How dangerous are rattlesnake bites ??
eli...@vt.edu
question he posted about snakes, asking for some hard numbers on which is
most poisonous:
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I have located my copy of Diesenbach's "Handbook of Poisoning" (7th Edition,
1971) and have some "hard" numbers on the relative toxicity of the members
of the Crotalidae (rattlesnakes) in the western USA.
The figures listed are for LD50, i.e., the amount needed to cause 50%
mortality in mice when injected intravenously or intraperitoneally. There
is of course some species variation in susceptibility to any poison, but
using mice as a "standard" animal is routine in toxicity testing.
Nine species of the genus Crotalus are listed. Of these the most toxic
venom comes from the Mojave rattler (C. scutulatus), with an LD50 of 0.21 mg
per kg.
The least poisonous is the Sidewinder (C. cerastes) at an LD50 of 4.00 mg/kg.
The largest snakes, the Eastern and Western Diamondbacks (C. adamanteus and
C. atrox, respectively) have toxicities of 1.68 mg/kg (fairly high) and 3.71
mg/kg (fairly low).
Using these standards the least poisonous snake in North America is the
Copperhead (Agkistrodon contortix) with an LD50 of 10.50 mg/kg. It's very
rare for someone to die of a copperhead bite, though it has happened.
Crotalid venoms are hemolytic: they cause destruction of the red blood
cells. The extremely poisonous snakes of other countries often have
neurotoxic venom; the only example of this in North America is the venom of
the Coral snake (Micrurus fulvius) which has a reported toxicity of 0.97
mg/kg. For purposes of comparison, the neurotoxin of the Indo-Pacific
Beaked sea snake (Enhydrina schistosa) is extremely dangerous at 0.01 mg/kg.
Coral snakes are treated with considerable respect here, for obvious
reasons, but more people die from rattler bites than coral snake bites
because the coral snake is relatively unagressive and easily identified
thanks to its bright coloration. It's found all along the Gulf Coast of the
US, and as far inland as central Texas (I have seen them in College Station).
The relative toxicities of venoms are not the entire story, however. The
larger snakes, like the Diamondbacks, may actually have a higher incidence
of fatalities because they can store and potentially inject more venom than
the small ones, even though the venom is less toxic in most cases. A
Western Diamondback can have as much as 375 mg of venom in reserve compared
to about 90 mg for the Mohave rattler. A given strike by a given snake may
inject no venom; or it may inject up to 75% of the stored amount.
There are something like 15-20 snakebite deaths per year in the USA; many
more people die from allergic reactions to insect bites and stings.
Snakebite is easily avoided. Almost all bites (especially from striking
snakes like rattlers) are on the lower leg and a good pair of snake-proof
boots or chaps provides complete protection. Good gloves and attention to
where you place you hands in snake country also are important.
I hope this information is of use to you.
The Elitist
James Keane
Excellent post. Thanks for taking the time to send it to the group.
: This is a copy of a note sent to Dr. Reinald Meurers in response to a
: question he posted about snakes, asking for some hard numbers on which is
: most poisonous:
:
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: I have located my copy of Diesenbach's "Handbook of Poisoning" (7th Edition,
: 1971) and have some "hard" numbers on the relative toxicity of the members
: of the Crotalidae (rattlesnakes) in the western USA.
: The figures listed are for LD50, i.e., the amount needed to cause 50%
: mortality in mice when injected intravenously or intraperitoneally. There
: is of course some species variation in susceptibility to any poison, but
: using mice as a "standard" animal is routine in toxicity testing.
: Nine species of the genus Crotalus are listed. Of these the most toxic
: venom comes from the Mojave rattler (C. scutulatus), with an LD50 of 0.21 mg
: per kg.
Here in Arizona, it's often referred to by it's nickname, "The Three
Step". That's because you only get three steps after being bitten, and
then you die! I believe this name comes from Mexico (where, or course,
it's in Spanish).
: The least poisonous is the Sidewinder (C. cerastes) at an LD50 of 4.00 mg/kg.
Interesting. Sidewinders are the *only* snake I have even seen act
aggressively. These guys (and gals - don't want to be sexist) will
actually come after a human. I woonder if there are a disproportionately
large number of deaths by Sidewinders compared to their toxicity because
of this.
: The largest snakes, the Eastern and Western Diamondbacks (C. adamanteus and
: C. atrox, respectively) have toxicities of 1.68 mg/kg (fairly high) and 3.71
: mg/kg (fairly low).
Another good reason to live in the West! ?*)
: cells. The extremely poisonous snakes of other countries often have
: neurotoxic venom; the only example of this in North America is the venom of
: the Coral snake (Micrurus fulvius) which has a reported toxicity of 0.97
: mg/kg. For purposes of comparison, the neurotoxin of the Indo-Pacific
: Beaked sea snake (Enhydrina schistosa) is extremely dangerous at 0.01 mg/kg.
: Coral snakes are treated with considerable respect here, for obvious
: reasons, but more people die from rattler bites than coral snake bites
: because the coral snake is relatively unagressive and easily identified
: thanks to its bright coloration.
If I'm not mistaken, I believe that they also have very small mouths
compared to rattlers. I don't think they can actually bite you in the leg
since they can't get their mouths open wide enough for this. I remember
hearing somewhere that most people bitten by corals are messing with them
(usually thinking they are a harmless snake have a similar coloring) and
are bitten on the web between the thumb and index finger. I can't swear
that this is true, though.
When I was a kid, I used to see Gila Monsters (the only poisonous lizard
in North America) on a regular basis. I haven't seen one in years,
though. It's a pity; these animals have their place in the desert.
Unless a rattler poses a threat to people or domesticated animals, I just
leave them alone (and they generally return the favor).
Regards,
J. Sean Keane
Sam A. Kersh
>This is a copy of a note sent to Dr. Reinald Meurers in response to a
>question he posted about snakes, asking for some hard numbers on which is
>most poisonous:
>*******************************************************************************
>I have located my copy of Diesenbach's "Handbook of Poisoning" (7th Edition,
>1971) and have some "hard" numbers on the relative toxicity of the members
>of the Crotalidae (rattlesnakes) in the western USA.
>..............................deletions...............................
>Crotalid venoms are hemolytic: they cause destruction of the red blood
>cells. The extremely poisonous snakes of other countries often have
>neurotoxic venom; the only example of this in North America is the venom of
>the Coral snake (Micrurus fulvius) which has a reported toxicity of 0.97
>mg/kg.
You normally have to do something really stupid to be bitten by a
coral snake. Their mouth is small and about the only place they can
bite is the webbing between the fingers or ear lobes. For some
strange reason, some people confuse the coral with the king snake and
play with it. Could turn into a fatal case of stupidity.
The only snakes I've had a problem with were water mocs. Talk about
attitude problems, they are damned aggressive at times.
Most of the people I know who were bitten by a rattler never heard a
thing. Stepped over a log or boulder or reached under a prickly pear
for a downed dove and ZAP.
>..............................deletions...............................
>The Elitist
Sam A. Kersh
sa...@i-link.net