SciShow Tangents - Fear Month: Sharks!

Episode Date: October 8, 2019

SciShow Tangents' Month of Fear continues! This week, Stefan is confronted by his fear of sharks! Thrill as we weave a tale of nigh-immortal sharks! Feel the chills run down your spine as you learn about how weird shark penises are! Try not to scream when you hear about Sharkarado, the Shark Colorado! This episode... might be too scary!!!  Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! If you want to learn more about any of our main topics, check out these links:[Truth or Fail]Still Shark Eggshttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0052551Tiger Shark Siblingshttps://www.smithsonianmag.com/science-nature/baby-sand-tiger-sharks-devour-their-siblings-while-still-in-the-womb-46192985/Thermal Ventshttps://www.livescience.com/61699-skates-eggs-thermal-vents.html[Fact Off]White Shark Caféhttps://schmidtocean.org/cruise/voyage-white-shark-cafe/#datahttp://whitesharkcafe.org/media/photos-videoshttps://www.npr.org/sections/thetwo-way/2018/05/28/613394086/great-white-sharks-have-a-secret-cafe-and-they-led-scientists-right-to-ithttps://www.sfchronicle.com/news/article/Mysterious-great-white-shark-lair-discovered-in-13234068.phphttps://www.nature.com/articles/415035bGreenland sharks eating sealshttps://www.sciencedirect.com/science/article/pii/S0022098112001657?via%3Dihubhttps://animals.mom.me/seals-sleep-4736.htmlhttps://www.nationalgeographic.com/news/2012/6/120626-greenland-sharks-seals-sleeping-animals-science/[Ask the Science Couch]Intromittent organs/peniseshttps://academic.oup.com/icb/article/56/4/705/2198314https://www.sciencemag.org/news/2013/06/scienceshot-birds-disappearing-penisShark claspershttps://www.sciencemag.org/news/2015/04/how-shark-penises-evolvedhttps://www.nature.com/articles/ncomms7698https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/clasper[Butt One More Thing]Coprolite shark toothhttps://www.earthtouchnews.com/discoveries/fossils/that-time-a-prehistoric-shark-took-a-bite-out-of-a-turd/

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen. This week, as always, I'm joined by Stephen Chin. Stephen, what's your tagline? Sweet beef stew. Sam Schultz is also here. Oh, hello. What's your tagline?

Dracula's little son. S-O-N? Yeah, if it was the other one, he would explode. Sari Reilly, hi. Hello. What's your tagline? Am I safe for work? And I'm Hank Green, and my tagline is foot sweat.

Every week here on SciShow Tangents, we get together to try to one-up a maze and delight each other with science facts. We're playing for glory, and we're playing for Hank Bucks. Now, we do everything we can to stay on topic, by which I mean we don't really work very hard at that at all. It's called SciShow Tangents. But if we deem your tangent unworthy, then we can dock you a Hank Buck. So tangent with care. And since we are now entering the scariest and spookiest month of all, we're doing a thing. Each episode in October, we'll cover a topic that is one of our panelists' greatest fears.

Now, as always, we introduce this week's topic with the traditional science poem from Stefan. Is this your fear, Stefan? Yes. All right, I see how it's going to work. This is my fear submission. In the open ocean, there are many things I fear, but one stands above the rest. I think it's pretty clear.

Sharks. I'm scared. I'm not safe when they're near. Yes, I know the stats say I'm more likely to be killed by a deer. Even a coconut is technically more dangerous to me, but a coconut would just float harmlessly on the sea. So while a shark attack may in fact be pretty extreme, a shark can still come up behind you.

Dun-dun-dun-dun-dun-dun-dun-ing. A shark is a muscular, tooth-covered maw. If it weren't for the terror, I might feel the awe. They're ancient and beautiful, especially from a distance. And I know they are more threatened by our existence. So yes, I respect and admire these creatures despite their multiple unfair movie features, but still, when I look out onto the deep,

I can't help but feel that the ocean is not the place for me. Despite their multiple unfair movie features. Really great. I didn't believe that you were really scared of sharks, but after that poem, I do believe it. Yeah, sharks are scary. That's the fastest I've ever heard you talk in my entire life. He's really channeling something there.

