# What are sharks?

An episode of [Science for Kids / Science's Not Boring: The Kids Science Podcast](https://invisiblenetwork.ai/podcast/1896928296), 7 Aug 2026, 13 min.

Audio: https://www.buzzsprout.com/2624612/episodes/19579320-what-are-sharks.mp3

Did you know that sharks are actually older than trees, older than dinosaurs, and even older than the rings of Saturn?! Dive into the deep blue sea with Mira and Finn to uncover the amazing, real-life secrets of the ocean's most misunderstood creatures! Forget what you've seen in scary movies—sharks are ancient survivors with actual superpowers. Discover how they use special jelly-filled pores to literally feel the heartbeat of a fish hidden under the sand! Want to hear something totally gross? Find out the crazy (and disgusting!) way a shark cleans out its tummy by throwing its entire stomach out of its mouth! Eww! We'll also meet the biggest fish in the entire world, a massive 60-foot giant that weighs as much as ten elephants but eats some of the tiniest food in the ocean. Plus, learn about a freezing cold, deep-sea shark that can live for over 400 years! Join us for this fin-tastic underwater adventure to find out why sharks are actually incredible ocean guardians that need our protection. Don't worry, the only thing you'll catch is some seriously awesome knowledge!

## Transcript

[0:00] SPEAKER_00: Welcome to Science Is Not Boring by Kidopoly.com.
[0:04] SPEAKER_00: I'm Mira! And I'm Finn.
[0:07] SPEAKER_00: Fin, I want you to picture the oldest thing you can think of.
[0:12] SPEAKER_01: Um, a really old tree?
[0:15] SPEAKER_01: Like one of those giant redwoods that is super wide.
[0:18] SPEAKER_00: That's exactly what most people think.
[0:21] SPEAKER_00: But what if I told you that the creatures we're talking about today are actually older than trees?
[0:28] SPEAKER_00: No way! Trees have been around forever! The very first trees, like Archaeopteris, sprouted about 385 million years ago.
[0:38] SPEAKER_00: But sharks?
[0:39] SPEAKER_00: They've been swimming in our oceans for 450 million years.
[0:44] SPEAKER_01: 450 million years?
[0:47] SPEAKER_01: That means they were here before the dinosaurs.
[0:50] SPEAKER_00: Way before.
[0:51] SPEAKER_00: They are older than dinosaurs.
[0:53] SPEAKER_00: They're older than the Atlantic Ocean.
[0:56] SPEAKER_00: They are even older than the rings of Saturn.
[0:59] SPEAKER_01: Okay, my brain just short-circuited.
[1:01] SPEAKER_01: Sharks are older than Saturn's rings.
[1:04] SPEAKER_00: It sounds made up, but it's totally true.
[1:07] SPEAKER_00: Today, we're diving deep into the true story of sharks.
[1:11] SPEAKER_00: We'll find out how they sense a hidden heartbeat, why the biggest shark of all eats the tiniest food, and why they aren't the monsters the movies make them out to be.
[1:21] SPEAKER_00: I'm ready.
[1:22] SPEAKER_01: Just don't let them bite me.
[1:23] SPEAKER_00: Let's start with the basics.
[1:25] SPEAKER_00: What actually makes a shark a shark?
[1:28] SPEAKER_00: Oh, I know this.
[1:29] SPEAKER_00: It's the teeth.
[1:30] SPEAKER_00: Rows and rows of razor-sharp teeth.
[1:33] SPEAKER_00: Well, they do have amazing teeth, but the real secret is their skeleton.
[1:38] SPEAKER_00: Sharks don't have a single bone in their bodies.
[1:41] SPEAKER_01: Wait, what?
[1:42] SPEAKER_01: No bones at all?
[1:44] SPEAKER_01: How do they not just flop around like jellyfish?
[1:47] SPEAKER_00: Their skeletons are made entirely of cartilage.
[1:50] SPEAKER_00: Go ahead and wiggle the tip of your nose, or fold your ear.
[1:53] SPEAKER_00: Haha, okay, I'm wiggling my nose.
[1:56] SPEAKER_00: It's bendy! That's cartilage.
[1:59] SPEAKER_00: It's lighter and more flexible than bone, which helps sharks swim fast and turn on a dime.
[2:04] SPEAKER_00: And they've had this brilliant design for a very long time.
[2:08] SPEAKER_01: Right.
[2:08] SPEAKER_01: Back to that 450 million years thing.
[2:11] SPEAKER_00: Where exactly were they hanging out?
[2:14] SPEAKER_00: Imagine Earth in a time called the late Ordovician period.
[2:18] SPEAKER_00: There were no forests, no mammals, not even insects on land, just mosses and bare rock.
