# Why do most poisonous animals tend to be cold-blooded? **URL:** \ **Category:** Factual Questions\ **Created:** [September 13, 2004, 3:40am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212 "2004-09-13T03:40:23Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [September 14, 2004, 3:13am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/21 "2004-09-14T03:13:59Z")
> [@](#): > > Batesian mimicry? Defensive displays are found in most snakes throughout the world. To suggest that such displays are the result of Batesian mimcry borders on absurd. Well rather than asserting that perhaps you can support it with some references? Are there any non-venomous snakes inhabiting areas without venomous snakes that use it? > [@](#): > > Many predators, most of the birds and some of the mammals such as the coyotes simply run up or swoop down and grab the snake by the spine, killing it quickly. Well we won’t get bogged down in the details. The point is that you conclude that many predators don’t strike without warning. That is all that is required for defensive venom to have a massive evolutionary advantage. That particular argument can now be scrapped since every snake in the world apparently has at leats one predtaor that doesn’t strike without warning. > [@](#): > > I was referring to situations where a predator has actually physically taken a snake. When a Coyote has a snake in it’s teeth, the snake has little chance of survival. An exaggeration, but very little of one. Well then can we have a reference to support it please? > [@](#): > > I don’t understand what you are trying to imply here. I’m not trying to imply anything. I am pointing out that if venom were to act as a major deterrent as you described it we would expect the non-venomous snakes to either become extinct or else to evolve methods to counter balance it. Those are the only two options. You can’t have a situation in the natural world where two direct competitor species are subject to massively different predation rates and both survive which is what you implied should happen. [quote] The evolution of predation defenses is an “evolutionary arms race” between the predator and the prey to continually “out-evolve” the other. This balances in the end due to the fact that neither ever gets to far ahead of the other. [quote] And yet you have suggested that “venom” as a “defensive advantage” would result in “the rates of predation of venomous snakes” being “significantly lower”. Why would it be significantly lower unless the prey species were significantly ahead of the predator? ---
**Author:** ![Ilsa\_Lund](https://avatars.discourse-cdn.com/v4/letter/i/a6a055/32.png) [@Ilsa\_Lund](https://boards.straightdope.com/u/Ilsa_Lund)\ **Post date:** [September 14, 2004, 3:53am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/22 "2004-09-14T03:53:50Z")
> [@Blake](#): > > Well rather than asserting that perhaps you can support it with some references? Are there any non-venomous snakes inhabiting areas without venomous snakes that use it? A nonvenomous snake whose entire range is completely outside the range of any venomous snake? I can’t think of any snake off the top of my head that meet that criterion, let alone the type of their defensive display. Nearly all snakes utilize some kind of defensive display when cornered, and venom is “only” 60 milllion years old. What do you suppose snakes did before that? The fact that the trait is as cosmopolitan as it is suggests that it is rooted farther back in the evolution of snakes than than the advent of venom, and suggestsing that all nonvenomous snakes are mimicking venomous snakes is slightly ridiculous, akin to suggesting that possums mimic badgers when they are cornered. > [@](#): > > Well then can we have a reference to support it please? A reference that a snake being held in the grip of a coyote’s jaws will likely die? I’m afraid I don’t have one. > [@](#): > > I’m not trying to imply anything. I am pointing out that if venom were to act as a major deterrent as you described it we would expect the non-venomous snakes to either become extinct or else to evolve methods to counter balance it. Those are the only two options. You can’t have a situation in the natural world where two direct competitor species are subject to massively different predation rates and both survive which is what you implied should happen. I still don’t understand. I’m saying venom doesn’t act as a major deterrent; that venomous and nonvenomous snakes are subject to roughly equivalent forces of predation when they occupy similar niches. Cottonmouths and water snakes in the