Yeah, animals that are bigger than me, like bodybuilders, elephants. It's all human males. What about like a moose? Moose are terrifying. They're so scary. They're so scary. They're so big. It's like eight deer.

I was at Jerry Johnson Hot Springs and there was one that was like close. And I was like, do we need to go? I'm like shirtless in a hot spring and it's cold out there. And this like stranger in the hot spring with me said, poofs like razors. Oh my God. I'll never forget it. I'll never forget. I'll never forget. No, I hope not.

So our topic today is sharks, which I feel like is a pretty distinct branch of a phylogenetic tree and should be fairly easy to define. Am I correct? Yeah. Are they the only cartilaginous fish? No. Oh, what is he?

Skates, rays. I thought those were just sharks. They're fish? No. Oh, what is he? The skates, rays. I thought those were just sharks. They're not? No, they're a separate thing. Oh, okay. They're closely related to sharks. The shark thing, the interesting thing about it is that they branched off from bony fish really early on. All of the bony fish are very distantly related to sharks, which is really cool.

And also the thing that I love most about that is that it's not just they don't have bones. They don't have the same systems for making scales. So shark scales are made out of teeth. What? Like the same material of teeth. I love it. And their teeth have fluoride and stuff. And their scales have fluoride?

No, I don't think their scales have fluoride, but sharks' teeth have fluoride built into them. So there's no gingivitis. Why would they care? They get new ones all the time. They do get new ones all the time, but they just have all these adaptations to keep their teeth really healthy. Because without teeth... What is a shark without teeth? I don't know.

A gummy old fish. I mean, what's a whale shark without teeth? A whale shark. Doing just fine. So the split is at the class level. I think maybe super class, class, thereabouts. Osteic these is the bony fish, which makes sense because osteoblasts and osteocytes. Sounds like a bone word.

Yeah, our bone. We're osteic these too. Are we? Yeah. I mean, we are in that we are more closely related to bony fish than we are to sharks. But we're not in this class. But the ichthys part is edifice. We're not in the class. No, but we are. We're not. We're descended from bony fish than we are to sharks. But we're not in this class. But the ichthys part is the fish part. We're not in the class.

No, but we are descended from bony fish. One of our great grandpappies was an osteichthys. Yeah. There's this way of taxonomy where like you are whatever you are descended from

like dinosaurs and birds. Like you say like all birds are dinosaurs because they were descended from them and like we are in that way fish and that we are descended from fish.

Are birds also fish? Birds are also fish. All the bony land animals that's a scientific fact we're all each other we are all sponges you're a sponge i can only aspire to be a sponge the absorbency stefan just wants to be more absorbent which i understand when winter rolls around and lotion season arrives my skin is so dry I have to let everyone know that I've been docked one Hank Buck for a tangent you're not gonna hear about getting oily on a tarp everybody should lose one

let's do it let's all lose one everybody starts at negative one we just deeply screwed everything up for like 10 minutes and for future me. I'm sorry about the editing for the podcast, Sam. The other class is called chondric bees, which is where the cartilaginous fishes are. Sharks, rays, skates, sawfish.

The naming is interesting because chondrocytes are the cells that produce cartilage. And cartilage is the stuff that, I don't know, it's like in your nose. It gives it structure. It's on the ends of your bones to pad it. Like it's in your kneecap. Not as strong as bone, but stronger than some of the other structural stuff inside you.

How much more dangerous is a coconut than a shark? Do you have that off the top of your head? So the number that is cited is 150 people a year from coconuts. It's like six a year from sharks, something like that. But the coconut number is a little unverified. But some people do die from coconuts.

Right, yeah. But unclear how. Yeah, you shouldn't try to eat one whole. Okay, now we've got some holes to dig ourselves out of. It's time for Truth or Fail. I, Hank Green, have prepared three science facts, but only one of them is real. You've got to pick the real one. If you do, you get the Hank Buck.

