[MUSIC] Alex I'll take "Potent Potables" for $200 please. I may move slow, but my venom can kill
you in minutes. Joe What is a cone snail! That is correct. I'll take "Potent Potables" for $400 please Alex. Whether it’s Mortal Kombat or my venomous
tail, play against me and you could see a “fatality”. Joe again. What is a scorpion! Yes. "Potent Potables" for $600 Alex. [OPEN] Only a few of nature’s toxic avengers earn
the title of “venomous.” If a toxin has to be ingested, inhaled, or
absorbed, we call that animal poisonous, like these frogs. But venomous animals deliver it direct, usually
into a wound. Biting, stinging, stabbing, that sort of thing. We find venom all over the animal kingdom,
and there’s as many different venoms as there are venomous species. Animals with spines and stingers often use
venom for defense. Animals with toxic mouthparts or tentacles
tend to use their venom to hunt. Others use venom to eat or even to fight during
mating season… just when you thought the platypus couldn’t get any weirder. So what’s the most venomous animal? It’s tough to say. Scientists usually rank venoms using a number
called the “LD50”, the dose it takes to turn half of test animals from alive to…
no longer alive. The lower the LD50 the deadlier the venom. But most venoms didn’t evolve to target
lab mice, so that number doesn’t always tell the whole story. When we add in factors like how often people
are bitten or stung and how many actual deaths that animal causes… the winner for “deadliest”
is clear. Why’d it have to be snakes? Venomous snakes make some of nature’s most
deadly and complex chemical cocktails. They manufacture that venom using modified
saliva glands, and deliver it using hypodermic needles disguised as teeth. On paper, a soft, ectothermic noodle isn’t
the ideal predator, but with venom in their arsenal, snakes don’t have to outrun or
fight their prey. They just paralyze it with neurotoxins, or
let it bleed to death from the inside by injecting hemotoxins. Who needs legs when you’ve got chemistry? When toxinologist Bryan Fry mapped snake venom
genes onto an evolutionary tree, he found that snakes branched off from lizards about
100 million years ago, but their venom was even older. Venom is so biologically expensive that many
modern snakes have stopped making it, but the ancestor of all snakes was venomous. The earliest venom proteins were borrowed
from other parts of the body, where they did normal jobs, like control blood pressure or
how nerves work. If they were present in saliva, and happened
to kill prey faster, that species gained an advantage. As venoms became more toxic, evolution isolated
them in the mouth so snakes wouldn’t poison themselves, and they developed sophisticated
delivery methods. Venom genes across the animal kingdom are
some of the fastest-evolving genes we know of. Snakes are constantly changing up their formula
to stay one bite ahead of their prey developing resistance. Even though a cobra can take down an elephant,
to a honey badger, it looks like dinner, and several other snake-eating animals have figured
out venom immunity. Like honey badgers, mongooses and hedgehogs
have tiny mutations in the switches that control muscle contraction, so venoms that cause paralysis
don’t work on them. And the opossum is so awesome that one ingredient
from its blood can neutralize a wide variety of snake venoms. Scientists are studying it as a possible universal
anti-venom. Today, antivenoms are made by injecting nonlethal
doses of venom into a large animal. Its immune system goes to work dispatching
antibodies to inactivate the venom, the antibodies are purified from the blood, and we have an
anti-venom cocktail ready for some unlucky human. But a few people think we can train our own
immune systems to fight venom. Self-immunizers regularly inject small amounts
of venom into their own body, hopefully not enough to kill them, but enough to get their
antibody factories going. I shouldn’t have to say this, but DO NOT
try this at home. SI-ing sounds like a ticket to the Darwin
Awards if you ask me, but still, those who do it claim they can take lethal doses of
venom and walk away. Of all venomous animals, we seem to have a
special interest in snakes. Brain scans have shown that we can detect
snakes before we consciously see them, there’s even special neurons in primate brains that
only respond to images of snakes. The evolutionary pressure of not becoming
dinner for a hungry snake favored primates with more complex vision. More complex vision required larger, more
complex brains, and larger more complex brains are what set our ancestors down the path of
becoming us. Anthropologist Lynne Isbell calls this the
“Snake Detection Theory” of primate evolution. It’s certainly only part of the story of
our big brains, but to come down from the trees and bite into a world of knowledge,
maybe we just needed a little help from a snake. Stay curious.
