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Hank faces off against his Crash Course co-worker Evelyn from the Internets in this test of wits and sticky science knowledge! Who will win and who will lose? Watch to find out! And find more of Evelyn over on Crash Course Business:

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Cockroaches and Coffee

Beards and Microbes

Red Triangle Slug

Fecal Shields

Sea Hare Opaline

Bleeding Fungi

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 (00:00) to (02:00)

We'd like to thank the sponsor for today's show,  Brilliant has a variety of courses you can take to brush up on math and science, something that would have probably helped our contestants prepare for today's competition.


Michael: Welcome to SciShow Quiz Show, where the points don't matter, but the science does.  I'm Michael Aranda, your host.  Let's see who's playing today.  Our first contestant is Evelyn from The Internets, who you may know from the internets?

Evelyn: Yes.

Hank: I also live there.  

M: Or because she's the awesome host of Crash Course Business.  Evelyn, can you tell us a bit more about that?  

E: Yeah, so Crash Course Business, I'm hosting 17 episodes, and I'm talking about soft skills, so things about job searching, things about negotiation, practical tips to beast in the workplace.

H: Like, hello, like--

E: Communication, yeah.

H: Can we test to my handshake.  That's a good one, I like it.  

E: Yes.

M: Evelyn will be facing off against Hank Green, who many of you know from the internets, although lately people seem to be talking a lot about his dead tree publication.

H: I did put, I did kill a bunch of trees for a book, but I also, I don't host Crash Course Business.  I wanted that gig, but I got kicked out.

E: His loss.  

M: Our contestants will be battling for intangible bragging rights, but also some very tangible prizes, which will go to two Patrons from Patreon that we've selected at random.  Evelyn.

E: Yes?

M: You're competing on behalf of Julia Pederson.

E: I got you, Julia.

M: And Hank, you're playing for Anne Foster.

H: Hi, Anne.  

M: Each of you begin with 1,000 SciShow points.  Answer a question correctly and that number goes up.  Answer it incorrectly, that number goes down.  Whoever emerges from the last round with the most points wins their Patron some slick gear.  Stefan, what can they win today?

Stefan: Anne and Julia, come on down.  Welcome to the prize compound.  Don't go anywhere, don't close your eyes.

 (02:00) to (04:00)

Who will win?  I won't spoil the surprise, but you'll both receive cards from our final round, autographed cards.  How does that sound?  If you secure the win, you'll get the 'I Won' pin which will help you seal the good feel within, and of course, the secret SciShow swag will go to the winner, don't forget that.  But even if you end up with less points, hopefully the 'I Lost' pin will not disappoint.  Alright, enough of this rhyme.  I'm done, I suppose.  I guess it is time to go back to the show.

M: Thanks, Stefan.  Without further ado, let's start our first round.  Since both of you know so much about business, this round is all about workplace hazards.  

E: Oh, okay.

M: Entomologists, the scientists that study insects, spiders, and such, have some special, unique workplace hazards, like being bitten or stung by venomous things, but one particular hazard makes their job really difficult, because they spend so much time with the animals they study, they can actually become allergic to them.  It's hard enough to conduct research when the organism you study can send you into anaphylaxis, but the researchers that study cockroaches have also reported a particularly annoying complication from developing an allergy to their study's species.  

E&H: Ew.

H: Ok, great.

M: They found they're also allergic to which of the following?

H: Oh my God.

M: Paper, coffee, cheese, or red meat?

H: Okay.  Can we--I'm--you're about to go, but I just want to say, one, you have to live with cockroaches all the time.  Two, you suddenly become allergic to something else?  Okay, you can go.  Hit it.  You did it.

E: Okay.  Um, I was just gonna guess.

H: Yeah, I don't know the answer to this.

E: Let's give it a smooth red meat.  

M: I'm afraid that is incorrect.

H: Ohh, okay, I guess I have to do the thing now and go ahead and say, paper seems unlikely.  

 (04:00) to (06:00)

There's a lot of stuff in coffee.  Maybe there's some coffee-cockroach crossover.

E: That's disgusting.

M: That is correct.

H: Ehhh!  You're drinking cockroaches!

