1's question, Ophiophagus is utterly unrelated to Naja. Utterly. Elapsoidea (African garter snakes) are genetically actually one of the closest relatives of Ophiophagus, ignoring the fact that Elapsoidea are dinky little things. There are also about seven species of Ophiophagus, some of which are as different genetically as an eastern diamondback rattlesnake is from a neotropical rattlesnake.

Cheers
B

[Mustangrde1]

Dr Fry. Thank you for answering. With that answer now another comes up. I know certain species have been reclassed such as the Naja hannah to ophiophagus hannah and some trimersaurus to Bothrops or reversed. What and how is the base's for the reclassification of a species. God I love Living Science always changing always evolving.

Thanks Scott

[Dr. Bryan Fry]

Hi Scott,

Most of the reclassification done now is utilising genetic data (which is very revealing) as opposed to superficial external features. Its a case of a long overdue house cleaning now that the right tools are available. In some cases this means putting a few species back under the umbrella of one name (but this of course does not mean that there cannot be regional variations, this is to be expected for any wide ranging species). In other cases it showing cryptic species (they look alike but are quite divergent) or just sorting through messes (like the whole 'Elaphe' taxonomical dumping ground which was the ratsnake equivalent of dumping anything that wasn't obviously a cobra or viper into the 'colubrid' family).

Cheers
B

[Mustangrde1]

DR Fry I appreciate the answer greatly.

Do you feel with all the field equiptment available now that more or less actual specimen collecting for preservation is needed?will evidance from the field from living specimens be a better meens then an aged pickled reptile?

I am curious to if you see differances in Lab animals vs Wild caught vs long term captive animals. Does possible prey and water sources deviate the animals in any way that you have notices. And is it possible that cross contamination of animals in a lab setting differ from wild samples.

Thanks Scott

Scott

[Dr. Bryan Fry]

Hi Scott

Preserved specimens always have a need. While DNA can tell us who's who, its still nice to be able to identify the bloody things without having to use PCR! So, morphological features need to be determined that can be used to identify a particular species.

As for the captive animals, the impact on venom composition shouldn't be appreciable. The major difference with captive animals is usually getting a mixture of venoms from different regions of the same species if they are pooled together.

Cheers
B

[Mustangrde1]

Much appreciated Dr Fry. just out of curiosity what is your most memorable incounter with a sea snake . I would love to some day see them in their natural habitat but living in Florida i doubt thats going to happen any time soon lol.

[Dr. Bryan Fry]

Most memorable encounter? Hmm.... its a toss up between finally capturing a Stoke's sea snake (after six years of looking) and the time that a big horned sea snake bit me and almost killed me (took eight months to recover!).

Cheers
B