Toxicity of Tarantula venom

Chris R

Arachnopeon
Joined
Sep 30, 2003
Messages
46
I recently watched a program on a National Geographic channel dealing with the toxicity of North American poisonous snake venom during a defensive or offensive strike (at prey animals). The previous assumptions were that defensive strikes were either 'dry' or low in venom toxicity.
This limited study showed the opposite to be true, that defensive strikes were actually higher in toxicity than administered during offensive attacks on prey animals. I found this show and the results fascinating.
Do you think a parallel study into the toxicity of tarantula venom during offensive/defensive strikes would cooberate these findings?
Any thoughts from our more learned members?
 

Crotalus

Arachnoking
Old Timer
Joined
Dec 14, 2002
Messages
2,433
Chris R said:
I recently watched a program on a National Geographic channel dealing with the toxicity of North American poisonous snake venom during a defensive or offensive strike (at prey animals). The previous assumptions were that defensive strikes were either 'dry' or low in venom toxicity.
This limited study showed the opposite to be true, that defensive strikes were actually higher in toxicity than administered during offensive attacks on prey animals. I found this show and the results fascinating.
Do you think a parallel study into the toxicity of tarantula venom during offensive/defensive strikes would cooberate these findings?
Any thoughts from our more learned members?
Venomous snakes that defend themselfs from a predator, for example a human, are known to deliver a dry bite, to safe venom for a prey. This is clearly shown by no envenomation took place, or a very mild envenomation.

If they used prey animals for this study, how do they determine what is defensive strike and what is offensive?

How do you determine this from a prey which the snake know he can eat?
And whats the name of this program? Would like to see it.

/Lelle
 

Chris R

Arachnopeon
Joined
Sep 30, 2003
Messages
46
They actually performed surgery on the venom ducts of the test snakes. Measuring electrodes were attached surgically, to the venom ducts, then to a computer, to measure the actual amounts of venom used.
Prey animals used were lab mice to test the offensive strikes. To test defensive strikes, an artificial 'gloved hand' was used to elicit the defensive strike.
One of the problems was trying to prompt a defensive strike as the snake usually tried to avoid any encounters by moving away. Once the defensive strikes occurred the results were, again, fascinating. It certainly turned around my thinking of 'dry' bites.
Little research exists, in this area of venom toxicity, concerning tarantulas.
Size considerations being the obvious drawbacks. I don't know how a person could contact National Geographic for a copy of the show.
I posted this to stir the gray matter of AB members for opinions.
 

ShaunHolder

Arachnoangel
Old Timer
Joined
Jan 29, 2004
Messages
828
It's definatley interesting but I wouldn't say that the same is true in tarantulas. First of all ever genus is very diffrent in it's method of delivering a defensive bite.

Unline snakes, some Tarantula's have utricating hairs that they can flick off thier abdomen and legs to chase away prey. They also tend to give a threat posture in addition to flicking these hairs before making a defense attack.

I don't think it's as simple as saying tarantula's in general, because all tarantulas have venom. And every genus has very diffrent behaviors. For example, A. Avics have been known to be very docile, and use try bites often to defend them selves. H. Lividum is the exact opposite, biting several times in the same place using it's venom.

A study on bites would be interesting, but I dont think a generalization would be as acurate since diffrent kinds of T's defend themseleves diffrently. :p
 

tarantula666

Arachnosquire
Old Timer
Joined
Jul 21, 2004
Messages
140
toxicity

that defensive strikes were actually higher in toxicity
don't they mean that the amount of venom varies and not the toxicity???
or can snakes and spiders dilute their venom before injecting????
 

MilkmanWes

Arachnobaron
Old Timer
Joined
Jul 9, 2004
Messages
489
For example is an Avics poop ickier in a defensive blast or when they are just doing it out of necessity.

I say ths tongue in cheek, but now I gotta wonder if there isn't some kind of difference in the enzymes in the two that may make it more unpleasant.