[2:24] SPEAKER_00: Ooh, that sounds super boring.
[2:27] SPEAKER_00: On land, maybe.
[2:29] SPEAKER_00: But under the water it was a massive single ocean called Panthalassa.
[2:33] SPEAKER_00: And that's where the first shark ancestors appeared.
[2:36] SPEAKER_01: How do scientists even know that if they don't have bones to leave behind as fossils?
[2:40] SPEAKER_00: Because cartilage doesn't fossilize well, paleontologists rarely find full skeletons of the earliest sharks.
[2:47] SPEAKER_00: Instead, they find tiny tooth-like scales called dermal denticles hidden in ancient rocks.
[2:54] SPEAKER_00: Tooth-like scales?
[2:55] SPEAKER_00: You mean their skin is made of teeth?
[2:58] SPEAKER_00: Exactly! Shark skin is covered in thousands of tiny V-shaped scales that make them incredibly hydrodynamic, meaning they glide through the water with almost zero drag.
[3:09] SPEAKER_01: So they're basically swimming torpedoes wrapped in sandpaper?
[3:13] SPEAKER_00: Yes, and over the last 450 million years, they've survived five mass extinctions.
[3:19] SPEAKER_00: Asteroids, ice ages, massive volcanic eruptions.
[3:23] SPEAKER_00: Sharks outlived them all.
[3:25] SPEAKER_01: Okay, if they survived five apocalypses, they must have some kind of superpowers, right?
[3:31] SPEAKER_00: They absolutely do.
[3:33] SPEAKER_00: Let's travel to the year 1678.
[3:36] SPEAKER_00: An Italian scientist named Stefano Lorenzini was examining sharks and noticed a weird pattern of tiny pores all over their snouts.
[3:46] SPEAKER_01: Like a shark moustache.
[3:48] SPEAKER_00: Kind of.
[3:48] SPEAKER_00: He described them as looking like a bad five o'clock shadow, but he couldn't figure out what these pores actually did.
[3:55] SPEAKER_00: So what were they?
[3:56] SPEAKER_00: It took nearly 300 years for scientists to solve the mystery.
[4:00] SPEAKER_00: In the 1960s, researchers discovered these pores are connected to jelly-filled tubes called the ampoli of Lorenzini.
[4:09] SPEAKER_01: Ampalae of Lorenzini?
[4:11] SPEAKER_01: That sounds like a fancy pasta dish.
[4:14] SPEAKER_00: It does, but they are actually electro receptors.
[4:17] SPEAKER_00: Every time a fish breeds or a crab twitches a muscle, it creates a microscopic electrical field in the water.
[4:24] SPEAKER_01: Wait, you're saying sharks can literally feel electricity?
[4:29] SPEAKER_00: Yes.
[4:30] SPEAKER_00: Even if a fish is completely buried in the sand, a shark can sense its heartbeat from inches away.
[4:36] SPEAKER_00: The ampoli of Lorenzini detect the tiny voltage of the beating heart.
[4:41] SPEAKER_01: That is the coolest superpower ever.
[4:43] SPEAKER_01: But wait, do they have any powers that are just completely gross?
[4:47] SPEAKER_01: You know I love the gross stuff.
[4:50] SPEAKER_00: Oh, I have the perfect one for you.
[4:53] SPEAKER_00: It's called gastric aversion.
[4:55] SPEAKER_01: That sounds too scientific.
[4:57] SPEAKER_00: What does it mean?
[4:58] SPEAKER_00: Imagine a shark eats something it shouldn't.
[5:01] SPEAKER_00: Maybe a turtle shell, or a bird feather, or just some bad food.
[5:06] SPEAKER_01: Okay.
[5:07] SPEAKER_01: What do they do?
[5:08] SPEAKER_01: Drink some shark medicine?
[5:09] SPEAKER_00: Nope.
[5:10] SPEAKER_00: In less than a second, the shark will literally throw its entire stomach out of its mouth, flip it inside out into the water to rinse it off, and then swallow it back down.
[5:21] SPEAKER_00: Ew, ew! They puke their actual stomach.
[5:26] SPEAKER_00: Yes, it's like turning your pockets inside out to dump out the lint.
[5:30] SPEAKER_00: Marine biologists often see this when a shark is stressed.
[5:34] SPEAKER_00: It's a super fast way to clean their insides.
[5:38] SPEAKER_01: Okay, I asked for gross and you delivered.
[5:40] SPEAKER_01: I am officially freaked out.
[5:42] SPEAKER_00: Well, let's talk about a shark that's more gentle giant than terrifying predator.
[5:48] SPEAKER_00: It's the biggest fish in the entire ocean.
