Reptile & Amphibian Forums

Sorry to ask so many questions, but this seems to be the best place to get an intellegent answer. This time the question is "Why do some snakes inject more then enough venom needed to kill their prey? Is it because they lack control as to the amount? Unable to determined how much is needed? I base this question on observations over the years. I had in the past seen fairly large Canebreaks strike and seem to barely touch a small mouse with its fangs. The mouse lasted maybe 20 seconds. Other times the same snake would really clamp down after striking the same size mouse and then that mouse would last only a few seconds. I always assumed that a larger amount was injected. If that is correct, that is why I ask the question. Thank you for any response.

There are two things to keep in mind. The first is that the mouse is not its native prey item. mg/kg ratio, a squirell would likely be much more resistent than a white lab mouse. Second, the ultimate goal for venom is not to kill but rather kill quickly. That way the prey item has less chance to injure the snake or flee to die somewhere where the snake can't find it or where an opportunistic predator could get an easy meal.

Cheers
BGF
Venom & Toxin Database

Thanks for the answer. If I understand it, the snake will on different ocassions inject more or less based on circumstances. Thank you again.

One other thing to consider in the scenarios you laid out: the possibility that in the case of the snake grasping the mouse & holding, that the fangs, having gone deeper, may have punctured the heart or other vital organ, causing a more rapid death.

~~Greg~~

Good point. Thank you. Like I said, this is the place to ask.

Snakes will strike prey items that are too big for them to eat. They strike dead animals. They'll strike inanimate objecs that smell like prey. I once had a yearling boa constrictor that attempted to eat the sports section that was lining the bottom of his cage.

I think maybe you're giving snakes too much credit as far as being able to judge how much venom to use.

Thank you. Interesting, however, it brings up the question of dry bites. Does the snake intentionally not inject venom or is it just an uncontroled action? Thank you.

>>I think maybe you're giving snakes too much credit as far as being able to judge how much venom to use.

Actually, there is good experimental evidence that at least some snakes (rattelrs) adjust the quantity of venom injected in a predatory bite to the size of the prey animal: large prey get more venom than small prey.

In the case of defensive bites, there is far more variance, i.e., there are no hard and fast rules, which explains the huge variability in the level of severity from snake bites, from dry to massive envenoming.

Cheers,

Wolfgang
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WW

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Thank you for the response. I kind of thought that was the case.