ShaunHolder said:
A study on bites would be interesting, but I dont think a generalization would be as acurate since diffrent kinds of T's defend themseleves diffrently. :p
 

Crotalus

Arachnoking
Old Timer
Joined
Dec 14, 2002
Messages
2,433
Chris R said:
They actually performed surgery on the venom ducts of the test snakes. Measuring electrodes were attached surgically, to the venom ducts, then to a computer, to measure the actual amounts of venom used.
Prey animals used were lab mice to test the offensive strikes. To test defensive strikes, an artificial 'gloved hand' was used to elicit the defensive strike.
One of the problems was trying to prompt a defensive strike as the snake usually tried to avoid any encounters by moving away. Once the defensive strikes occurred the results were, again, fascinating. It certainly turned around my thinking of 'dry' bites.
Little research exists, in this area of venom toxicity, concerning tarantulas.
Size considerations being the obvious drawbacks. I don't know how a person could contact National Geographic for a copy of the show.
I posted this to stir the gray matter of AB members for opinions.
Since venomous snakes do not allways deliver a dry defensive bite and sometimes give the predator a full venom injection, I wonder what good comes out of this research?
The toxicity dont change in offensive or defensive bites, just the amout of venom injected.

/Lelle
 

oogieboogie

Arachnoknight
Old Timer
Joined
Mar 29, 2004
Messages
238
Crotalus said:
Since venomous snakes do not allways deliver a dry defensive bite and sometimes give the predator a full venom injection, I wonder what good comes out of this research?
The toxicity dont change in offensive or defensive bites, just the amout of venom injected.

/Lelle

Now your dealing with "what ifs" so to speak. The point of the research was to see, in general, which type of strike delt more venom. According to the research, a defensive bite delt more venom then a prey item.

The only problem that I could see in this research would be that a lab mouse, is a much smaller item then a human hand. Therefore the snake might realize this, and inject more venom to compensate for the larger predator. Why use all that venom on a tiny little mouse when all it takes is a little.

Also if you think about it in terms of survival, it makes sense that they would use more venom in a life threatening situation. Their life could be on the line, they would probably pull out all the stops.
 

Archangel

Arachnoknight
Old Timer
Joined
Jul 28, 2004
Messages
208
You might want to watch "Venom ER" on Animal Planet. It talks about all of this stuff.

Allen
 

MizM

Arachnoprincess
Old Timer
Joined
Jan 13, 2003
Messages
4,915
Ahhh yes. Our wonderfully nasal Dr. Bush! He's a very bright guy and does much research on snakes.

Another problem with venom theorizations... each INDIVIDUAL of a particular species reacts differently to different stimuli. For example, one G. rosea might flick, threat, slap and dry bite before ever using venom while another might inject all they've got at the first disturbance!

I've noticed that my H. lividum masticates the b.b.q. skewer when I tease her out of her burrow, but I've NEVER seen a drop of venom. Does she KNOW it's metal and she can't kill it? Would she invenomate if she sunk her fangs INTO something?
 

Pheonixx

Arachnoprince
Old Timer
Joined
May 24, 2004
Messages
1,219
i would imagine toxisity would depend on the individual getting bit, diff people have diff tolerances. Ex- lately i have noticed T. blondi hairs dont bother me much, as yester day i got a handful of them and it only tingled a little bit. as for bites i have been bitten by many things snakes, lizzards and spiders (no t's yet) and several wasps. the only one to affect me seriously was a wasp, my hand swelled up about 4 sizes from normal, i had to go to hospital for that.

side point- myGF asked me yesterday if a "snakebite kit" would work on a T bite. i had no idea but it seems like a good question to ask in this thread, would it?
 

FryLock

Banned
Old Timer
Joined
May 17, 2004
Messages
1,656
Pheonixx said:
side point- myGF asked me yesterday if a "snakebite kit" would work on a T bite. i had no idea but it seems like a good question to ask in this thread, would it?
Like a Sawyer extractor im sure if it covered both bite wounds BTW both the very bad t bites iv had where from ONE fang :D
 

oogieboogie

Arachnoknight
Old Timer
Joined
Mar 29, 2004
Messages
238
You guys are nit-picking too much. *lol*

The experiemnt, as it sounds, was not to state that every snake does things the same way. More so in general, on average, what they do. Of course it depends on the individual snake, spider or whatever. But in general they found it to be true that they tend to release more venom in a defensive state.

