A to Z Challenge: K (poisons & stories of their use)

Kokoe poison frog

From: Wikipedia

Fast Facts:
– Also known as poison dart frog
– The frogs excrete the poison: batrachotoxin
– About 136 micro grams is a lethal dose
– One frog has about 1100 micro grams
– It affects nerve and muscle cells resulting in cardiac failure
– Believed to be the poison that killed navigator Ferdinand Magellan

When touched or threatened, poison dart frogs (found in the Amazon in South America) produce venom from glands behind their ears on their backs. Traditionally, indigenous people have used the venom for blow darts.

The poison, Batrachotoxin, is extremely toxic, with only 136 micro grams required for a lethal dose for a person weighing 68kg (or 150lb). That’s about the same as 2 grains of table salt. One frog has enough poison to kill an average human 8 to 10 times.

The toxin interferes with the nerve and muscle cells of the body, basically opening them so a lot of sodium ions flow into the cell, making the muscles contract and ultimately causing cardiac failure. There is no known cure. The frogs themselves have a modified sodium channel protein so the toxin can’t bind to a receptor.

What is fascinating, is that captive-born frogs are not poisonous, which suggests the poison comes from their diet. The food source has been determined as a beetle, but it was discovered by an incident on the other side of the world, in Papua New Guinea when it was discovered a Pitohui bird had the same toxin in its feathers (although not at the same strength). You can watch the short video below to hear that story (it’s really interesting and only goes for 1min 48sec).

It would be really rare for a beetle to synthesise a molecule like batrachotoxin, so it is thought they also get it from their diet, possibly arthropods or plants.

Batrachotoxin is thought to have been the cause of the death of Ferdinand Magellan (the Portuguese explorer who organised the Spanish expedition to the East Indies from 1519 to 1522, resulting in the first circumnavigation of the Earth, which was completed after his death). There was an attack with local tribal people in the Phillippines and Magellan was struck by a poisoned arrow and left to die by his retreating comrades.



22 comments on “A to Z Challenge: K (poisons & stories of their use)

  1. Giggling Fattie

    April 13, 2021 at 10:03 pm

    Ooooo so cool their poison comes from their diet!! Do you think if you took a poisonous wild frog and then took it into captivity, would it lose its toxicity? And how long before it does?! Intriguing!

    • Actually, they’ve don those sorts of experiments. I think they do lose some toxicity. And then any young they have are toxin free.

  2. I’ve heard of this one also. How is it that I know so much about poison? Hmm? Good summary,

    • Hmm, starting to worry about you, Jacqui 😉 I think you should be writing crime, not prehistoric fiction!

  3. Kinda scary, when you think about it, something that small being that deadly…

  4. What a fascinating post and the video was quite interesting as well.

    • How scary it must have been to suddenly find your mouth tingling and going numb (and probably scarier when you discovered the cause). I found it interesting to hear the experience from him personally.

  5. Another great post, and each of the toxins you mention reminds me of TV shows or films where these have been used.
    That’s fascinating about the bird in Papua New Guinea, isn’t nature amazing.

    • Nature constantly amazes me. We have a frog in Australia that burrows and hibernates underground until it rains (which in inland Australia can be years). When it rains it comes to the surface, breeds and then disappears again.

  6. I had no idea frogs bred in captivity aren’t poisonous! Crazy how that toxin works its way up the food chain!

    • Makes you wonder what else eats the beetle (or whatever they eat to get the toxin). There are probably other animals in the jungle which are also toxic.

  7. Truth is stranger than fiction and there is so much we still haven’t figured out. All of the research on this has been pretty recent, so we don’t really know that much. Who knows, maybe it will cause some huge breakthrough somewhere, someday.

    Maybe it is in an enzyme no one has noted yet, the rest of the world turned on enzymes.

    • Exactly! I know they are hoping it will make some sort of medical breakthrough, but they don’t know what sort of breakthrough because they don’t know enough about it. They’ve started researching and I guess time will tell.

  8. I wonder how far back one could trace the poison. Because if it isn’t the beetle, then where does it come from? Interesting.

    • I know! And it is so interesting that they don’t actually know where it comes from. I’m not sure if they are hunting for the source, but I can only imagine there must be some studies in that area happening.

  9. Same thinking than Liz, how far can we ckeck the origin of the poison? Frogs seem to have tamed their effects very well.

    • Apparently it is a freak mutation that lets them survive the poison. I wonder how long ago that happened?

  10. I hadn’t heard about the poisonous birds. Very cool. But I always wonder how the birds and the frogs eat the poisonous beetles without being poisoned themselves. Neat trick, and very useful.
    Black and White: K for Kitezh

    • Maybe the toxin is only present in very teeny amounts but builds up in the birds and frogs? Puzzling but fascinating.

  11. This is so intriguing. I did know about this poison, but not that frogs born in captivity don’t have it.

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