southeastern United States are similarly sized, have very similar habitats and are often found syntopically, and have similar diets. They are also equally preyed upon equally by alligators, snapping turtles, hawks, etc. > [@](#): > > And yet you have suggested that “venom” as a “defensive advantage” would result in “the rates of predation of venomous snakes” being “significantly lower”. Why would it be significantly lower unless the prey species were significantly ahead of the predator? I’m saying that if venom were a significant defensive advantage, venomous snakes would be at the top of the food chain in much the same way that a tiger has no predators other than man because of its advantages of size, strength and lethality. Yet, venomous snakes are preyed upon; no less, apparently, because of their venom; indicating to me that venom does not confer a significant defense. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 14, 2004, 4:48am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/23 "2004-09-14T04:48:23Z")
> [@](#): > > I was referring to situations where a predator has actually physically taken a snake. When a Coyote has a snake in it’s teeth, the snake has little chance of survival. An exaggeration, but very little of one. I can accept that. But unless the coyote is gripping the snake very near to its (the snake’s) head, wouldn’t the snake have a pretty good chance of killing the coyote, too? I know that if I had poisonous fangs, and a predator had me in its jaws and my death were certain, I’d try to bite and inject it. Yeah, the snake still dies, but that’s one coyote who’s inclined to nosh on snake who’s been removed from the gene pool, so at least I’ll make the world a slightly safer place for my offspring and other relatives. And for the record, the plural of “mongoose” is “polygoose”. ---
**Author:** ![Ilsa\_Lund](https://avatars.discourse-cdn.com/v4/letter/i/a6a055/32.png) [@Ilsa\_Lund](https://boards.straightdope.com/u/Ilsa_Lund)\ **Post date:** [September 14, 2004, 5:18am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/24 "2004-09-14T05:18:33Z")
> [@Chronos](#): > > I can accept that. But unless the coyote is gripping the snake very near to its (the snake’s) head, wouldn’t the snake have a pretty good chance of killing the coyote, too? I know that if I had poisonous fangs, and a predator had me in its jaws and my death were certain, I’d try to bite and inject it. Yeah, the snake still dies, but that’s one coyote who’s inclined to nosh on snake who’s been removed from the gene pool, so at least I’ll make the world a slightly safer place for my offspring and other relatives. > > And for the record, the plural of “mongoose” is “polygoose”. Sure. It probably happens occasionally. But remember, this is a skilled predator, so the likelihood of a strike being possible are probably low and the coyote won’t _necessarily_ die. Additionally, as **Blake** pointed out, if the snake has not been quickly dispatched it will have been exhausted and likely incapacitated before being eaten. If you’ve never seen a video of a large predator like an alligator or a coyote eating a snake, they grab it and shake it violently while biting hard. Lather, rinse, repeat until the animal can be safely consumed. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [September 14, 2004, 6:28am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/25 "2004-09-14T06:28:45Z")
> [@](#): > > A nonvenomous snake whose entire range is completely outside the range of any venomous snake? I can’t think of any snake off the top of my head that meet that criterion, let alone the type of their defensive display. So there is no reason at all to assume it’s not essentially Batesian mimmicry. > [@](#): > > A reference that a snake being held in the grip of a coyote’s jaws will likely die? Not specifically, simply a reference that a snake will lose an encounter with most predators most of the time. Since you don’t have that your statement doesn’t make a lot of sense. Monarch butterflies lose most encounters with most predators that get a good grip on them, are you proposing that monarch poison offers no defensive advantage? > [@](#): > > I still don’t understand. I’m saying venom doesn’t act as a major deterrent; that venomous and nonvenomous snakes are subject to roughly equivalent forces of predation when they occupy similar niches. And I’m pointing out that your any claim that if venom worked as deterrent venomous snakes would be preyed upon much less doesn’t hold true. It could only possibly hold true if the non-venomous snakes were unable to evolve alternative defensive methods, in which case they would becomes extinct. Just so we can discuss this sensibly, will you accept that a wildebeest has a defensive advantage over a springbok because of its size? > [@](#): > > And for the record, the plural of “mongoose” is “polygoose”. Not according to any dictionary I’ve ever seen. I assume that was a joke. ---