Pheonixx said:
i would imagine toxisity would depend on the individual getting bit, diff people have diff tolerances.
the toxicity of the venom doesnt depend on the individual being bit. The venom will have the same toxicity if it bites a piece of wood or flesh. o) The reaction people have to that said toxicity is what varies.
 
Last edited:

Crotalus

Arachnoking
Old Timer
Joined
Dec 14, 2002
Messages
2,433
oogieboogie said:
Now your dealing with "what ifs" so to speak. The point of the research was to see, in general, which type of strike delt more venom. According to the research, a defensive bite delt more venom then a prey item.

The only problem that I could see in this research would be that a lab mouse, is a much smaller item then a human hand. Therefore the snake might realize this, and inject more venom to compensate for the larger predator. Why use all that venom on a tiny little mouse when all it takes is a little.

Also if you think about it in terms of survival, it makes sense that they would use more venom in a life threatening situation. Their life could be on the line, they would probably pull out all the stops.
I doubt that program test 100 individuals or more, they just took a few and made a few tests. And draw conclusions based on that.
Its infact the opposite, the snake deliver less venom in a defensive strike to save venom for prey (it takes tiome to produce new). Because the strike itself ofter deter a predator to continue the assualt on the snake it doesnt have to inject venom, and a smaller amount of venom surely deter it. However, it CAN deliver the full dose. Generalisations like that show made have no scientific value.

/Lelle
 

oogieboogie

Arachnoknight
Old Timer
Joined
Mar 29, 2004
Messages
238
Crotalus said:
I doubt that program test 100 individuals or more, they just took a few and made a few tests. And draw conclusions based on that.
Its infact the opposite, the snake deliver less venom in a defensive strike to save venom for prey (it takes tiome to produce new). Because the strike itself ofter deter a predator to continue the assualt on the snake it doesnt have to inject venom, and a smaller amount of venom surely deter it. However, it CAN deliver the full dose. Generalisations like that show made have no scientific value.

/Lelle

And where exactly are you getting your information and basing your generalizations on? Also how exactly do you know how many test subjects they used?

If your going to disagree, how about some nice facts to back it up instead of just spouting opinion. O) Im all for people disagreeing, just provide something to back it up with. And dont be so quick to disbelive something new just because the knowledge you have doesnt agree with it.
 

FryLock

Banned
Old Timer
Joined
May 17, 2004
Messages
1,656
I believe Lelle is speaking from his knowledge of Viperidae, im no expert on hots myself but i believe both some Elapidae (Spiting cobras are one that springs to mind) and some Colubridae (the opistoglyphous one's of course) can make venom at a rate of knots.
 

Crotalus

Arachnoking
Old Timer
Joined
Dec 14, 2002
Messages
2,433
oogieboogie said:
And where exactly are you getting your information and basing your generalizations on? Also how exactly do you know how many test subjects they used?

If your going to disagree, how about some nice facts to back it up instead of just spouting opinion. O) Im all for people disagreeing, just provide something to back it up with. And dont be so quick to disbelive something new just because the knowledge you have doesnt agree with it.
I dont think my opinions are generalizations, more a observation on snake behaviour.
I wrote that i doubt they use a higher number of individuals.
You can find info about this in Klauber "Rattlesnakes" and in Greene "Snakes - evolution...".

Also, it differs alot between species so to make a generalization on "venomous snakes" is not good either. Daboia russelli is believed to have a envenomation percentage of ca 75% (info personal correspondence with a person that knows alot of this species), around the same percentage with many rattlesnakes while Dendroaspis polylepis is closer to 100%.

My opinion on this are wellknowned and no theory I have came up with.
I dont really dismiss new info, but in this case I found it poorly done. Atleast based on the info provided here - so I might be wrong.

/Lelle
 

MilkmanWes

Arachnobaron
Old Timer
Joined
Jul 9, 2004
Messages
489
All the toxicity aside, what is the refraction time for refilling the venom sacs? in snakes, tarantulas, and even scorpions.

I know specie and health/diet as well as size may all play a factor in this, but what kind of information is known about speed of venom manufacture?
 
Top