If you don't, I get the Hank Buck. It's about sharks, which is convenient since that's what this episode is about. Sharks, as you may or may not know, have it all mixed up about how to have babies. Some of them do eggs and some of them do live births. Basically, they have eggs inside of them that hatch inside. But also they have eggs that they lay. And I've got three facts about shark eggs. And I want you to tell me which one is the true fact. Fact number one. Now, it's nice if you can pull it off to keep your eggs warm after you lay them. Like birds do this by sitting on the nest, but obviously this is hard if you're a fish. So Pacific sleeper sharks convert hydrothermal vents, these are deep-sea sharks, to their own

personal incubator. These sharks bury their eggs in areas near these deep-sea vents, which provide warmth and help speed up the egg development process. Or, fact number two, sand tiger sharks turn to egg raiding for their very first meal after they hatch. Female sand tiger sharks will deposit their eggs strategically near the eggs of various other prey. And when freshly hatched from their eggs, sibling baby sand tiger sharks will team up and dine on those eggs, taking advantage of their nutrients and ensuring their own survival. Or, fact number three, bamboo shark eggs were able to track the presence. So the embryos inside of the bamboo shark eggs were able to track the presence of potential predators using electroreceptors.

When they detect a threat, the shark embryos freeze inside the egg. They just stop moving so that their movement won't give away their potential location to predators. Is a bamboo shark real? A bamboo shark is real. But I think I would have lied to you just now if that's a lie, but I did choose all real sharks. Is a bamboo shark real? I have no idea. I believe Hank that yes.

I don't know. People just name sharks whatever they want. Shark and bamboo would never come even close to each other, I would imagine, under normal circumstances. Maybe it looks like a green stick, and they're like, oh, it's that piece of bamboo floating in the water. Oh no, that's a shark. That's kind of the situation. They're sort of striped like bamboo, and have like segments.

The second one sounds kind of mundane to me. How is that mundane? I don't know. I agree. It sounds like some other animal. How is that mundane? I don't know. I agree. It sounds real, but boring. Like, it's a different thing that does that. You're eating other babies. Well, a lot of stuff eats babies.

Babies eat babies. That's pretty normal. Yeah. Don't some baby sharks eat? Like, do they really fight? There's one species of shark, yes, where they will basically eat each other in utero. Oh, yeah. The gladiator shark.

Yeah. They're called the gladiator shark. They should be. I think that one's a different animal. That has a shark applied to it. Like turtles or something. Yeah, like turtles. You know how mean turtles are.

When I look at hydrothermal vents, I don't feel like you could bury things there. There's always all kinds of crabs and lipstick all over the place. Where like where are you gonna put the eggs it's not just the it's not like right next to there's like a lot of area nearby that's warmer than the average piece of the ocean you're a shark you just eat whatever's in your way yeah well sari what do you think you haven't said anything because you know the right answer i think that's why no i don't i agree with you i don't think it's boring but I think that the eggs eating other or babies eating other

eggs seems like the most likely thing because that happens all the time. I didn't say boring. I said mundane. Oh, mundane. Yes. Synonym boring. The hydrothermal vent thing seems interesting. I don't know if sharks live that deep.

Yeah. I think they're sleeper sharks. They're like slow cold water sharks, I think. Yeah, you are correct. So, look at my big old brain. The third one, I know that sharks have really strong electric sensing goop in their heads. I forget what it's called. It's like a man's name and it starts with an A.

I thought it was called... We let the sharks name it. But yeah, there's like a man's name and it starts with an a capital a i thought it was called we let the sharks name it but yeah there's like goo in their foreheads that helps them sense electricity in the water yeah it's called the ampule of lorenzini okay lorenzini was the the man's name was thinking of, and the A was the... Whatever it is. It is. It's a goo. So maybe these two...

Go ahead and lock in number three. Whoa. Locking it in. Do the babies do it? Does freezing in an egg actually do anything? That's a good question. I already locked in, though, so... Oh, shoot.