[5:51] SPEAKER_00: Oh, I bet it's huge! How big are we talking?
[5:55] SPEAKER_00: Like a school bus?
[5:56] SPEAKER_00: Bigger! The whale shark can grow up to 60 feet long.
[6:00] SPEAKER_00: That's as long as a bowling lane.
[6:03] SPEAKER_00: 60 feet?
[6:04] SPEAKER_00: How much does a bowling lane-sized shark weigh?
[6:07] SPEAKER_00: They can weigh up to 40 tonnes.
[6:10] SPEAKER_00: That is 80,000 pounds.
[6:12] SPEAKER_00: Imagine stacking 10 adult elephants on a giant scale.
[6:16] SPEAKER_00: That's one whale shark.
[6:18] SPEAKER_00: 80,000 pounds?
[6:20] SPEAKER_00: If they are that big, what do they eat?
[6:23] SPEAKER_00: Whole submarines?
[6:25] SPEAKER_00: That's the craziest part! The biggest shark in the ocean eats some of the smallest food in the sea.
[6:32] SPEAKER_00: They survive mainly on plankton, krill, and tiny fish eggs.
[6:36] SPEAKER_00: Wait, really?
[6:38] SPEAKER_00: Tiny little krill?
[6:39] SPEAKER_00: How do they even catch them?
[6:41] SPEAKER_00: A whale shark has a mouth that can stretch five feet wide.
[6:45] SPEAKER_00: Picture a mouth the size of your bed.
[6:48] SPEAKER_00: Okay, that's slightly terrifying.
[6:50] SPEAKER_00: But it's totally harmless to us.
[6:53] SPEAKER_00: They are filter feeders.
[6:54] SPEAKER_00: They swim with their massive mouths wide open and act like giant vacuum cleaners.
[7:00] SPEAKER_00: They can gulp down and filter over 6,000 litres of water every single hour.
[7:06] SPEAKER_00: 6,000 litres?
[7:07] SPEAKER_00: How much is that?
[7:09] SPEAKER_00: That's enough to fill 20 huge bathtubs every hour, just pushing water out through their gills and trapping the tiny food inside.
[7:18] SPEAKER_01: So if I was swimming and a whale shark opened its five-foot mouth, would I get sucked in?
[7:24] SPEAKER_01: Nope.
[7:25] SPEAKER_00: Even though their mouths are huge, their throat is only about the size of a baseball.
[7:29] unknown: Ha ha!
[7:30] SPEAKER_01: A baseball! A 40-ton shark has a throat the size of a baseball.
[7:35] SPEAKER_01: Exactly!
[7:36] SPEAKER_00: They couldn't swallow you even if they tried.
[7:39] SPEAKER_00: In fact, divers swim right next to them all the time.
[7:42] SPEAKER_00: They are completely peaceful.
[7:44] SPEAKER_00: They cruise at a super slow speed of about three miles per hour.
[7:48] SPEAKER_01: Just slowly vacuuming up the ocean.
[7:51] SPEAKER_01: That's actually kind of adorable.
[7:53] SPEAKER_01: Right?
[7:54] SPEAKER_00: And that brings us to the biggest misunderstanding about sharks.
[7:58] SPEAKER_01: Let me guess.
[7:59] SPEAKER_01: The scary movies?
[8:01] SPEAKER_00: Yes.
[8:02] SPEAKER_00: Movies make sharks look like terrifying monsters that want to eat humans.
[8:07] SPEAKER_00: But let's look at the real numbers.
[8:10] SPEAKER_00: Across the entire world, sharks cause fewer than 10 human fatalities a year.
[8:16] SPEAKER_00: Less than 10 in the whole world?
[8:18] SPEAKER_00: Yes.
[8:19] SPEAKER_00: But the impact humans have on sharks is actually devastating.
[8:24] SPEAKER_00: Humans kill an estimated 100 million sharks every single year.
[8:30] SPEAKER_00: 100 million?
[8:32] SPEAKER_00: Why so many?
[8:33] SPEAKER_00: Mostly from being caught accidentally in giant fishing nets, a process called bycatch.
[8:40] SPEAKER_00: And for shark fin soup.
[8:42] SPEAKER_00: But sharks are apex predators.
[8:45] SPEAKER_00: They keep the ocean food web perfectly balanced.
[8:48] SPEAKER_00: Without them, the whole ocean ecosystem could collapse.
[8:52] SPEAKER_01: We have to protect them.
[8:54] SPEAKER_01: They survived asteroids.
[8:56] SPEAKER_01: They shouldn't get wiped out by fishing nets.
[8:58] SPEAKER_00: Exactly! And before we move on, I have to give you one more mind-blowing fact.