O: The answer is B, coffee.  Developing allergies to your study species is often an unfortunate side effect of working with a particular type of organism for years and years.  According to studies, a substantial portion of people who work with lab animals develop allergies to them, so in that sense, it's not surprising that entomologists that study cockroaches often complain that their otherwise harmless study species become a threat to their health, but to add insult to injury, that often means they become allergic to their favorite cup of joe, too.  Pre-ground coffee in particular masks the presence of any bugs that infested the beans or fell into the machinery, and as gross as it might sound that there might be cockroaches in your coffee, it's really okay.  Regulatory agencies like the US FDA allow a certain amount of what they call 'insect filth'.  For coffee beans in the US, up to 10% can be infested or contain insect parts, but what's really interesting is why that limit exists.  The FDA's reasoning is simple: aesthetics.  Truth is, you could have many more cockroaches in your coffee and you'd be fine, healthwise.  You just might actually realize they're there.  

M: Question two: microbiologists and doctors have to be especially careful to avoid exposure to potentially dangerous pathogens.  That's not just for their own health.  They might carry things around which can infect other people who come in contact with them, and doctors, especially surgeons, routinely come in contact with people who are highly susceptible to infections.  That's why medical personnel have some of the strictest safety protocols around, but preventing infection doesn't always mean complicated containment protocols or restrictive protective gear.  Studies support a rather simple way to reduce the risk of spreading pathogens.  All you have to do is--

H: Okay, A.

M: Work naked, shave, wear nail polish, or wear chapstick?  

 (06:00) to (08:00)

H: I just--decreasing surface area, work naked.  There's less stuff to cling to.  

E: That's another hazard.  That's another type of hazard.

M: I'm afraid you are incorrect.

H: That was--okay.  

M: I like where your head's at, but.  

E: I'm gonna say shave.

M: That is correct.  

H: That's also decreasing surface area but in a way more boring way.  Do they know for sure that it doesn't help?  I feel like it would.  

O: The answer is B, shave.  Hospitals and microbiology laboratories are always trying to find ways to minimize the risk of infection, and though it might sound like a silly question, whether beards pose a problem for microbiologists and doctors has been the focus of a surprising number of studies, because I guess people are really attached to their facial hair.  The problem is, those chin whiskers can harbor bacteria even after they're washed thoroughly, and studies seem to suggest they're especially good at harboring some of the more dangerous infections.  Beards can also make those surgical masks less effective.  One study found that bearded doctors shed significantly more bacteria from the bottom of the masks than those without, so if you want to make sure you don't spread bacteria, staying clean-shaven is a simple and straightforward step, though generally not a mandatory one, and no, going naked generally won't help.  Your skin has plenty of pathogenic organisms already on it, and it's totally capable of carrying things around, which is why surgeons don disposable protective gear in the first place.

M: Let's see how our contestants are doing.  You're both tied at 1100 points.  For our next round, we're gonna talk about some real slimy characters.  The red traingle slug is a large species of land slug from Eastern Australia named for its noticable markings.  

H: Its red triangles.

M: They would make tasty meals for the tree frogs they share their forested home with, but scientists have discovered that they have a potent weapon that helps keep them safe, a special kind of slime.  

 (08:00) to (10:00)

Specifically, they secrete red tinted slime from their backs which does what: makes the slugs too slick to grab onto, instantly paralyzes the frogs, glues wet frogs in place for days, or smells like dead frogs?

E: Fascinating.

H: Ooh, that would be a good one.  I'll let you go first.  Get rid of one of these options for me.

E: Fascinating.  Nature's cool.  I'm going to say makes it smell like dead frogs.

H: I was gonna go with dead frogs, too.

M: That is incorrect, I'm afraid.

H: See, that's why you go first.  Um, I'm gonna say it sticks the frogs in place.  They get stuck.

M: That's correct.

H: Ehh!  That's weird.

O: The answer is C, glues wet frogs in place for days.  While you might not think a red triangle slug looks terribly appetizing, lots of animals do, but the slugs don't go down without a fight.  It turns out they secrete a defensive mucus which is basically frog superglue.  Scientists happened to be conducting fieldwork at night in a forest in New South Wales, Australia when they stumbled upon a branch with a rather stuck red eyed green tree frog a mere centimeter away from a definitely not stuck slug.  They watched the pair for ten minutes and when the frog failed to free itself, they decided to take both animals back to the lab for further study.  The frog remained stuck to its twig for 48 hours and even once it was free, it kept sticking to things because its body was covered in a reddish mucus.  That mucus, the researchers learned, was secreted by the slug, but it's distinct from the slimes it uses to get around.  To get the slug to make more, the researchers just had to poke at it.  Interestingly, the sticky slime only became stickier when water was added, which is why it was able to glue the slippery frog in place.  The researchers don't know what makes the slime so sticky, but they're hopeful that studying it further could lead to new adhesives that still work in wet conditions.

