Attack of the Zombie Parasites!


[MUSIC] Zombie stories like The Walking Dead, World
War Z, Night of the Living Dead are fun. Armies of clumsy, mindless, but surprisingly fast
armies of undead brain-eaters. “BRAAINS!” But could they actually exist? To find out,
you need to start looking for real world zombies. Or zom-BEES. If this tiny fly happens across a honeybee,
it hops on its back, stabs it in the gut, and injects its eggs. Kind of rude, really.
Those eggs will hatch into maggots that eat the bee from the inside out, but before the
bee dies, these wriggly passengers do something to their host’s brain. The bee starts to
move erratically, it flies out at night, just like a… zombie. That’s just one of dozens of strange parasites
in nature that seem to be able to turn unsuspecting creatures into half-dead, mind-controlled
puppets. Every once in a while, the odd worker ant
will drift from the beaten path, and blindly begin to climb the stalk of a plant. It walks
out on a leaf, bites down with its last ounce of strength, and dies. Soon after, the zombie
master bursts out of its sarcophagus, stalks of a fungus named cordyceps, raining spores
down below to infect the next passing ant. When it’s time to lay her eggs, the beautiful
emerald jewel wasp turns cockroaches into zombie midwives. When they first meet, the
wasp introduces itself by stinging the roach in the abdomen and temporarily paralyzing
it… then it goes to work like a neurosurgeon. The wasp probes its stinger into a specific
part of the roach’s brain, injecting chemicals that block the roach’s instinct to run away.
It’s not dead, not frozen, it just has no will to run. Now the wasp master can grab
the roach’s antennae and pull its new pet home like a cockroach cocker spaniel… where
it promptly lays eggs inside it so it can be eaten from within. One tiny worm infects crickets. It slowly
feeds on them from within, growing larger, and larger, and larger. When it’s time to
leave the “nest” these worm release chemicals that hijack the cricket’s nervous system,
and cause them to jump into the water and drown. The foot-long worm then wriggles out,
to breed in the water, and start the cycle all over again. Then there’s the tiny roundworm that turns
the abdomens of South American ants bright red and makes them stick their rear ends in
the air like tasty berries, perfect for birds to pluck up and go poop out elsewhere, delivering
the worm to new hosts. Not even plants are safe. This wild mustard
can be manipulated by a fungus to produce fake flowers, complete with fake nectar, which
trick bees into landing and transferring spores to new plants. These examples and lots more, are some of
nature’s creepiest biochemistry. What’s amazing is that even our fancy pharmaceuticals
don’t act as specifically as many parasites’ chemical cocktails do. The emerald wasp’s venom, for instance,
blocks receptors for one special neurotransmitter, and only in the neurons that would make the
cockroach run away. Nature’s parasites were doing neurobiology long before humans ever
picked up a medical textbook. And for parasite cases like those ripe, red
ants, evolution is acting on a whole group of animals, the worms, the ants, and the birds
that nibble on them. These elegantly evolved relationships are
everywhere in the world of zombie parasites, but perhaps none is weirder than the case
of the psychedelic zombie escargot. Let’s say a garden snail eats some bird
poo, which is already gross, but this poo is full of parasite eggs. These worm eggs
hatch inside the snail, living and feeding, and filling the snail’s eye stalks with
their babies. The zombie snail crawls out into broad daylight, its mind taken over,
eyes pulsing full of baby worms like some sort of horror film half-caterpillar, half-disco-ball.
Yum yum, and the cycle continues. Luckily that could never happen to us. Unless
you own a cat. The single-celled protozoa Toxoplasma gondii
can only sexually reproduce inside the intestines of a cat, but it can take up residence in
a variety of mammals. If it finds its way into the brain of a mouse, the rodent suddenly
wants to be friends with felines, like it’s under the spell a parasitic love potion, following
the smell of cat urine to its untimely demise. The Toxo undergoes sexual reproduction inside
the cat, gets dropped off in the litter box, and the cycle begins again. What’s weird is that as many as one in three
humans may be infected with Toxo. They aren’t offering themselves as dinner for cats or
anything, but some scientists think these people show personality differences, or are
more risky. “I just really love cats, and I just wanna
hug all of em, but I can’t, because that’s crazy, I can’t hug every cat.” That evidence is thin, but it makes you think.
Or maybe it makes the parasite think. SCREAM “Oh no!” So, could human zombies we see in movies actually
exist? Well… no. After we die, our bodies stop producing ATP,
and the protein machinery that moves our muscles is frozen in rigor mortis. And considering
that the trillions of bacteria in our intestines have to eat something, real zombies would
be less like the movies, and more like gooey statues. But if the complex neural machinery of mammals
can be overtaken by a simple, single-celled organism, what else is possible? Why don’t you exercise your free will, and
hit the subscribe button. Oh, and that tingling sensation in your brain is just the effect
of some awesome science, promise. Stay curious.

