Reptile & Amphibian Forums

Posed this question on another venomous forum. I’d like to see the response here too.

“I have seen the LD50 for King Cobra rated, or reported as being 1.31 iv

On venomdoc site- I’d like to think is the best one...
(http://www.venomdoc.com/LD50/LD50men.html)

and on this other site the number 0.35 iv
on this site- actually Singapore Scorpion site
(http://members.tripod.com/~c_kianwee/rpotent.htm#Snakes)

And venom yield at 300-500mg.

The Asiatic or Asian elephant from Thailand is smaller than the Indian. It will weigh between 3000-5000kg. I have heard stories of King Cobras killing elephants working in the forest. Supposedly the King is clever enough to bite them in the area around the toenail, their most vulnerable spot.
If you assume a smaller elephant (3000kg) wouldn’t that make the mg of King Cobra venom required 1050mg? (3000 x .35) And that would actually kill 50% of 100 tested, I presume?
If the yield is 300-500mg of venom, how could a bite, even from a very large cobra to a very small elephant ever be fatal?
And that is assuming the bite would be iv, not sub cute.

If you used the 1.31 x 3000 it would take 3930mg of venom.
I need help understanding the LD-50 table I guess...

Are LD-50 always mg/kg?

I have searched every link I could to learn as much about LD-50 and there really is nothing out there, unless I’m missing something. Anybody have a webpage link to share to learn more?”

So that was the body of the post, the response has been, basically, the LD-50 table isn’t practical to use for converting grams of mice into kg of elephants, or that the yield would be much higher in a snake being stepped on,
etc.
So can someone explain- is it jungle folklore or truth that a King cobra can kill an elephant?
Maybe a job for the “Mythbusters”?

Upscale, it's always been my understanding that kings can kill elephants by biting them just above the toenail, as you mentioned, and at the end of the trunk.
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Venomous snakes---best hobby on earth!
Bill Huseth

Keep in mind with LD50 tests that they are to healthy mice and only within a definate time period. What might happen several days later cannot be extrapolated nor can the effects of preexisting conditions (eg kidneys) be predicted. LD50s are only a very rough guide and do not necessarily reflect the complexities of reality.

Cheers
Bryan
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Dr. Bryan Grieg Fry
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Department of Biochemistry,
Bio21 Institute,
University of Melbourne
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http://www.venomdoc.com

>>And venom yield at 300-500mg.

Also note that this is sort of an "average" yield from an "average" king during milking. I've never actually seen an info on how these numbers are arived at. A LARGE adult being stepped on by an elephant might be expected to produce at least 2-3 times that much I would bet.
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What goes up must come down...unless it exceeds escape velocity.

You only get so much venom, even from a mad cobra trying to get a @#$#% elephant off it’s back.

I believe the stories are true that some elephants used in the harvesting of teak or whatever are lost to king cobra bites, I’m just trying to figure out how it is possible, given the amount of venom to the massive size of an elephant. It just doesn’t seem possible!

From Wikipedia-
“In fact, a King Cobra can deliver enough venom to kill a full-grown Asian Elephant in 3 hours.”

From National Geographic-
“the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant.”

This is probably a good example of how hard it is to find real info.

The quote from NG (2/10 oz., 7 ml) would work out to about 2000-3000 mg or so of dried venom.

NG's web site seems to be very short of fact checking and probably got this number from another site.

I've seen it stated as follows on different sites:
2 cc
2/10 oz.
2 oz.

I don't know which, if any, can be taken seriously (clearly not the last one).

I love Wikipedia and it's a great starting point, but it's not a reliable source in many categories, especially snakes.

For instance, much of the wikipedia page on the King is just minor rewording of the NG page, including the obvious exaggerations like a King standing up and looking a man in the eye.

I'm sorry I can't tell you where to look for the info you want, but I can tell you it's not NG or Wikipedia in this case.
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What goes up must come down...unless it exceeds escape velocity.

I THINK I read an article somewhere that explained a case, step by step, of an elephant being killed by a king bite(if I can find it again I'll post it). It's been a couple years and the article was based on hearsay, but I'm sure it's happened at least once-anything's possible in extreme conditions(the one I heard about took place over days, not hours though). Guns & Ammo even wrote an article once that mentioned 2 elephants that were killed with single shots from a .22 rifle-separate incidents, not the same shooting of course. I would personally think that was less possible than a slow death from a heavy dose of venom.

Thanks to all. Could it be that once the diaphragm (neuro)fails, it doesn’t matter how big the victim is, you die, LD-50 rating matters not. An elephants body mass is off the charts, but the venom acts to shut down the neurotransmitters (or whatever the actual process is) exactly as it does in the mouse. The body weight of the elephant (for neurotoxin) has nothing to do with it?

Yes and no. Stricly speaking, body mass probably does not matter, BUT...

Greater blood/lumph volume will dilute the venom more and a more massive diphragm will have more synapses which will require more venom molecules to paralyze. I suspect the blood/lymph volume and number of synapses in the diphragm will be roughly proportional to the body mass for a given species...

That proportion might be significantly different between a mouse and am elephant though. I'm not sure about that, though I suspect an elephant's skeleton probably makes up a much higher percentage of it's body mass for instance...
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What goes up must come down...unless it exceeds escape velocity.

It's also very possible that the mechanism for death between a mouse and an elephant may be different. Where the mouse might die directly from the effects of the venom, the cause of death for an elephant could be indirect. Elephants don't do well lying down. Just their weight can cause respiratory problems in that position. Enough venom to knock an elephant down could well kill it over time. Add in the effect of the venom on the diaphragm muscle, and it's not hard to imagine that it might take proportionally less venom to kill and elephant than a mouse.

deg

I’m thinking along those lines. It’s like the lethal amount for a man is the amount that prevents you from driving to the hospital for antivenom. The elephant dies as a result of the venom, but it’s the labored breathing that kills the mighty beast. Or something like that...

