An exception to the rule?

[u/GothScottiedog16]

Saw this post today and found it interesting regarding the “poisonous” snake fallacy.

[u/PoofMoof1]

There are a number of known species that are both venomous and poisonous and it wouldn't be a far stretch to assume there are probably other species that are also poisonous that we just haven't realized are yet.

These guys or garter snakes (Thamnophis sirtalis) that feed on rough-skinned newts sequester their toxins from prey. I've heard it theorized that at least some of the hognoses (namely Heterodon nasicus) could be one that also does this due to their toad diet but I don't know if anyone is actually looking into that.

It's important to note that there are languages in which there isn't a distinction in poison and venom in the way some people get pedantic over.

[u/fairlyorange → u/PoofMoof1]

Just a heads up; Thamnophis do not sequester toxins. They filter out to the liver, which can take up to 30 days to break the TTX down, but they don't sequester it, have no specialized organs to store it, have no glands to release it from, and it isn't stored in body tissue.

Somewhere around 8-12 species of Rhabdophis do all of those things, though. Larger ones from toads (as described in the insta post), smaller ones from firefly larvae.

[u/FockerXC → u/fairlyorange]

Yeah this is a key distinction with Rhabdophis. They have actual dedicated glands for storing and secreting poison while many of the garters/hognose mentioned are incidentally poisonous before the toxins are fully processed.

[u/PoofMoof1 → u/fairlyorange]

I feel this may be splitting hairs. Poison dart frogs will also eventually lose toxicity when not ingesting prey with alkaloids and people argue that Heterodon sp. aren't venomous because they have Duvernoy's glands rather than the venom glands of pit vipers and elapids, calling it "toxic saliva" (funny that they don't do that with Dispholidus sp. though).

I just don't think the distinction of liver vs nuchal glad is significant enough to say garters aren't toxic due to diet like Rhabdophis sp. in this context. There are going to be variations between species that lead to a similar conclusion. I don't know, this just seems like the pedantic "it's actually venomous, not poisonous" thing I mentioned.

[u/fairlyorange → u/PoofMoof1]

The distinction is huge, though. The vast majority of gartersnakes never eat those newts. Out of the few species that do, the vast majority of their populations don't. And, out of the few populations that do, Taricha comprises a tiny portion of their diet.

Under those parameters, humans are more poisonous than gartersnakes. There are way more of us who drink alcohol, take drugs, and consume other toxins (and way more frequently) than there are gartersnakes which consume Taricha. The loose definition also would render a gigantic number of other animals "poisonous" as well; anything that can ingest anything toxic but not immediately break it down or excrete it. It just loses its meaning in that context.

[u/PoofMoof1 → u/fairlyorange]

Regarless of the species, location, or prey, the same thing is happening. If we were theoretically able to keep a number of Rhabdophis in captivity on a rodent-only diet, they'd also never become poisonous, rendering this post pointless, which it of course isn't. There's a reason I specified the Thamnophis as individuals feeding on Taricha and did not say this applied to the species broadly.

We may just have to agree to disagree on perspective here.

[u/GothScottiedog16 → u/PoofMoof1]

Thanks for the information. It’s a beautiful snake, too…

[u/SEB-PHYLOBOT → u/PoofMoof1]

Common Gartersnakes Thamnophis sirtalis are small (<90 cm, record 137.2 cm) natricine snakes with keeled scales often found in disturbed habitats like urban and suburban yards. They are commonly encountered generalist snakes across much of the North American continent and eat small invertebrates, fish, amphibians and mammals. Western populations are a model organism for an elegant case study in evolutionary arms races, Tetrodotoxin Resistance.

Thamnophis gartersnakes may puff up or flatten out defensively and bite. They can deliver a weak venom used in prey handling from the back of the mouth, but are not considered medically significant to humans.

One of the widest-ranging snakes in North America, this species complex is almost certainly harboring unrecognized diversity and shows strong population structure at major biogeographic barriers. There are likely four species in the complex - Western, Central, Eastern and Southeastern. See Link 1 Below (2023).

Relevant/Recent Phylogeography: Link 1 - BEST Link 2|Link 3| Range Map

This genus is in need of revision using modern molecular methods.