 (10:00) to (12:00)

M: Like slugs, baby beetles are tasty treats for hungry predators, so unsurprisingly, beetle larvae have all sorts of defensive adaptations to avoid becoming someone's lunch.  Perhaps the grossest, though, are the slimy shields that the larvae of shining leaf beetles lug around.

H: The slimy whats?

M: Many members of the subfamily (?~10:22) carry wet masses on their backs as an anti-predator defense.

H: Wet masses?

M: What do they keep inside these gooey backpacks?  

H: (?~10:34)

M: Their own feces?

E: Oh, God.

M: A gross-smelling oil, a toxic fungus, or shed exoskeletons?

H: Oh my God.  Nature's terrible.  I'm gonna say they keep their poop in there.  Ehh!

M: You are correct.

E: Wow.

H: They keep their poop in there!

M: Poop is always the answer.  

E: When in doubt.

H: I mean, you got a bunch around.  You might as well put it in your mucus backpack.

O: The answer is A, their own feces.  Shining leaf beetle larva are one of lots of beetles that use a fecal shield in defense.  We've talked about the hard fecal shells of tortoise beetles before on SciShow, but shining leaf beetles make much gooier versions, and it turns out storing poo in a slime backpack lets the larva use their meals' defenses as their own.  Their backpacks are made from their own poop, or frass, and mucus, and that poop isn't just there for bulk.  It contains potent toxins which seem to come from the animal's diet.  Studies have shown these shields only work when the larva eat toxic plants.  Though the toxins aren't the exact same, the beetle modifies the stuff it eats before piling it into its slime shield.  This all works because the beetles have evolved a resistance to some of the most potent plant toxins and some researchers think their ability to resist noxious chemicals is a big part of why they're so successful as a group.  There are about 1400 species of shining leaf beetle.  It's also part of what makes them annoying agricultural pests.  Members of the slimy backpack club include notorious species like the cereal leaf beetle.

 (12:00) to (14:00)

M: Speaking of slimy defenses, sea hares get their name from the long sensory structures on their heads, which somewhat resemble rabbit ears.

H: Oh.  Sea hares.  

M: But they should probably be called sea slugs, because they're shell-less relatives of marine snails and because like land slugs, they know a thing or two about slime.  When scared, these animals can emit a purple-ish substance that's a mix of ink and slime called opaline, which helps them escape from predators.

H: Aw, that sounds awesome.  Are there any like, YouTube tutorials on how to make that stuff?  There's a lot of slime on this platform, I don't know if you guys have noticed.

M: In a 2013 study, researchers figured out how all this colorful goo keeps the animals from falling prey to hungry lobsters.  According to their work, is it that it acts like a smokescreen, it clogs gills, suffocating the attacker, it blocks the predators' sense of smell, or it mimics blood, attracting larger predators?

H: Ooh, clever.

E: That is--

H: You gonna take it?

E: Uh, I buzz first, think later, so let's think through this.  I'm gonna say it clogs their gills.  Clogs somebody else's gills.  Come on!  

H: Blood.  I'm gonna say it does the blood thing.  I'm also wrong.  All right.  

M: Ah, dang.

E: Sorry, Julia.

O: The answer is C, it blocks the predators' sense of smell.  Lots of animals use ink or slime to thwart would-be predators, but sea hares use a combo of the two and it wasn't immediately clear to scientists why they have both.  The hares make their ink and opaline slime in separate glands and they can just release one of the two.  The ink part makes the most sense, because most predators find it unpalatable, but opaline isn't thick enough to really suffocate an attacker like, say, hagfish slime does, and it doesn't seem to taste bad to predators either.

 (14:00) to (16:00)

It's kind of sticky, though, and researchers noticed that it seemed to induce grooming behaviors in predators, so researchers wondered if it might mess with the predators' senses.  When they painted opaline onto the sensory appendages of lobsters, the animals lost their appetite.  Further study revealed the sticky slime literally blocks the cells that sense chemicals in the water, basically plugging the lobster's nose and since they stopped smelling the tasty smells of food, the lobsters stop attacking the sea hare.  According to the researchers, it was the first known case of a prey species inactivating their predator's sensory system to avoid being eaten.

E: I feel like there are other ways, you know?  All that slime, there has to be something.  

M: I'm catching on to your strategy here.  I don't know if you know that you're doing this, but you're getting really excited about the wrong answers and then letting her buzz in and deliver those wrong answers.