**Author:** ![Ilsa\_Lund](https://avatars.discourse-cdn.com/v4/letter/i/a6a055/32.png) [@Ilsa\_Lund](https://boards.straightdope.com/u/Ilsa_Lund)\ **Post date:** [September 14, 2004, 7:46am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/26 "2004-09-14T07:46:28Z")
> [@Blake](#): > > So there is no reason at all to assume it’s not essentially Batesian mimmicry. Other than the fact that it is absurd to assume that nearly every nonvenomous snake on the planet of every conceivable phylogenetic stripe is essentially imitating a venomous snake when it puts on a defensive display. When a robin begins thrashing wildly and screaming when someone approaches its nest, it is not imitating a Killdeer. It is a common behavior in birds. > [@](#): > > Not specifically, simply a reference that a snake will lose an encounter with most predators most of the time. Not most of the time period, most of the time when the predator actually has physically grasped the snake with the intent of killing it. > [@](#): > > And I’m pointing out that your any claim that if venom worked as deterrent venomous snakes would be preyed upon much less doesn’t hold true. It could only possibly hold true if the non-venomous snakes were unable to evolve alternative defensive methods, in which case they would becomes extinct. OK, I understand your point now. Yes, I will concede that a wildebeest’s size gives it an advantage, _in terms of size_. The nonvenomous snakes would only go extinct when there were nonvenomous snakes in the same niche to being with, however. This is sometimes the case, sometimes not. The cottonmouth has nonvenomous analogues. The copperhead, throughout most of it’s range, doesn’t. If venom were a deterrent, then yes, either water snakes would go extinct or continue evolving new defense mechanisms. However, we would still expect _overall_ predation rates to differ markedly between the copperhead and the corn snake (snakes that are sympatric, but not in competition). Put another way, cheetahs and springboks are similar in size. Why are the predation rates by lions significantly higher on springboks than on cheetahs? Yet, many birds eat spiders and grasshoppers with the same gusto. If venom is a predatory deterrent, it is a very poor one indeed. The predation on animals with specialized defences is usually restricted to specialized predators. Yet snakes, both venomous and nonvenomous, are the prey of some of the most generalized predators in existence. ---
**Author:** ![Dijon\_Warlock](https://avatars.discourse-cdn.com/v4/letter/d/a9a28c/32.png) [@Dijon\_Warlock](https://boards.straightdope.com/u/Dijon_Warlock)\ **Post date:** [September 14, 2004, 10:33am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/27 "2004-09-14T10:33:49Z")
PBS here recently had a show on venemous animals (perhaps what inspired this thread?), and they mentioned that there are only four known venomous mammals. Of course, they mentioned the platypus (as someone did upthread there aways). Anybody know what the other three are? ---
**Author:** ![Ilsa\_Lund](https://avatars.discourse-cdn.com/v4/letter/i/a6a055/32.png) [@Ilsa\_Lund](https://boards.straightdope.com/u/Ilsa_Lund)\ **Post date:** [September 14, 2004, 10:38am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/28 "2004-09-14T10:38:10Z")
> [@Dijon Warlock](#): > > PBS here recently had a show on venemous animals (perhaps what inspired this thread?), and they mentioned that there are only four known venomous mammals. > > Of course, they mentioned the platypus (as someone did upthread there aways). > > Anybody know what the other three are? The echidna (Australian spiny anteater), the short tailed shrew and the European water shrew. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 14, 2004, 10:48am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/29 "2004-09-14T10:48:43Z")
> [@Incubus](#): > > I have to disagree. Why else does a snake need venom so potent that one bite could kill hundreds of mice? It only needs to kill one. Because that way, it kills mice _really fast_, reducing the distance they can run away before they drop and increasing the chance that the snake will get to eat them. In many cases, the venom is also the beginning of the digestive process too. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [September 14, 2004, 11:27am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/30 "2004-09-14T11:27:59Z")
