Dry bites is it a conscious choice or just a lottery?.

[Endeavour]

Been reading a little about venomous snakes delivering dry bites. It would appear some do this more than others. My question is. Is this something a snakes makes a 'choice' to do or is it just the luck of the draw as to whether your day is going to turn bad?.

Kindest regards

Endeavour

 

[Bushman]

Good question mate and one that I've wondered about myself.
My thoughts are that because venom is a biologically expensive product to make, that they don't waste it unnecessarily and they will often send out warning shots first.

 

[Leasdraco]

I find this an interesting topic. I think the snakes' ability to control venom output varies between species. It makes sense that they dont want to waste their venom on something that isn't prey. Ive heard from snake 'milkers' that some species or individuals take a fair amount of persuasion to give up their venom. Some, like Red-bellies, often chew for a few moments before releasing venom, so a quick nip is often a 'dry bite', but not predictable enough to take for granted!

 

[The_Geeza]

There was a documentary on this exact subject using a jelly false hand... It proved that different snakes acted different... Even some of the more aggressive snakes were more inclined to dry bite but others were full out delivering a good bite... Dam can't remember what it was called

 

[saximus]

From a biological point of view don't they need to contract specific muscles to release it from the glands meaning that it has to be conscious?

 

[gus11]

There are multiple papers on the rates of venom injection by various snakes, off the top of my head i seem to remember that for most aussie elapids injection rates are very low, this makes sense as stated above venom is expensive to produce, so why waste it. In general venom is used for killing prey, not as an anti-predator defense, an exception to this would be spitting cobras. Snakes have numerous antipredator defenses neck flattening, puffing the body etc., if that fails and they can't flee, dry bites should theoretically occur followed by wet bites. I think looking at the number of bites that occur from snakes around the world and the number of actual envenomation that the majority of bites are dry. Indicating snakes select to inject the venom.

 

[andynic07]

Not all red belly nips are dry bites. Also I thought that the mulga snake had a large venom yield.

 

[Varanoidea]

From a biological point of view don't they need to contract specific muscles to release it from the glands meaning that it has to be conscious?

I was under the impression that the force of the snakes jaws around whatever it was biting squeezed the venom glands. I can't exactly remember where I heard this. From that point of view whether or not the snake injects venom would depend on how committed it was to the bite i.e if it's just a warning it isn't going to bite hard thus no venom.

 

[GBWhite]

Hi Endeavour,

I don't know if snakes can deliberately/intentionally choose to inject venom.

However; I remember discussing this subject with a few friends a couple of years back and I remember someone saying that they read a paper on the ejection of venom by vipers and elapid snakes, (rattlesnakes, lance heads and cobras) where it stated the injection of venom has got a lot to do with the lower jaw gaining enough purchase on a victim to provide a pivot point for the muscles at the back of the upper jaw to be able to clamp down hard enough on the venom gland to force the venom out of the glad, through the fangs and into the victim.

So if this is correct as I assume it is, it would be a reasonable assumption that dry bites occur when the lower jaw of the snake has failed to gain a strong enough grip to cause the back muscles of the upper jaw to apply sufficient pressure on the gland and hence, force venom through the delivery system and into the victim/prey.

So in saying that it can be further assumed that dry bites may happen when a snake "snaps" in a defensive or instinctive action rather than delivering a bite where the intention is a deliberate act to inject venom and immobilize the prey or assumed threat.

George.

 

[mikey_mike]

From a biological point of view don't they need to contract specific muscles to release it from the glands meaning that it has to be conscious?

No, this doesn't require conscious control. The nature of consciousness is an interesting topic in itself, however this question can be answered simply by thinking about a few muscles in your own body.

Heart muscle - learning to control the contractions of this beasty would be a neat trick.
Lower oesophageal sphincter - apparently some sword swallowers have control over this, but the rest of us, sadly no
Uterus - any women approaching childbirth would love to have control
Any muscle involved in a reflex arc - eg patella tap
Any muscle when you're asleep
So many more examples.