100 Replies to “Attack of the Zombie Parasites!”

  1. Hey, you should do a video behind the science of the Bermuda Triangle. By the way, these ideas are absolutely great.

  2. What about like in Viral? for the most part it seems pretty rational (until the weird hive/nest things at the ends.

  3. zombies might not exist, but considering the power of knowledge and what nature probably has in store for us, it might just be possible

  4. Shoot, I have a cat and I have a strange love for my cat. Like I just want to hug her so much sometimes. It's strange, in either lonely or infected.

  5. I probably have that cat-loving parasite, and I couldn't really care less. I have no problems with parasites that don't cause extreme problems. Besides, I've always liked cats.

  6. Hey, I making Zombie grasshopper almost exactly like this bug 1:30 –2:10 , I learn it by myself.

  7. I think that if Humans could be turned into Zombies it would either be from the Microbes in our bodies, or maybe new Strain of Rabies or and STD/STI, it would have to be readily Accessible, and or Easily Transmissible to us.

  8. Actually there could be a zombie apocalypse since the person doesn't have to be dead there could be a parasite that blocked nerves that give off pain ability to recognise people a lot of aggression and transmitted through saliva get rekt

  9. 30% of comments- zombie apocalypse theories.
    20% of comments- wow, I might have the cat-loving parasites!
    10% of comments- we need to kill all crazy, old cat ladies!
    10% of comments- I was eating while watching this…
    15% of comments- now I'm scared, but I want to get rid of my cat now…
    10% of comments- that snail thing was creepy.
    4% of comments- love your vids!!!
    1% of comments- random

  10. You say that zombies as we know them couldn't exist because once the body dies it stops producing needed chemicals, but who says the parasites couldn't just reanimate you and tell the body to start producing them again?

  11. Human zombies exist(ed)! It's just that our definition of "zombie" has changed. I was a little disappointed that you didn't mention the original definition of "zombie" actually referred to supposedly mind-controlled/suggested people, possibly given drugs in order to coerce them to labor on farms. Some white dude visiting Haiti wrote about it & it became a popular exaggerated trope in cinema in the 30s-40s, mixed with a lot of racist stuff about voodoo, but that original kind of zombie got supplanted when people later used the term for the Romero ones, even though he didn't use that term himself in Night.

  12. Well, at least these Zombie Parasites can't control us!

    Wait, Can They?

    A Parasite that gets inside the body by the mouth or feet and control us? Possible.

  13. The bad thing that t gondii can do is it Could cause spontaneous abortions in pregnant women which is why it's suggested pregnant women not change litter boxes. Aside from that, we're still not sure if it causes anything else like what it does with rodents.

  14. Oh, poor dear you. You still don't know that Free Will is an Illusion concocted up by our brains and environment.
    I'm not disputing that you have an identity, but it's a grand illusion.
    When analyzing our mind (back to the whole two brain hemispheres nut), I've come to realise that there is no singular identity.
    Sometimes I behave out of character, usually when parts of my body have been under a lot of pressure.
    Now this character is still me, but not the me I want to be.
    Depending on how stressed I am, my personality might actually be interpreted as that of a zombie.
    Things get even weirder, when you think about how much our bodies and moods are influenced by food, exercise, music and drugs.
    Even something like reading a comment will change your life in a completely different direction.
    No, don't think about it. That would make me win. 😉
    We humans are impulse driven. That is undeniable. But thanks to an echo of experiences, it allows us to learn, plan and train beyond our base natures.
    Damn we've successfully turned into a Bundle Theorist. :'(
    Hey, at least we can't go to hell. 😉

  15. You probably forgot to mention the most zombie-like virus that affects humans and animals. The rabies virus! It travels from the bite zone to the brain where it continues to multiply and changes your behaviour. Hosts show zombie-like symptoms like making strange sounds , being aggressive and biting as the virus load is in the saliva and that's how it can be transmitted. And to add to the similarities between the illness and Hollywood… It has no definite cure in advanced stages.

  16. Toxo is also in sheep. I get sick of poor cats getting the full blame. People are in more danger of getting toxo eating undercooked lamb, as it's pretty rare for a person to get cat chit on their hands to begin with and then not to clean them and then for toxo, even that would only be a problem when the cat concerned was infected. It lives in the flesh of the sheep continuously, though the sheep farming industry is pretty keen to keep the blame full on cats. I learned this when studying threatened species in Australia. Having evolved without toxo in the ecosystem here, it kills Eastern barred bandicoots, which have enough problems ot begin with; however they also only live in grasslands which are now sheep farms, so they have a fatal (to them) parasite in the sheep poo that's on the ground where they dig for food. Your CDC has a good fact sheet about it.

  17. Okay, so you guys are awesome, but I must say, this video was horrifying. Parasites — particularly worms — are a phobia of mine, and watching a huge worm work its way out of a host… ugh. Just ugh. It's my own fault for watching this right before bed, but still. Gross.

  18. What about the disease in 28 days later? It's symptoms look a lot like rabies, so that's probably as close to realistic as any zombie virus has ever gotten…

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