Minor correction: > [@](#): > > The only venomous lizards are the Gila Monster and the Bearded Lizard. The [Gila Monster](http://wc.pima.edu/Bfiero/tucsonecology/animals/rept_gimo.htm) is not what I would call conspicuously colored. Same goes for the [Bearded Lizard](http://owen.nhm.ac.uk/piclib/www/comp.php?img=87577&cat=2&frm=med). The _bearded_ lizard linked is the friendly (if not quite cuddly) Bearded Dragon (_Pogona_) of Australia, found in homes and pet shops throughout the U.S. (and, presumably, Australia). The [Mexican _Beaded_ Lizard](http://www.survivaliq.com/survival/poisonous-snakes-and-lizards-mexican-beaded-lizard.htm) is a venomous lizard of Western North America. (The linked site uses the sloppy terminology of referring to these snakes and lizards as poisonous.) (Several sites mention that the Beaded Lizard and Gila Monster are the only venomous lizards. Interestingly, they tend to support my founder effect hypothesis: they are both in the genus _Heloderma_; they have adjacent ranges; they have nearly identical eating habits; both store fat in their tails; and they both use venom defensively.) ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [September 14, 2004, 11:30am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/31 "2004-09-14T11:30:26Z")
> [@Incubus](#): > > I have to disagree. Why else does a snake need venom so potent that one bite could kill hundreds of mice? It only needs to kill one. There are some extremely poisonous spiders whose venom is pretty much overkill. A cone shell is another example- this critter eats little fish, yet the same amount of venom in a person will kill them in a matter of minutes! > > Animals can recognize other animals that are poisonous, and avoid them. Mimicry is commonly used to mimic animals which are _poisonous_. So I would say an animal that had venom/poison has a defensive advantage, whether it is for that indiviual, or that species. Its hard to compare venom from landborne vs water borne animals. The aquatic venom has to be stronger, partly, because of dilution. Also prey has to be subdued immediately or it would be lost, as food, but still dead. The hunter would be eliminating its food source, and not eating. A downward spiral. Slight hijack: There’s an australian mouse, mole, vole, rat, anyway, some sort of rodent that’s poisonous. Is it like the Komoto Dragons? or does it have true venom? ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [September 14, 2004, 12:28pm UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/32 "2004-09-14T12:28:30Z")
> [@Ilsa\_Lund](#): > > The echidna (Australian spiny anteater) No that’s not right. Males of both the Tachyglossus (Australian) and Zaglossus (New Guinea) echidnas share the male platypus’ spur and gland, but the echidna glands are non-functional. Only the male platypus has a functional venom gland. ---
**Author:** ![aegypt](https://avatars.discourse-cdn.com/v4/letter/a/76d3ee/32.png) [@aegypt](https://boards.straightdope.com/u/aegypt)\ **Post date:** [September 14, 2004, 12:51pm UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/33 "2004-09-14T12:51:00Z")
Some shrews have venomous saliva. The slow loris of south-east Asia is poisonous. It’s a monkey. Well, a prosimian, technically. [More.](http://www.kingsnake.com/toxinology/loris/slow_loris.html) The liver of polar bears is poisonous. Though probably not their primary defense against predators. 🙂 I’d also like to mention that there’s only a single species of poisonous bird in the world, the “oil bird” of Papua, New Guinea. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [September 14, 2004, 5:18pm UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/34 "2004-09-14T17:18:25Z")
> [@tomndebb](#): > > Minor correction:The _bearded_ lizard linked is the friendly (if not quite cuddly) Bearded Dragon (_Pogona_) of Australia, found in homes and pet shops throughout the U.S. (and, presumably, Australia). D’oh! You are correct. I inserted an “r” where it didn’t need to be, then looked up the wrong photo. That’ll teach me to do searches on common names… Doesn’t really change what I said, though: given their environment, they still aren’t “stand-out” conspicuous the way many poisonous frogs and insects are. > [@aegypt](#): > > I’d also like to mention that there’s only a single species of poisonous bird in the world, the “oil bird” of Papua, New Guinea. Nope. Of pitohuis alone, there are at least four species, and there’s a whole other genus - _Ifrita_ - which is toxic. It is also believed that the toxicity of these birds is not inherited, but most likely acquired via diet. See [this article](http://nationalzoo.si.edu/Publications/ZooGoer/2001/2/intoxnewguineabirds.cfm) (originally posted by **Colibri** in [this thread](http://boards.straightdope.com/sdmb/showthread.php?t=274818)). In fact, there appear to be several other bird species which use some sort of noxious chemical as a defense, as noted in that article: > [@](#): > > Recent studies have suggested that many birds may be using some kind of chemical weaponry as defense, much like insects and amphibians. Ocean-going fulmars spit noxious stomach oils to drive away predators, some species of grackle give off a terrible odor when threatened, and many passerine birds, of which pitohuis and ifrita are members, have been known to smear their feathers with ants, apparently to repel parasites. Some birds, like the Eurasian quail (_Coturnix coturnix cortunix_), the spur-winged goose (_Plectropterus gambensis_) and the African olive-pigeon (_Columba arquatrix_), are suspected of being toxic as a result of eating poisonous insects and plants [see “Quailing from Quail”]. Two species of Australian bronzewing (_Phaps_ sp.) may even be sequestering the lethal toxin fluroacetate, more commonly known as “1080,” a poison that occurs naturally in their diet of heartleaf (_Gastrolobium bilobum_). But no one knew exactly which chemicals were being used. > > “The pitohuis and the ifrita are the first examples of birds that use an identified toxin as part of their defense strategy,” says Cornell chemical ecologist Thomas Eisner. “That discovery changed everything about how we think about birds.” ---
**Author:** ![Algernon](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Algernon](https://boards.straightdope.com/u/Algernon)\ **Post date:** [September 14, 2004, 10:20pm UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/35 "2004-09-14T22:20:10Z")
Very interesting discussion. But this made my day: > [@Chronos](#): > > And for the record, the plural of “mongoose” is “polygoose”. > [@Blake](#): > > I assume that was a joke. Heh, heh. A very good joke indeed. (I visualize Chico Marx talking about a “monogoose”) ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [September 14, 2004, 10:53pm UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/36 "2004-09-14T22:53:09Z")
> [@](#): > > Other than the fact that it is absurd to assume that nearly every nonvenomous snake on the planet of every conceivable phylogenetic stripe is essentially imitating a venomous snake when it puts on a defensive display. No it isn’t absurd in the least. If venomous snakes put on a display that deters predation precisely because they are venomous and since we have agreed that all non-venomous snakes hare habitat with venomous then it would in fact be absurd to suggest that it didn’t happen. > [@](#): > > Not most of the time period, most of the time when the predator actually has physically grasped the snake with the intent of killing it. Two simple questions Isla: 1. Do monarch butterflies use their poison as an effective defence? 2. Do monarchs lose an encounter with predators most of the time when the predator actually has physically grasped the butterfly with the intent of killing it? Once you’ve answered those questions I think it will be easy to show the flaw in your reasoning re snakes. > [@](#): > > However, we would still expect overall predation rates to differ markedly between the copperhead and the corn snake (snakes that are sympatric, but not in competition). Why? We don’t expect overall predation rates to differ markedly between the springbok and the wildebeest after all. > [@](#): > > Put another way, cheetahs and springboks are similar in size. Why are the predation rates by lions significantly higher on springboks than on cheetahs? Because there are far more springboks simply because there will, in any ecosystem, be more primary than secondary consumers. I don’t believe that lions do kill significantly more springboks than cheetahs relative to their abundance despite the differing defences of the species. And the same applies to venomous and non-venomous snakes. Relative to abundance the predation rate is the same. > [@](#): > > The predation on animals with specialized defences is usually restricted to specialized predators. Simply not true. A chameleon has a specialised defence and is preyed upon by every suitably sized generic predator in that environment. The same is true of a sloth or an opossum or a platypus or a skunk, all of which have specialised defences. There is no specialised skunk predator or specialised chameleon predator. This seems suspiciously like a circular argument. The predation on animals with specialized defences is usually restricted to specialized predators and we know when a defence is specialised because it restricts predation to specialised predators. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [September 15, 2004, 3:04am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/37 "2004-09-15T03:04:19Z")
