We all remember the classic children’s fable in which a princess kisses a Golden Dart Frog and, while she waits for it to transform into a handsome prince, her heart begins to flutter, and eventually she realizes it’s not a good flutter at all but really a very serious ventricular fibrillation induced by a potent neuro/cardio toxin. Then she immediately falls over, dead.
The moral of the story, of course, is that you should never ever touch – let alone make out with – an extremely poisonous amphibian. Especially the Golden Dart Frog (Phyllobates terribilis, Lit. ‘A terribly embarrassing death by frog’). It’s estimated that of the 150-175 known species of dart frogs indigenous to Central and South America, all of which are poisonous to varying degrees, the Golden Dart Frog of Columbia is far and away the most lethal. It is, by many accounts, the most toxic animal on this planet and single-handedly accounts for Columbia’s shamefully high PMR (Princess Mortality Rate).
‘Can I turn into a handsome prince? Maybe I can, maybe I can’t. Why don’t you come over here and kiss me and we’ll find out together.’
If the scientific name P. terribilis and the fact that it’s an evil yellow frog aren’t enough to deter oral contact, then perhaps some sobering biochemistry will. When disturbed, the Golden Dart Frog secretes a ghastly powerful alkaloid batrachotoxin – from glands on its back and behind its ears – with the chemical formula C32 H42N2O6 and a molecular mass of 538.67 g mol -1.
But no need to concern yourself with the technical stuff. All you really need to know is that this organic molecule acts specifically on voltage-gated sodium channels by increasing the permeability of sodium cations, which in turn irreversibly depolarizes the cell membranes that the Na+ channels serve, effectively blocking neuromuscular transmissions1, which is an obvious problem when it comes time to oh, say, live and breath and the like. Indeed, the entire mechanism is remarkably simple:
See there? You learn something new every day.
In short, if the frog’s alkaloid batrachotoxin finds its way into an animal’s bloodstream (via a miniscule cut on your hands, for instance) it will completely shut down the peripheral nervous system and lead to cardiac arrest. One frog carries enough toxin to kill 100 people, so obviously, it doesn’t take much to kill one. You could probably hide a lethal dose of the Golden Dart Frog’s poison under a couple grains of sand2. Stated in less engaging scientific terms, a mere 136 micrograms in the bloodstream will kill someone who weighs 150 pounds. If you want to kill someone who weighs 96 pounds or 223 pounds or some non-multiple/divisor of 150, or a European who reports their weight in kilograms, you’ll have to set up the stoichiometric equations yourself.3
Dart frogs are so named because Amerindians in Central and South America’s rainforests are famous for using their toxins on the tips of blow darts. They catch the frog, hassle it, and then proceed to rub their darts all over the frog’s backside (by this time just absolutely glistening with death). Thus armed, they head out into the jungle, load the blowpipe, and recite the warrior’s creed of, ‘Dude. Seriously. Be really, really careful where you point that thing.’ (This is a good time to remind Animal Review readers that one should never eat a monkey dispatched by a Columbian Amerindian. It’s supposedly safe to digest the Golden Dart Frog’s toxin after it’s been cycled through an animal, but better to be safe than sorry. Stick with the plantains.)
By now you’ve most likely heard enough and, if you’re like most people, you definitely want a Golden Dart Frog for the terrarium in your living room. Sadly, this is dumb but doable. Dart frogs raised in captivity do not produce the alkaloid batrachotoxin, because this ability is entirely diet dependent. It was recently discovered that the Golden Dart Frog feeds on a beetle that gorges itself on poisonous plants. The beetle accumulates the toxin and posthumously passes it up the food chain to the dart frog. If denied these insects, Golden Dart Frogs will eventually lose their toxicity. But this process may take years, so the wild-harvested Golden Dart Frog is recommended only for that special kind of weirdo hobbyist who doesn’t mind a very real risk of killing the cat, the maid, the neighbors, the neighbors’ kids, his or her kids, his or her frog-curious friends and loving parents, the landlord, the cable guy, the phone guy, the TV repairman and/or him/herself.
‘Do I still secrete a deadly neuro/cardio toxin? Maybe I do, maybe I don’t. Why don’t you try cleaning this terrarium and we’ll find out together.’
Be that as it may, the innocuous-looking-but-deadly Golden Dart Frog is headed towards an excellent mark. Animal Review is more than willing to award a grade of A to any animal that can instantly kill whatever eats/kisses/touches it, out of awe of Mother Nature (and also fear). However, there is a snake called Liophis epinephelus that has somehow developed immunity to the Golden Dart Frog’s poisonous wares, and so the Golden Dart Frog is regularly reminded that DNA mutation is a double-edged sword.
1 Discussion question: Sodium ion channels are also present in the nerve and muscle cells of the Golden Dart Frog. So why does it not succumb to its own toxin? (The answer is upside down at the bottom of this page. Nah, we’re just messing with you. The frog evolved sodium ion channels that aren’t affected by the alkaloid batrachotoxin.)
2 But that would be weird.
3 It is beyond boring. We don’t want to know about it. Just keep your units straight and that’s all we have to say on the matter.