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From my layman understanding, animals that inject venom into the bloodstream by biting or poking are venomous. And ones that harm you when you eat them are poisonous.

Are there any animals (or plants) that fit both descriptions?

I'm guessing eating a venomous rattlesnake will give you an upset stomach but not cause enough damage to be classified as poisonous. And I'm pretty sure poisonous tree frogs don't bite into their prey and inject them with anything.

Stephen S
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    Any stomach upset from eating rattlesnake is likely to be purely psychosomatic. – jamesqf Nov 21 '16 at 06:04
  • What is poisonous depends on who (what species) is eating it, so you might want to specify if you are specifically interested in animals that are poisonous to humans. – fileunderwater Nov 21 '16 at 09:23
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    Anecdotally, people consume the venom sac of cobras in cognac. Apparently this causes some mild hallucinations (and if you happen to have a cut where it enters your bloodstream before the venom is neutralized by your stomach acids, it kills you) – Wayne Werner Nov 21 '16 at 13:35
  • Eating rattlesnake is pretty common. They're not at all poisonous. – Don Branson Nov 21 '16 at 22:13
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    @WayneWerner - ...and now, across America, thousands of idiots will start raising cobras for their venom sacs...which should, predictably and in short order, raise the average intelligence of Americans. – Bob Jarvis - Слава Україні Nov 22 '16 at 17:55
  • If a poison kills you through the bloodstream but not through digestion, it means that it was digested, nothing more. Rattlesnake venom is a protein that denatures in the stomach long before it reaches the bloodstream - it's not really different from eating any other kind of protein. Others may be destroyed through cooking through the same basic mechanism. Contrast this to e.g. alkaloids, which pass through the stomach unhindered. – Luaan Nov 23 '16 at 09:07
  • The amazonian giant centipede has a venom that is injects with bites, but it also exudes a poison that really will only give you a rash but i believe is classified as a poison. – Aaron Davis Oct 10 '18 at 19:16

2 Answers2

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That is certainly an interesting question!

First, to clarify definitions:

To be considered venomous the toxic substance must be produced in specialized glands or tissue. Often these are associated with some delivery apparatus (fangs, stinger, etc.), but not necessarily.

To be poisonous, the toxins must be produced in non-specialized tissues and are only toxic after ingestion.

Interestingly, many venoms are not poisonous if ingested.[1]

I know of at least three species that produce both poison and venom. One is a snake (although not a rattlesnake, which are, in fact, edible): Rhabdophis tigrinus, which accumulates toxins in its tissues, but also delivers venom via fangs.[2] The other two are frogs: Corythomantis greeningi and Aparasphenodon brunoi, which have spines on their snout that they use to deliver the venom.[3]

[1] Meier and White (eds.). 1995. Handbook of clinical toxicology of animal venoms and poisons. Boca Raton, Fla.: CRC Press, 477p.

[2] Hutchinson et al. 2007. Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus. PNAS 104(7): 2265-2270.

[3] Jared et al. 2015. Venomous frogs use heads as weapons. Current Biology 25, 2166-2170.

et is
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    Interesting, I got different answers when I asked for the difference between "poison" and "venom" on english.SE. – svick Nov 21 '16 at 17:24
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    But not too surprising. Try asking the definition of significant on english.SE and Cross Validated and see how disparate the answers can be. English.SE is concerned with general parlance, whereas, biology.SE is (generally) more concerned with the technical conventions. That is a good object lesson that definitions are only definite within a field. – et is Nov 21 '16 at 17:31
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    Can you please add links to your sources? I don't know if the book is available on Google books or some other resource, but the two journal articles will be available via PubMed. This will very much help people who want to check your claims, as well as those who wish to learn more. If Wikipedia articles (or some other better resource) are available for the animals you mention, you should link to them as well. – MattDMo Nov 21 '16 at 18:00
  • @svick Most of the answers to your question cite no sources. Interestingly, those that do actually align quite nicely with this answer. – talrnu Nov 21 '16 at 18:09
  • The answers in english.SE are not that different... Still, of course there is a difference between scientific use and regular use. But I would call it difference in the details. – BioGeo Nov 21 '16 at 20:27
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    @MattDMo I've added links. Luckily, Meier and White (1995) is available on Google (it is also available at any library with inter-library loan service). I think you'll find the claim you are wanting to check on page 3, first sentence. – et is Nov 22 '16 at 01:57
  • Your definition of poison seems rather narrow. I don't think poison frogs would meet it as stated. – CodesInChaos Nov 22 '16 at 12:05
  • @CodesInChaos Can you explain why you don't think Dendrobatids conform to the definition. – et is Nov 22 '16 at 14:10
  • Although it fits the question, isn't "To be poisonous, the toxins must be produced in non-specialized tissues and are only toxic after ingestion." a bit narrow? After all there are animals (like some frogs and toads, as well as many insects) - as well as some plants (poison ivy) - that are poisonous to the touch (causes rash and maybe allergic reaction) or have poisons (often on the skin) that start working as soon as they're in your moth (so you spit it out). These are not venom, since it's not injected into the blood... but nor are they toxic in the sense that the poison must be ingested. – Baard Kopperud Nov 22 '16 at 19:59
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    @BaardKopperud, I think you are coming at this question from too anthropocentric a viewpoint. Organisms may produce topical reactions in human skin, but it is unlikely, in most cases, that this was the selective impetus for developing that chemical. They probably evolved those toxins in response to predation, and the topical reaction of hair-less apes (recent new comers in most cases) is just collateral effect. Also, there are plenty of things that taste bad (e.g. sour citrus, spicy peppers, bitter greens) that evoke a taste aversion response, but are harmless to ingest (so, not poisonous). – et is Nov 23 '16 at 04:59
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I once read something about a type of tiger snake that was poisonous to touch and has a venomous bite.

Edit: I found the species Asian Tiger Snake, Rhabdophis Tigrinus

Rattlesnake meat is the same as any snake just don't eat the head.

Ash359
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