> [@Darwin's Finch](#): > > Doesn’t really change what I said, though Agreed. It was a _minor_ correction. (In memory of our Chrysophylax, I couldn’t let a _Pogona vitticeps_ stand in for a Mexican Beaded Lizard.) ---
**Author:** ![Dijon\_Warlock](https://avatars.discourse-cdn.com/v4/letter/d/a9a28c/32.png) [@Dijon\_Warlock](https://boards.straightdope.com/u/Dijon_Warlock)\ **Post date:** [September 15, 2004, 8:35am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/38 "2004-09-15T08:35:48Z")
The three besides the platypus: > [@](#): > > _Originally posted by **Ilsa\_lund:** _ > > The echidna (Australian spiny anteater), the short tailed shrew and the European water shrew. > [@](#): > > _Originally posted by **Desmostylus:** _ > > No that’s not right. Males of both the Tachyglossus (Australian) and Zaglossus (New Guinea) echidnas share the male platypus’ spur and gland, but the echidna glands are non-functional. Only the male platypus has a functional venom gland. I found the fourth one, then: [The Solenodon](http://animaldiversity.ummz.umich.edu/site/accounts/information/Solenodon_paradoxus.html). > [@](#): > > Its heads is large in proportion to its body and the rostrum is elongated. A defining characteristic of Solenodon paradoxus is the os proboscis, a bone (which supports a long cartilaginous snout) located on the tip of the rostrum. This species’ dental formula is 3/3, 1/1, 3/3, 3/3 = 40. **The second lower incisor has a groove from which a venom is secreted from a mandibular gland.** So there we go. Shrew-like, only bigger (length average 1.02 feet). Never heard of that one. ---
**Author:** ![aegypt](https://avatars.discourse-cdn.com/v4/letter/a/76d3ee/32.png) [@aegypt](https://boards.straightdope.com/u/aegypt)\ **Post date:** [September 15, 2004, 8:48am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/39 "2004-09-15T08:48:48Z")
> [@DarwinsFinch](#): > > Nope. Of pitohuis alone, there are at least four species, and there’s a whole other genus - _Ifrita_ - which is toxic. Wow, really? Shows what I know about birds. And that I should stop posting things I hear in bars as facts. It makes sense that birds have an easier time evolving venom glands. Being more closely related to dinosaurs and other reptiles. Or are they? What’s also amazing is how people find out about these things. I mean, which sane person travels the jungle eating his way through the local bird fauna in order to see which ones are poisonous? “Choke, gargle, choke. I found another one, hooray! What a great day for science! Choke, gargle!” If that’s indeed how it’s done. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [September 15, 2004, 9:09am UTC](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212/40 "2004-09-15T09:09:35Z")
These birds don’t have venom glands though. As we sorted out above venom is something that’s injected. These birds are simply poisonous if eaten, although there is some evidence that their bites may be mildy venomous as well. What these birds have are slightly modified oil glands that secrete poisons that the birds eat. You know how when you eat a lot of garlic your skin can smell of garlic for days afterwards as the ‘oils’ are secreted in through the sweat glands? Well these birds do basically the same thing except the skin secretes the poisons form the insects and frogs the birds eat. Birds aren’t more closely related to dinos, they are a type of dino if that’s how you want to think of them. If you don’t then they are simply descendants of dinosaurs in much the same way that we are descendants of reptile like ancestors. Their closest living relatives are the crocodiles. However that’s all fairly irrelevant since: 1. Jurassic Park aside there is no evidence for any venomous dinosaurs. 2. Even amongst the reptiles poison isn’t really very common as we discussed above. It’s not as though simply being a reptile predisposes an animals to evolving venom/poison. [Previous page](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212.md?page=1) [Next page](https://boards.straightdope.com/t/why-do-most-poisonous-animals-tend-to-be-cold-blooded/264212.md?page=3)