It seems self evident that some snakes are more likely to give dry bites than others. It must be influenced by so many factors - the nature & quantity of their venom, it's toxicity towards prey & potential predators, whether or not they had their morning coffee...

 

[dragonlover1]

No, this doesn't require conscious control. The nature of consciousness is an interesting topic in itself, however this question can be answered simply by thinking about a few muscles in your own body.

Heart muscle - learning to control the contractions of this beasty would be a neat trick.
Lower oesophageal sphincter - apparently some sword swallowers have control over this, but the rest of us, sadly no
Uterus - any women approaching childbirth would love to have control
Any muscle involved in a reflex arc - eg patella tap
Any muscle when you're asleep
So many more examples.

It seems self evident that some snakes are more likely to give dry bites than others. It must be influenced by so many factors - the nature & quantity of their venom, it's toxicity towards prey & potential predators, whether or not they had their morning coffee...

haha so funny.....morning coffee...now if I could control my heart that would be a neat trick I could stop my palpitations as I suffer from AF (atrial fibrilations)
but back to post I don't see how it could be a conscious decision as I don't think snakes are intelligent enough to think it through

 

[andynic07]

No, this doesn't require conscious control. The nature of consciousness is an interesting topic in itself, however this question can be answered simply by thinking about a few muscles in your own body.

Heart muscle - learning to control the contractions of this beasty would be a neat trick.
Lower oesophageal sphincter - apparently some sword swallowers have control over this, but the rest of us, sadly no
Uterus - any women approaching childbirth would love to have control
Any muscle involved in a reflex arc - eg patella tap
Any muscle when you're asleep
So many more examples.

It seems self evident that some snakes are more likely to give dry bites than others. It must be influenced by so many factors - the nature & quantity of their venom, it's toxicity towards prey & potential predators, whether or not they had their morning coffee...

Very good post but I am not seeing the link between whether the release of venom is involuntary or not to the nature and quantity of venom. I don't know how true this is but I have heard that mulga snakes have very large muscles that force venom out of the sack and also get similar to a lock jaw and this is why they have such a large venom yield.

 

[GeckoJosh]

According to the person I recently did a ven course with feeding bites (being bitten while feeding the snake) seem too nearly every time cause en-venomation, so going by that I would say they have at least some control over their venom delivery.

 

[mikey_mike]

According to the person I recently did a ven course with feeding bites (being bitten while feeding the snake) seem too nearly every time cause en-venomation, so going by that I would say they have at least some control over their venom delivery.

Makes sense if the primary purpose of venom is to immobilise prey.

 

[GBWhite]

It actually has two primary purposes. It's used to not only immobilise but to assist in the digestion of prey. It's basically a modification of saliva that's found in other vertebrae.

Humans and other mammals have the ability to chew their food where (as we all know) snake don't chew but swallow their prey whole.

Remember when, as a kid we are told to chew our food. Well it's not only to break it into small pieces that can be easily swallowed as a lot of people think. The chewing action creates saliva that when mixed with the food item helps to assist digestion in the gut. The more we chew our food the more saliva mixes with it and the better it digests.

Snake venom contains (as well as many other things) strong enzymes that are very important to assist in the breakdown and digestion of their prey.

Recent research has discovered that pythons have an ancient venom delivery system (not venom glands as such but a system similar to monitors where the venom is stored in small grooves in the jaws and excretes in a form of a saliva) that although not lethal, contains similar enzymes to assist in the digestion of prey (that's why python bites sting and can sometimes become infected). It's presumed that "non venomous" colubrids also have a similar system for the same purpose but it will need further research to confirm.

George.

 

[andynic07]

It actually has two primary purposes. It's used to not only immobilise but to assist in the digestion of prey. It's basically a modification of saliva that's found in other vertebrae.

Humans and other mammals have the ability to chew their food where (as we all know) snake don't chew but swallow their prey whole.

Remember when, as a kid we are told to chew our food. Well it's not only to break it into small pieces that can be easily swallowed as a lot of people think. The chewing action creates saliva that when mixed with the food item helps to assist digestion in the gut. The more we chew our food the more saliva mixes with it and the better it digests.