You go, Stefan. Oh, no, I don't wanna. I'll go based on what you do. I'll choose the boring one, though, so. Oh, shoot. You go, Stefan. Oh, no, I don't want to. I'll go based on what you do. I'll choose the boring one, the second one. I'm going to do the hot eggs. Hot eggs. We have it spread out across three. All right, the true fact is that bamboo sharks are able to track the present.

Is that the one I said? Yeah. The goo babies. Sam has no idea. Was it because of the head goop? So, yes. By the time... So, these shark eggs are really interesting.

When they're first laid, they have, like, a stripe on them that makes them resemble poisonous prey animals. So, they, like, early on, when they're little eggs, they mimic a poisonous animal. And then as they get bigger bigger they start to look like the ground like pebbles so they're hard to spot and then once they get so big and like the the shark is so developed that they can't hide anymore the egg actually becomes permeable and the shark inside the egg can breathe the water so it's actually like breathing oxygen as a little baby shark still inside of its egg. But because of that, since water is permeating the membrane, it's much easier for predators to

smell them. So they noticed that they had their electrosensory organs developing, scientists noticed this, before they hatched. And they were like, well, why would that be? And so they ran like a predator-like electric field over these eggs and they freeze and they even like, well, why would that be? And so they ran like a predator-like electric field over these eggs and they freeze and they even stop breathing. So they just like completely, like they shut down their gills, they curl up in a ball and they're just like,

don't move, don't move, don't move. They're little scaredy sharks. They develop like multiple ways of like hiding. Man, eggs are delicious. They're just like little nutrition pouches. And they're so easy to eat. Yeah. So fact number two, the sand tiger sharks are actually the gladiator sharks.

Oh, okay. That consume each other in utero. And they are sometimes from multiple fathers. So like you'll have half brothers and sisters in there. It's like Maury. And so it's like, it's like Maury. Yeah. Like daytime talk shows,

except there's more murder. More bloodsport. Except that there's cannibalism. So like, which father has the strongest babies is the sort of, I guess, what you're trying to compete for.

So they can't team up and eat other eggs because they already killed each other. There is not a shark that lays eggs in hydrothermal vents, but there is an animal that does, and it's closely related to shark. It's the Pacific white skate. Scientists think, they're not sure, that it speeds up the development process of the eggs to be warmer. Now it is time for a

short break in which hopefully something will happen, but maybe nothing will. And then, the fact the Factos. Welcome back. Hank Buck total. Sari's still down at negative one. Oof. I've got one point. Dug myself out of that hole. And Sam and Stefan

are tied at zero. And now it's time for Sari and Sam to do the fact off. They have each brought science facts for us to enjoy, and we're going to give points to the one that we like the most. Sari, Sam, we're going to go based on who most recently got a loan. Oh, wow. A loan sharks. Did you see where I went there?

Yeah. I also got a car when I moved to Missoula. Is that with a loan? With a loan, sharks. Did you see where I went there? Yeah. I also got a car when I moved to Missoula. Is that with a loan? With a loan, yeah. I did not buy it with cash. I am still using the car I had in high school, which my mommy bought for me. So go first, I guess. Okay.

Great white sharks that normally live all along the North American coast spend their winter and spring in a Colorado-sized region in the mid-Pacific Ocean. Sharks of all ages and genders go, and it takes around 25 days for them to swim out there, and they stick around for around 100 days. And then they go back to the coast in the fall to munch on elephant seals and sea lions. So it's like a significant trip. This pattern was first discovered by getting data from 20 sharks in 2002. And it was really weird because shark behavior changed there, where the males did things called bounce dives as much as once every 10 minutes or 120 to 140 times a day. And females dove down in the day but stayed in shallow water at night. So it's just like weird shark behavior.

As far as we knew, this region was basically empty. Satellites didn't detect anything there, including food. So scientists were wondering, what was it? A secret oasis to take a break? A place to find a hot date? A place to have babies? Who knows? And because it was just kind of a generic gathering place, they started calling it the White Shark Cafe.