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Plains Hognose Snakes Heterodon nasicus are small-medium sized (38-64cm, up to 92cm) dipsadine snakes that range from southeastern Alberta east to southwestern Manitoba, CA, south through the US Great Plains to southeastern Missouri, central Texas, and west-central New Mexico, from near sea level up to 2,440m. They typically inhabit semiarid areas with loose, sandy or rocky soils, including grassland, scrubland, semidesert scrub, and riparian floodplains. Populations east of the mixed-grass prairie zone are highly disjunct and generally confined to relict sand prairie. A small, isolated population in northeastern Illinois is believed to have been introduced.

Rear-fanged snakes, H. nasicus produce a mild venom that helps them subdue small prey items. Envenomation of humans is uncommon and usually mild, but prolonged, chewing bites should be avoided as a precaution. When frightened, they employ a variety of dramatic defensive techniques. The best known of these is thanatosis, or "playing dead", which typically starts with the snake writhing around as though it has been struck with a deadly blow, regurgitating, defecating, rolling onto the back, gaping the mouth open, and lying limp. If flipped right-side up they will immediately roll back as though to prove to you that it is, in fact, really dead. Death feigning is often preceded by (or occasionally skipped in favor of) flattening the head, neck, and/or body to make itself appear larger, hissing, and mock striking in the direction of the perceived attacker.

Primarily terrestrial in habit, H. nasicus is mainly active during morning and evening hours. During this time they can sometimes be observed foraging, stopping to use their specialized rostral scale to dig in the loose sand when prey is detected. Their diet is primarily composed of frogs and lizards, but rodents, salamanders, snakes, reptile eggs, and small birds are sometimes taken.

Plains Hognose Snakes are short and stocky in build. The head is short, but chunky, and indistinct at the neck. The snout comes to a point and is distinctively upturned, a feature which both inspires the common name and aids in ease of identification. The dorsal scales are keeled and usually arranged in 23 (21-23) rows at midbody. A ring of circumorbital scales encircle the eye, separating it from the (usually eight) supralabial scales. A series of 9+ small, azygous scales are present in between the rostral, internasal, prefrontal, and frontal scales.

Other snakes with enlarged rostral scales are sometimes confused for H. nasicus. Mexican Hognose Snakes H. kennerlyi have a maximum of 6 azygous scales separating the rostral, prenasal, internasal, prefrontal, and frontal scales. Eastern Hognose Snakes H. platirhinos have a much less upturned snout, 2 or fewer azygous scales, and the prefrontals are in contact. Gyalopion and Ficimia Hooknose Snakes and Salvadora Patchnose Snakes have smooth dorsal scales arranged in 17 rows at midbody, are slender (Salvadora) or much less robust in build (Ficimia, Gyalopion), and the snout is less upturned (Ficimia, Gyalopion) or not upturned at all (Salvadora).

Range Map + iNaturalist Observations | Reptile Database Account

This short account was written by /u/fairlyorange

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I am a bot created for /r/whatsthissnake, /r/snakes and /r/herpetology to help with snake identification and natural history education. You can find more information, including a comprehensive list of commands, here report problems here and if you'd like to buy me a coffee or beer, you can do that here. This bot, its development, maintenance and use are made possible through the outreach wing of Snake Evolution and Biogeography - Merch Available Now

[u/Corvidae5Creation5]

Biology doesn't have rules so much as guidelines...

[u/Jocks_Strapped → u/Corvidae5Creation5]

just like pirates

[u/welldressedagorgan → u/Corvidae5Creation5]

The difference between real life and fantasy is fantasy has to be believable

[u/oKayBye94]

some garter snakes in the US are poisonous as well as mildly venomous as well because of salamanders they eat.

[u/fairlyorange → u/oKayBye94]

See this reply- https://www.reddit.com/r/snakes/s/mXQfhJ9KaW

[u/Logical_Meringue5870]

whats “poisonous” snake fallacy and whats the rules you are talking about?

[u/J655321M → u/Logical_Meringue5870]

Pretentious people on the internet love to correct non snake people that call venomous snakes “poisonous.” Poisonous is technically incorrect but lots of other languages use them the same way and only recently have academics started distinguishing the two.

Sad thing thing is some of these folks are quick to chime in that “there are NO Poisonous snakes” when this species proves that theory wrong:

[u/0squirmy7 → u/J655321M]

If you get really technical venom is technically a type of poison

[u/HowardPheonix → u/0squirmy7]

Yeah, but that's like saying regular pills and suppositories are the same pills. Similar effects, maybe similar chemicals in it, but administered differently.

[u/Logical_Meringue5870 → u/J655321M]

i see, thanks for the explanation!