from Hacker News

The impossible predicament of the death newts

by bdr on 6/5/25, 1:40 PM with 183 comments

• by arp242 on 6/5/25, 2:01 PM

  > Meanwhile, evolving resistance also comes at a cost. We don’t know that directly, but we can infer it pretty well. If resistance to tetrodotoxin were cheap and easy, everything would evolve it. [..] We don’t know, but we’re pretty sure there must be something. We know that garter snakes outside of the Pacific Northwest are much less resistant to tetrodotoxin. They’ll drop dead from doses that their Oregon cousins simply ignore. So evolving the resistance must have some cost or drawback.

  I'm not so sure that's really the case; it's more that for many animals there simply isn't any pressure to evolve (or retain) this trait.

  It's not like the natural selection process has a feature list it can tick off. It operates with zero foresight and an incredibly dumb principle: whatever helps procreation.

  Cows are not dying due to tetrodotoxin poisoning in significant numbers, as far as I know, so there is no reason for them to evolve resistance to it. The same applies to most animals, including the snakes outside that area.

  Your dog can synthesise their own vitamin C and will never develop scurvy. Most animals can do this – humans and some other primates are the exception. An ancestor lost the trait for vitamin C synthesis by chance, and because these primates were living in trees eating lots of fruit with vitamin C, evolution simply didn't notice. There is no disadvantage to being able to synthesise vitamin C, and no advantage in dropping the trait. It didn't affect procreation (at the time). Now we're all stuck with it.

  Now, maybe all of this does have a cost for the snakes. But it's far from a given that there is one.

• by k__ on 6/5/25, 8:20 PM

  I recently learned, there is a dangerous plant in many gardens around the US. If you stand under it for more than 10minutes, you're pretty much dead.

  Turns out, it's the water-lily.

• by alkyon on 6/5/25, 5:53 PM

  The linked article about toxic blue-ringed octopus is even more interesting.

  https://crookedtimber.org/2025/03/14/occasional-paper-the-in...

• by atentaten on 6/5/25, 2:53 PM

  Interestingly written article. Raises some questions:

  >Newts with weaker poison? They get eaten. Snakes with less resistance? Have trouble finding newts they can choke down, and don’t get to steal their poison. So the arms race continues.

  How does a snake know that the Newt has weaker/strong poison? Is it leaving some Newts along and eating others, or is it eating any Newt it runs across? Does a strong-poison newt survive snake consumption attempts?

• by jakey_bakey on 6/5/25, 2:29 PM

  > Turns out there is an answer: the garter snakes sequester the tetrodotoxin, storing it in their livers. This makes them toxic to their own predators.

  Second-order effects are so cool

• by ednite on 6/5/25, 2:09 PM

  Love the title, and great article.

  This might be a total tangent, but every time I see “newts”, I think about how Karel Capek actually coined the word robot in his 1920 play R.U.R., and then later gave us War with the Newts...really smart amphibians. Thanks for sharing.

• by onlypassingthru on 6/5/25, 4:16 PM

  Apparently the snakes' immunity pales in comparison to the local caddisflies.

  [0]https://www.discovermagazine.com/planet-earth/a-beautiful-we...

• by titanomachy on 6/5/25, 3:06 PM

  Newt poisoning of humans must be rare, I’ve lived in this region my whole life and I don’t think I’ve ever heard of this!

• by water-data-dude on 6/5/25, 2:53 PM

  Oooooh! I saw “I’ll have to teal deer it” and thought it must be some strange idiom. Had to go to Urban Dictionary to find out “teal dear = tl;dr”, and now I feel as dim as a garter snake that’s evolved resistance to large amounts of tetrodotoxin.

• by rufus_foreman on 6/6/25, 2:03 AM

  They're cute. They're pretty much harmless in my experience.

  They swarm all over the PNW, in season. Don't step on them if you can help it. They're not death newts. I'd be a dead commenter if they were death newts.

  They swarm all over the trails in spring, and then they're gone for the rest of the season. That's my recollection of it.

  I don't live there anymore, maybe they have evolved into these dangerous death newts. One can hope.

• by UncleOxidant on 6/5/25, 5:30 PM

  > Turns out there is an answer: the garter snakes sequester the tetrodotoxin, storing it in their livers. This makes them toxic to their own predators.

  But this doesn't seem as immediate as the newt's defense where it's on the skin and thus causes potential predators to spit them out or even to seize up - meaning that at least some attacked newts survive the encounter. Eating the liver means the snake is dead. And since it's going to be impossible to tell if a particular snake is immune (and is thus potentially toxic) how would this deter predators? (Especially given the limited range of snakes with this immunity and the probability that there are predators of the snakes that don't necessarily have this same limited range - ravens, raptors, etc.)

• by steve_adams_86 on 6/5/25, 2:24 PM

  Christ, I handled these as a kid quite a bit. Add that to the list of reasons I will wonder how I survived past age 10.

  I used to keep native snakes and lizards (and inadvertently breed them!), and couldn’t keep newts because I wasn’t sophisticated enough to create the right environments for them. This is one species I kept (and killed, unfortunately). I’ve learned to do it far better since then, but haven’t tried keeping newts again. They’re beautiful little creatures.

• by ryukoposting on 6/6/25, 2:51 AM

  What a fun read! One side note: the coloration of that garter snake is very strange to my midwestern eyes. Our garter snakes aren't nearly as vibrant.

• by deadbabe on 6/5/25, 2:50 PM

  Could being a toxic or venemous creature be bad for survivability of a species in the long term if smarter creatures discover you’re lethal and thus become determined to kill your kind on sight?

• by SwtCyber on 6/6/25, 7:07 AM

  How even when we think we've figured it out the system throws in a curveball. Nature's like, "Oh, you thought this was simple? Cute."

• by brookst on 6/5/25, 1:54 PM

  Fascinating article and really enjoyably written.

  Though I remain a tiny bit disappointed that it wasn’t about some arcane royalty arrangement for the band “The Death Newts”.

• by smallnix on 6/5/25, 3:04 PM

  Mirror snapshot: https://archive.ph/hJHNM

• by pmarreck on 6/6/25, 2:32 PM

  I learned a new word: "aposematic"

  I can already think of uses of this word jokingly in a people context

• by kentrf on 6/5/25, 2:04 PM

  Fascinating and well written article!

• by CaffeineLD50 on 6/5/25, 5:53 PM

  I'm pretty sure my degoogled Murena /e/ OS pixel 5 won't have this problem.

• by mark-r on 6/6/25, 11:23 PM

  Don't snakes find their victims more by smell than sight? Do they even see in color? It seems that "don't eat me" coloration might work for the newts.

• by theospeak on 6/6/25, 1:35 AM

  What a fasinating read. Thoroughly enjoyable writing. Thank you.

• by juantxo93 on 6/5/25, 9:52 PM

  intersting

• by ryanblakeley on 6/5/25, 2:26 PM

  I once took a group of young people foraging for mushrooms in the Willamette valley on a farm that had loads of these newts. I warned every body not to touch them.

  After preparing dinner, one girl got very ill, as did I, while other people who ate the dinner were fine. I was so worried I'd mis-identified some mushrooms.

  But turns out she had handled one of these newts and the bacteria had transferred to the mushrooms she picked. I contacted it from washing the mushrooms. I threw up several times that night.

  In hindsight, had we not washed the mushrooms as thoroughly as we did, things could have gone much worse.