Okay, I guess. I would rather call it Shark Colorado. Yeah. Shark-or-ado. In 2018, researchers tracked 36 sharks in a boat called the Falkor. And then the tags on the sharks, when the Falkor went above them, they popped off. And then the researchers had to gather them off the surface of the ocean and find them. And they get information about temperature, pressure, light time, and how the sharks swam. And they did a close-up analysis of the DNA in

the water and found that it's actually a huge buffet for the sharks. Even though the satellites couldn't detect it, just under the surface, there's a really diverse ecosystem of fish and squids and crustaceans and jellies that make up a huge food chain, which is great for the sharks. Researchers still need to analyze what combination of like food or mating or other things attracts the sharks. And there might be more hidden cafes and other places in the deep ocean because the only way we found this one was because some researchers decided to track great white sharks at some point.

And they were like, why are all these sharks going into this weird patch of ocean for winter and spring? Why is Sharkorado such a diverse place with lots of food in it? It's in the middle of the ocean or something? Where is it? Yeah, it's like halfway between Hawaii and California. Maybe that's where they can get away from the boats. This is the only place I can be a fish anymore.

All the other fish go there too. And then they're like, oh God, who told the sharks? Who told the sharks about Sharkorado? We shouldn't have named it Sharkorano. All the scientists who are talking about it are kind of like, just like there are specialized communities in the middle of deserts,

there are also specialized communities in the middle of oceans, and especially these sort of vertical food chain layers that we see. So like there's smaller phytoplankton up at top. And then as it gets deeper and deeper, there are species more specialized to that level of light and that level of food and are generally bigger. And then there's also like complex ecosystems that have to do with migration with that. So like in the daytime, they hide deeper and then at night, then they go up

towards the surface because it's safer. And so there's all this kind of complicated life in patches in the ocean and we just don't know how to detect it using the satellite methods we have so when they're doing their diving were they going down to eat food and all the research that i read said it's a new mystery why they move differently through the water but they think they're diving down to get food or as part of like a mating ritual, maybe. Maybe they're working out. That makes so much sense. It's like more pressure. It's like resistance training.

You got to go straight down. We solved the mystery, Stefan. Yeah, call them up. Sam, can you top Sharkarado? I don't know. The Greenland shark is a very long living shark species that dwells in cold Arctic water. It's a kind of a sleeper shark. That's why i know this i'm a long living i mean like super long living like 300 to 500 years old so everything

about this shark is slow as hell which probably helps with it living so long in fact researchers believe it is literally the slowest fish in the entire world relative to its size and it swims at about one mile an hour but despite its slowness they are frequently found to have seals in their bellies and seals are crazy fast yeah they swim between 6 and 18 miles an hour so the general assumption was always that greenland sharks had the ability to kick in like an extra burst of speed when it was time to eat a seal and so to test this a bunch of researchers went out in 2012 and they tagged six Greenland sharks

and then they just sat and they watched their speed on these tags. And what they found was that they never went any faster. The most speed that they gained was like 0.25 more miles an hour. So they never engaged any kind of super speeds. So then the scientists just had to theorize as to how they catch them and this is what they came up with. Polar bears also eat seals. And polar bears are crazy faster than seals on land.

And they are pretty sneaky too. So to avoid getting chomped, seals sleep in the water. It's called bottling when they sleep in the water. They go straight up and down and they put their little noses above the ocean waves. So what they think is that Greenland sharks are also pretty sneaky just because they go so slow. So they can swim up to sleeping seals

and just chomp them up while they sleep. Where are they sleeping? In the ocean. Like just like on the surface of the water? Far enough away that polar bears can't swim out and get them. Greenland sharks are just like, instead of like, it's like,

Dun, dun, dun. Dun, dun, dun. Dun, dun, dun. Dun, dun, dun. But do they normally live deep? So is it weird for them to go shallow? It must not be that weird because this is like not been i couldn't find a lot of follow-up research on it but this seemed

like it was pretty accepted when the paper came out in 2012 nobody thought it seemed like a weird thing uh so and then chomp. So mostly I just thought it was really creepy that the slow guy would sneak up on you. That is creepy. And eat you while you're sleeping. I feel like the water is moving faster than one mile an hour.