[9:04] SPEAKER_00: It's about a deep sea creature called the Greenland Shark.
[9:08] SPEAKER_00: The Greenland Shark?
[9:10] SPEAKER_00: Do they live in the freezing cold?
[9:12] SPEAKER_00: Yes, deep in the Arctic waters.
[9:15] SPEAKER_00: And because the water is so cold, their metabolism is incredibly slow.
[9:20] SPEAKER_00: Are you ready for how long they live?
[9:23] SPEAKER_00: I don't know.
[9:24] SPEAKER_00: A hundred years?
[9:25] SPEAKER_00: Try over 400 years.
[9:28] SPEAKER_00: 400 years?
[9:30] SPEAKER_00: Yes.
[9:31] SPEAKER_00: Scientists studied a Greenland shark.
[9:34] SPEAKER_00: They estimate could have been born around the year 1500.
[9:38] SPEAKER_00: It was swimming in the ocean before William Shakespeare was even born.
[9:42] SPEAKER_00: Alright, Finn, it's time for the quiz! Are you ready to test your shark knowledge?
[9:47] SPEAKER_01: Oh boy, I hope my brain doesn't avert like a shark stomach.
[9:51] SPEAKER_01: I'm ready!
[9:52] SPEAKER_00: First question.
[9:54] SPEAKER_00: How many millions of years ago did sharks first appear in the ocean?
[10:01] SPEAKER_00: Next one.
[10:02] SPEAKER_00: What is the name of the special pores that let sharks sense electricity?
[10:10] SPEAKER_00: Question three.
[10:12] SPEAKER_00: What crazy trick do sharks do with their stomach when they need to clean it?
[10:20] SPEAKER_00: Here's number four.
[10:21] SPEAKER_00: What is the largest species of shark in the ocean?
[10:28] SPEAKER_00: Last question.
[10:29] SPEAKER_00: How many hundreds of years can a Greenland shark live?
[10:37] SPEAKER_00: Great job! Let's see how you did.
[10:39] SPEAKER_00: The first answer is, sharks appeared about 450 million years ago, way before trees.
[10:47] SPEAKER_00: For question two, those electricity sensing pores are called the ampullae of Lorenzini.
[10:53] SPEAKER_00: Number three, the answer is gastric aversion.
[10:57] SPEAKER_00: They throw their stomach out of their mouth to rinse it.
[11:01] SPEAKER_00: Question 4.
[11:02] SPEAKER_00: The largest is the whale shark, which can grow up to 60 feet long.
[11:07] SPEAKER_00: And the final answer is a Greenland shark can live over 400 years.
[11:13] SPEAKER_01: Man, sharks are so much cooler than the scary movies show.
[11:17] SPEAKER_01: 450 million years of survival is serious business.
[11:21] SPEAKER_01: I'm never going to look at them the same way again.
[11:24] SPEAKER_00: It really is.
[11:25] SPEAKER_00: They went from dodging asteroids to sniffing out heartbeats in the sand.
[11:29] SPEAKER_00: They are ancient marvels of nature.
[11:32] SPEAKER_00: I hope you guys loved learning about the real story of sharks as much as we did.
[11:37] SPEAKER_01: Yeah, and hey, if you loved this episode, please leave us a five-star review.
[11:42] SPEAKER_00: Exactly! Just scroll down on your podcast app and tap those five stars.
[11:47] SPEAKER_00: Think of it as giving a five-star rating to the whale shark for being such a gentle giant.
[11:53] SPEAKER_00: Or to the Ampule of Lorenzini for being the coolest superpower ever.
[11:58] SPEAKER_01: Haha, a 40-ton giant with a baseball-sized throat.
[12:02] SPEAKER_01: It really is amazing.
[12:04] SPEAKER_01: Oh, and don't forget to check out our site, kidopoly.com.
[12:08] SPEAKER_01: We've got tons of awesome learning games and activities over there.
[12:11] SPEAKER_00: Yes, head over to our site kidopoly.com for so much more fun stuff to explore.
[12:17] SPEAKER_00: And if you want your name on the show, or just want to tell us your favourite weird shark fact, send us an email at hello at kidopoly.com.
[12:26] SPEAKER_01: We love hearing from you guys.
[12:27] SPEAKER_01: Maybe you can find a grosser fact than stomach aversion.
[12:32] SPEAKER_00: I doubt it.
[12:33] SPEAKER_00: Thanks for exploring the ocean with us today.
[12:36] SPEAKER_00: See you next time on Science is Not Boring.
[12:39] SPEAKER_00: Bye everyone.
[12:40] SPEAKER_00: Watch out for those tiny krill.

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