H: Ooh, that one sounds very right.  

M: Well, that's it for all the slime.  Hank, you're at 1400.  900, I'm sorry.  It's time to place your bets for our final question.

H: Oh, wow, it's already, we're there.

E: So soon.  So soon.  

M: Based on your knowledge of bloody messes.  

H: This is not how it works.

M: In the meantime, all of you at home can enjoy this lovely word from our sponsor.

O: I think it's pretty clear from today's competition that we all could benefit from brushing up on our math and science knowledge, and there's nowhere better to do that than  Brilliant offers a variety of courses, quizzes, and problems to keep you on the top of your game.  You might want to try your hand at Brilliant's daily problems, for example.  Every day, they publish several daily problems that let you challenge your brain to gain a deeper understanding of math, logic, science, engineering, or computer science.  It will be like you're on your own SciShow Quiz Show, except you'll be playing against yourself.  You can check out today's daily problem at and right now, the first 200 people to sign up at that link will get 20% off the annual premium subscription, so you can view all of the daily problems in the archives and unlock dozens of problem-solving courses and in addition to having a great time and staying sharp, you'll also be supporting SciShow, so thank you.

 (16:00) to (18:00)

Now back to the action.

M: Alright, it all comes down to this.  Question six: if you visit the pine forests of the Pacific Northwest, you might stumble upon what some call a bleeding tooth fungus.

E: Oh no.

H: I've seen a picture of it.  It's real bad.

M: The young fruiting bodies are sometimes the shape and color of teeth and they can ooze a red goo.  

H: Sure.

M: Making them appear to literally bleed.  Coincidentally enough, this red goo contains a compound called atromentin which acts a lot like a component of actual blood.

H: Hmm, gross.  

M: Which of the following is true about atromentin?  A: A hemoglobin-like oxygen carrying pigment, B: A vasopressin-like hormone, C: A heparin-like anti-coagulant, or D: An albumin-like protein?  

E: You know, I would just like to apologize to my good friend Julia.

M: Whoever wrote this script, these are big words!  

H: He's having a hard day.  

M: Big words.

H: You're doing really good, Michael.

M: The words are really big.

H: I think I know the answer.  I don't.  I have no idea.  I made a guess, but the good news is I didn't risk any points, so I have a 1 in 4 chance of winning, basically.

M: You ready to reveal your answers?

H: Mhmm.

E: I guess.  

M: 3, 2, 1.  

H: C, we both went with C.  

E: C?

H: Yours looks much better than mine.  We were both right!  I lost!  

M: You were both correct.

O: The answer is C, a heparin-like anticoagulant.  Though these fungi might look like they're bleeding, what they're actually doing is exuding a sap-like substance in a process known as guttation.  It happens in both plants and fungi, though in most species, the fluid emitted is clear, so it's commonly mistaken for dew.  

 (18:00) to (19:56)

Scientists understand the basic mechanics of guttation in plants, but fungal guttation is kind of a mystery.  What we do know is that guttation fluid can contain all sorts of compounds.  Because of that, some think it might act as an herbicide to kill off neighboring species that are getting a bit too close or it might protect against hungry mouths or microbes, and that last possibility could explain the guttation of bleeding tooth fungi, as it includes a heparin-like anticoagulant called atromentin.  Atromentin is made in the fungal tissue of bleeding tooth fungi and its relatives, and it's also got antibiotic activities, but scientists have yet to test whether atromentin or the bloody goo in general actually protects these fungi against harmful microbes.  It's possible the red guttation is simply a way to get rid of excess water, one that happens to drag along some interesting compounds from within the fungs.

E: Julia!  Oh girl!  We won!  Oh God.  I said sorry.  I said sorry.  

M: Sorry for winning!

H: I can't bel--oh man.  I don't know what I was thinking.  I was like, oh, it's revolutionary.  I never thought to just not risk any points.

E: And I was like, I'm gonna risk almost everything so I still have a little bit of dignity left for me and Julia.

H: Right, yeah, you just wanted to have those 50 SciShow bucks.

M: If you want to see more of Evelyn and work on your business soft skills, be sure to check out Crash Course Business, which you can find over at  We'll link to the first episode about the foundation of everything business, building trust, in the description, and if you want to see more of Hank, well, he's here on SciShow all the time, so be sure to click that subscribe button.

H: I live here.  

M: Thanks for watching this episode of SciShow Quiz Show, and thanks to our sponsor,  Be sure to check out  

E: Bye.