Yeah. If there's any current, they're just like, well, bye. I feel like if you're like super slow and then you're like biting onto a fast moving seal, just like wiggle its way out. It opens its mouth and fully engulfs the seal. I don't think anybody's ever seen it happen. This is just their best guess of how it could possibly happen. I need to see it.

But they're big. I think they're a lot bigger than seals. So they can probably just go. Yeah, because if there's a struggle, I don't think they win. They're big. I think they're a lot bigger than seals. So they can probably just go. Yeah. Because if there's a struggle, I don't think they win. They're blind, too. They are? They have, I think, a parasite in almost all or all of their eyes.

What? Oh, no. That makes their eyelids all cloudy. What a dumb fish. Move faster. Geez. Are you sure they just don't like find dead ones? I don't know.

I just don't know. They must not think that they just find dead ones. Right. I mean, if scientists think they're eating live seals, they must be. Well, that's fascinating, Sam. I loved it. So we have to choose between Sam's sneaky, slow assassin shark and Sari's shark-er-ato.

The Colorado-sized patch of the ocean where great white sharks just chomp all summer long. Or winter long. We're changing the mechanics of this segment so that we say it on three so we don't influence each other's choices. Stefan, are you ready? Yeah. One, two,

three, Sari. Oh! We still split the difference. You each got's choices. Stefan, are you ready? Yeah. One, two, three. Sam. Oh, we still split the difference. You each got a point. Congratulations. Hooray. I'm at zero. And so now it's time to ask the science couch where we're going to ask listener questions to the beautiful yellow couches, finely honed scientific minds.

This week, the question is from at might be Joe. How and why did sharks evolve to have two penises? Well, this is definitely not for me. I didn't know that sharks had two penises. Me neither. Did they really know that they had penises? Right, well, a lot of fishes don't.

Cartilaginous fishes do have these appendages. The thing that I have learned about penises is that it's anything don't cartilaginous fishes do have these appendages the thing that i have learned about penises is that it's anything that deposits like the gametes it's like a like it's a sperm depositing device yeah but not everything well you know not everything has one but like oftentimes they are they are not similar to what i imagine a penis to be. So what I've learned after googling the word penis in so many different variations is that intermittent organs are like the blanket term for structures that place gametes into a mate for internal fertilization. Usually we're referring to sperm

in this case. So it's like delivers sperm. It's an intermittent organ. And the term penis applies to lots of intermittent organs, including all mammals, where this intermittent organ delivers sperm, but also carries urine out. But then in birds, where a lot of mating happens through cloacas,

the ones that don't use cloacas, like ducks, we call that a penis. This is where it starts getting fuzzy, where it seems like a bunch of biologists are just like, eh, it delivers sperm, it's a penis. And all the articles that you read will be like, the slug penis, the shark penis, the whatever. But a lot of them have more specific names than that,

usually when they're other modified body parts so like shark penises are not called penises often they're called claspers they're elongated modifications of the pelvic fins and they they are an intermittent organ so they help facilitate the transfer of sperm there are two of them And they get stuck into the female genital tract and help deliver sperm there. And there's a spur to hold it in and everything. But technically not a penis? I asked Twitter because I also didn't know. Stephanie Blyce, at Paleo Blyce,

she's a PhD paleontologist and evolutionary biologist, helped me out. She thinks, as far as she knows, it's a sort of generalized term for a single medial male intermittent organ that is not a modified something else. So single, as in there's one, as opposed to sharks, which have two claspers,

or like the hemipenes of, I don't know, a little squamate, like a lizard. What's a hemipene? You said too many things there that I don't understand. I'm so sorry. Just the hemipene of a squamate like a lizard you said too many things there that i don't i'm so sorry so lizards and snakes this is an excellent insult that i'm going to use the next time someone's being rude to like the gate agent at an airport i'll just be like you're being the hemipene of a squamate right now it's like a lizard or a snake penis it's a medial in the middle-ish of your body as opposed to like on the side i don't know forehead penis intermittent organs

as like an idea of you have an organ that delivers sperm has evolved many different times and many different lineages and it seems like only a select few regularly get called penises, like the ones in mammals, a few birds, barnacles. And then the rest is just an easier way to refer to this thing is like it does the sex. So it's a penis. I don't think anyone would yell at you if you called a shark penis a penis. But technically, they're not even a penis. Yeah. Or technically, by whose definition?