There are so many factors that come into play that it is impossible to give you the answer you are looking for.

Different animals react to venoms differently as WW said on the other forum. Maybe elephants are more sensitive. Maybe it was a very old animal. Maybe it was allergic. Maybe the king was 30 ft long. Maybe the elephant fell off a cliff and the keepers decided it would make a good story to say it was bitten by a king instead. Maybe it had a heart attack from seeing the king. Who knows.

Until the day comes when they do a wide spread LD50 test on elephants, with venom from every O.hannah specimen in the world I am afraid your question will never be answered.

If a tiny scorpion or blue ring octopus can kill a human which is 100 times larger then it is it really that surprising that an elephant was killed by the largest venomous snake in the world?

>>If a tiny scorpion or blue ring octopus can kill a human which is 100 times larger then it is it really that surprising that an elephant was killed by the largest venomous snake in the world?

Ah, but I think that's part of the reason this is such an interesting question. The king is hardly the most venomous (per mg). In terms of mouse LD50, it's venom is rather mild compared to several other snakes in the elephant's range...and 70 times less potent than an inland taipan, but they are not likely to run into elephants.
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What goes up must come down...unless it exceeds escape velocity.

Thats the thing though. LD50 show us how toxic a venom is to a mouse. Not elephants, human, whales etc lol There is no way of knowing how dangerous O.hannah venom is to an Asian Elephant. It could be similar to Sydney funnel web venom. Most animals laugh at funnel web venom but to us its life threatening. Also keep in mind that aside from Aborigines there are no primates in Australia so there is no evolutionary reason other then dumb luck. It just happened. Maybe king venom is horribly strong to elephants. There havent been enough envenomations cases in regards to O.hannah biting elephants to come to any conclusion.

There is also the issue of the snakes themselves. Venom varies from specimen to specimen so even snakes from the same population can have differing venoms. Then take into account that kings are extremely wide spread and will probaly be separated into many species and or sub species. There could be a king with venom that equals Inland Taipans for all we know. It just hasn’t been tested since we think that all kings are the same. Not likely but you get my point (btw, though inlands are obviously toxic as heck there haven’t been enough envenomation reports on humans to determine that it is the most toxic snakes species to humans. One could argue tat its not since I don’t think there have been any human fatalities associated with the species)

Last but not least is quantity. Kings have a HUGE amount of venom! More so then probaly anyother species though there are some obvious contenders. A.contortrix venom is generally not lethal to humans but if you were injected with 800 mg it probably would be lol

It is an interesting question none the less and I didn’t mean to come off as a jerk. I just think way to much thought has been put into a question that can never have an answer lol

>>It is an interesting question none the less and I didn’t mean to come off as a jerk.

I didn't think you were being a jerk, and note that I just said it was interesting, not neccessarily meaningful...

>>I just think way to much thought has been put into a question that can never have an answer lol

If no one put much thought into questions without answers, think of all the unemployed philosophers...it would be tragic.
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What goes up must come down...unless it exceeds escape velocity.

LOL good point Larry!

TIMES OF ZAMBIA (Ndola) 02 February 98 Black mamba is chief of African snakes
If ever a snake captured the imagination of people in the bush, it is the black mamba, the chief of African snakes .
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King Cobra, or hamadryads are dangerous to both humans and animals. Their poison has been credited with killing an elephant - the snake bites the trunk tip or the soft skin between the toe-nails. Particularly where working elephants are used in forests to move timber. It is probably due to the elephant disturbing the nest of the cobra, which by the way builds some kind of nest and lays its eggs which it defends. …

DESERET NEWS (Salt Lake City, Utah) 08 December 99 King cobra is most dangerous snake in world: Asian snake is prince of poison and king of mean (Phil and Nancy Seff )
When a panel of herpetologists (scientists whose specialty is snakes) was asked which snake they considered the most dangerous in the world, they almost unanimously agreed that the king cobra, Ophiophagus hanna, ranks No. 1. …
… Being neurotoxic, the venom can kill a man within 15 to 20 minutes of being bitten, and can topple an elephant.
In 1991 a work crew cutting timber in central India was startled when one of their work elephants suddenly trumpeted in agony and went berserk. It attacked everything standing, including other elephants. Much destruction resulted from its 20 minute rampage, when it suddenly stopped, sank to its knees and gently rolled over dead. The unfortunate beast had unwittingly stepped on a king cobra that reacted in protest, as any creature might do when stepped on by a full grown elephant. After biting the elephant on it right front knee, the snake, of course, expired and became a tasty evening meal for the workers.
http://deseretnews.com/dn/view/0,1249,145009186,00.html?

I'll look later in 2002-07 archives ... I'm on an Army task right now and free time is a touch of a premium. Wes

mg/kg is just another expression for 1 part per million. Some state LD50 as micro-grams/grams, but that is just the same.

One of the frequently met misunderstandings about LD50s is that they can be "linearly extrapolated" from the lab mouse (usually 20 gr) to humans (70 kg) to elephants (which can come as 500 kg to 4 ton packages). This is not the case. Although overall, snakes with low LD50 (= highly toxic venom) are usually also those most dangerous to humans (where data are available), telling that LD50 values in fact DO provide some meaningful measure for a whole-venom toxicity, it is nevertheless also true that primates (including humans) are often much more sensitive to venom than mice or rats. From this it follows that the venom quantities required to do harm to a human are often much smaller than the about 3.000-times (70.000 gr weight vs. 20 gr. weight) the quantities that were required to do the job if there were a linear relationship. Thus, LD50 values are not "meaningless", as sometimes stated, they just have a limited predictive value when it comes to extrapolation to other organisms.