Snake venom contains (as well as many other things) strong enzymes that are very important to assist in the breakdown and digestion of their prey.

Recent research has discovered that pythons have an ancient venom delivery system (not venom glands as such but a system similar to monitors where the venom is stored in small grooves in the jaws and excretes in a form of a saliva) that although not lethal, contains similar enzymes to assist in the digestion of prey (that's why python bites sting and can sometimes become infected). It's presumed that "non venomous" colubrids also have a similar system for the same purpose but it will need further research to confirm.

George.

What are the points that distinguish venom from saliva.

 

[Barrett]

Hi Endeavour,

I don't know if snakes can deliberately/intentionally choose to inject venom.

However; I remember discussing this subject with a few friends a couple of years back and I remember someone saying that they read a paper on the ejection of venom by vipers and elapid snakes, (rattlesnakes, lance heads and cobras) where it stated the injection of venom has got a lot to do with the lower jaw gaining enough purchase on a victim to provide a pivot point for the muscles at the back of the upper jaw to be able to clamp down hard enough on the venom gland to force the venom out of the glad, through the fangs and into the victim.

So if this is correct as I assume it is, it would be a reasonable assumption that dry bites occur when the lower jaw of the snake has failed to gain a strong enough grip to cause the back muscles of the upper jaw to apply sufficient pressure on the gland and hence, force venom through the delivery system and into the victim/prey.

So in saying that it can be further assumed that dry bites may happen when a snake "snaps" in a defensive or instinctive action rather than delivering a bite where the intention is a deliberate act to inject venom and immobilize the prey or assumed threat.

George.

My only contradiction to this is from experience with my denisonia devisi. I was tagged with just one fang, with her mouth still partially open, and envenomation occured. Luckily, her venom isn't strong enough to cause anything more then slight swelling at the site. So some species may infact need to apply substantial pressure to cause a "wet bite."

Saying that, as stated before the mechanism of envenomation could vary rather substantially from species to species.

- - - Updated - - -

I checked online to find some sources that could help with this topic. I came across one article that states that certain species (such as a rattlesnake) can change their envenomation "strategies" depending on the prey items. It also states that spitting cobras - shown with diagrams - are able to change the way the project their venom.

I'm not sure if that mean they are consciously able to change the way they envenomate prey, or not envenomate prey altogether; nonetheless it's still an interesting read that makes you wonder.

Physiology of Snake Venom - Venom Delivery

 

[GBWhite]

What are the points that distinguish venom from saliva.

The compounds that make up venom are primarily proteins and polypeptides and various other substances with toxic properties. Saliva is 99.5% water with the other .05% consisting of mucus, enzymes electrolytes, glycoproteins and antibacteria.

Barrett,

I can only assume that considering the devis is only a reasonable small snake with a small venom gland and also considering the mouth was partially closed. It it must have been closed enough to provide sufficient purchase off the bottom jaw to apply enough pressure from the top jaw on the venom gland to force venom out and along the delivery system.

George.

 

[andynic07]

The compounds that make up venom are primarily proteins and polypeptides and various other substances with toxic properties. Saliva is 99.5% water with the other .05% consisting of mucus, enzymes electrolytes, glycoproteins and antibacteria.

Barrett,

I can only assume that considering the devis is only a reasonable small snake with a small venom gland and also considering the mouth was partially closed. It it must have been closed enough to provide sufficient purchase off the bottom jaw to apply enough pressure from the top jaw on the venom gland to force venom out and along the delivery system.

George.

I have just googled human saliva and enzymes are proteins and saliva also has polypeptides. Maybe it is just the strength that varies and is the difference?

 

[longqi]

Saw scale vipers use venom against humans almost 100% of the time
King cobras rarely use venom against humans -+10%
Most pit vipers can inject venom from a fang going beside the lower jaw with mouth still nearly closed
Gabboons have been known to bite straight through their own bottom jaw to inject venom

So although using the bottom jaw may help with delivery of larger quantities of venom IMO they can pick and choose