No one. No one has a defined penis and thus it is now my mission. Excuse me. Now, I love that we got this question and we're like, just so you know,

no one knows what a penis is. Okay, we have a loose definition of what is a penis so you can point to something and be like, this is within. You could say that is an intermittent organ but you cannot with to something and be like, this is within. You could say that is an intermittent organ,

but you cannot with certainty say penis is like... People disagree about what a penis is. There are things that everyone agrees is a penis, but there are things

that people don't agree on. The definition is you know it when you see it. Sounds very scientific, Sam. Anyway, how and why did sharks evolve to have two penises? They needed to deliver sperm.

And so they modified their fins. Yeah, and they had two fins. Yes, but they only used one at a time. Oh, interesting. So there's only one receptacle. Yes. And besides the earlier person I mentioned, thanks to at Diane A. Kelly for helping me understand that.

The interesting part of that question was not answering the question, which is, what is a dick? Yeah, no, you should have asked, what is the penis? Ask any biologist. I would love to know. Yeah. All right, if you want to ask the Science Couch

your questions, follow us on Twitter, at SciShowTangents, where we will tweet out the topics for upcoming episodes every week. Thank you to at LateOnTheTrain, at LaineyTheCyclist, and everybody else who sent us your questions this week. Thank you to at late on the train at Laney, the cyclist and everybody else who sent us your questions this week. Hank Buck final scores.

It's a two way tie between me and Sam, Sari and Stefan coming in second with zero points. Low scoring episode of all time for reasons that you can't even know because they were that bad. We just cut them out of the episode. If you like this show and you want to help us out, it's very easy to do that. First, leave a review wherever you listen. That's very helpful. It lets us know what you like about the show.

Also, we look at iTunes reviews for ideas for topics for future episodes. We've been getting a lot of really nice ones lately, too. Nice reviews. Thanks so much. Second, you can tweet us your favorite moment from the episode. And finally, if you want to show your love for SciShow Tangents, just tell people about us. Oh, God.

If you want to read more about any of today's topics, you can go to SciShowTangents.org to find links to all of our sources and maybe some good pictures of eye parasites and Greenland sharks. And shark penises. Shark and the hemipenes of the parasites and Greenland sharks. And shark penis. Shark and the hemi-peens of the squamates. Yeah. Thank you for

joining us. I've been Hank Green. I've been Sari Reilly. I've been Stefan Jin. And I've been Sam Schultz. SciShow Tangents is a co-production of Complexly and the wicked wonderful team at WNYC Studios. It's created by all of us and produced by Caitlin Hoffmeister and Sam Schultz who also edits a lot of these episodes along with Hiroko Matsushima. Our eerie

editorial assistant is Toboki Charpovardi. Our sinister sound design is by Joseph Tunamedish. Our scary social media organizer is Victoria Bongiorno. And we couldn't make any of this without our putrid patrons on Patreon. Thank you, and remember, the mind is not a coffin to be

filled, but a jack-o'-lantern to be lighted. But one more thing. This bro in South Carolina found a two-inch long coprolite, which is fossilized poop. It appears to be over 20 million years old, and it contains a shark tooth in it. When they examined it more closely, they figured out that it was ancient croc poop. This expert recognized the tooth as belonging to a cousin species of megalodon. On the flip side of the piece of poop,

there's like a bite mark that like you can see the serrations of the tooth. And so what they think happened is that like some sharks maybe are eating off of the seafloor and then like one was like, oh, here's a like blob. I'm going to try it out. But then was like, nope, that's poop.

Bye bye. But somehow broke off a tooth on this piece of poop and it got stuck in there for 20 million years. Man, that's such a terrible story to tell the dentist. Yeah. You're like, what's going on, Jeff?

Well, I bit of poop.