What is an octopus?

0:46 Welcome to Science Is Not Boring by kidopoly.com. I'm Mira. And I'm Finn. A massive shout out to Theo, who is eight and listens on the way to school in Canberra, Australia.

0:58 Hey Theo, you asked us all about octopuses. Their three hearts, blue blood, and incredible brains.

1:05 It's a great pick, Theo. And if you haven't already, tap follow wherever you're listening so you never miss an episode.

1:12 So, Mira, I know octopuses are smart, but how smart are we talking? Are they smarter than a dolphin? Can they do math?

1:21 Well, think about this. Imagine an animal with 500 million brain cells, which scientists call neurons. That is about the same amount of neurons as a dog has.

1:32 Wait, what? An octopus is as smart as a golden retriever.

1:37 Kind of, but it's way weirder than that. Their brains don't work like ours at all. In fact, two-thirds of their brain isn't even in their head. It is spread out completely across their eight arms.

1:50 Their arms have brains? Okay, I need to know absolutely everything about how that works.

1:56 Let's go back to the beginning. Octopuses are ancient. They've been roaming Earth's oceans since the Jurassic period, around 200 million years ago.

2:08 The Jurassic period? That means they were swimming around the ocean, right when the dinosaurs existed.

2:15 Exactly. And to survive that long, they had to evolve some totally wild biology. Let's start with their hearts. How many hearts do you have, Finn?

2:26 Just one, obviously. It beats right in the middle of my chest.

2:30 Well, an octopus has three. Yes, three separate beating hearts inside their squishy bodies.

2:38 Why would anyone need three hearts? Doesn't one do the job just fine?

2:43 It's all about their blood. Two of the hearts are called bronchial hearts. They pump blood directly to the gills to pick up oxygen from the ocean water.

2:53 Okay, so what does the third one do?

2:56 That one is called the systemic heart. It takes that freshly oxygenated blood and pumps it to the rest of the body.

3:03 Okay, three hearts working together as a team. But wait, Theo mentioned they have blue blood. Is that actually true or just a myth?

3:13 He is absolutely right. Human blood is red because it uses iron to carry oxygen. But octopus blood uses a totally different metal. It uses copper.

3:25 Copper? Like what you find in pennies and electrical wires.

3:29 Yes. The copper-rich protein is called hemocyanin, and it literally turns their blood a deep rich blue. Down in the deep ocean, the water can be near freezing, and oxygen is super scarce. The copper is actually way better at carrying oxygen in those freezing conditions.

3:48 That is incredible. They are like deep-sea aliens.

3:51 Scientists actually joke about them being aliens all the time. But the craziest part is their nervous system. You remember those 500 million neurons?

4:03 Yeah, the brain cells. You said most of them are in their arms, which sounds totally impossible.

4:09 It sounds impossible, but it is true. Imagine if your hand could taste, touch, and think all on its own, without your brain telling it what to do. That is what an octopus arm does.

4:23 No way! They can actually taste things with their arms.

4:27 Yes. Each of their eight arms has over 200 little suction cups, and each single sucker is packed with up to 10,000 neurons.

4:37 10,000 in just one sucker. So when they touch a rock or a crab, they are tasting it at the same time.

4:44 Exactly. And because the arms have their own mini brains, they can react without waiting for the central brain to give an order.

4:51 So the central brain just says, go find food. And the arms figure out how to do it. Like little independent robots.

5:00 You got it! Scientists have even seen that if an arm gets completely separated, it will still pull away from danger or try to grab food all on its own. The arms talk to each other without the central brain even knowing.

5:15 Okay, that is slightly freaky, but also incredibly cool. They are the ultimate multitaskers.

5:21 Ready to hear what they can actually do with all those smarts out in the wild.

5:26 Yes, tell me, do they build underwater cities?

5:29 Not quite, but there is a marine biologist named Dr. Julian Finn.

5:34 Hey Julian Finn, he has the best name ever. What did he do?

5:40 I thought you would like that. Dr. Finn and his team spent over 500 hours diving off the coast of Indonesia to watch a specific species called the veined octopus.

5:52 What was so special about this specific octopus that they watched it for 500 hours?

5:57 He noticed them digging through the sand to find discarded coconut shells that had sunk to the ocean floor. But they didn't just hide inside them. They emptied the shells out, stacked them together like bowls, and literally carried them away.

6:13 Wait, they carry coconuts? How do you carry a heavy coconut if you don't have hands or bones?

6:20 They tuck the stacked shells underneath their squishy body, stiffen their eight arms so they act like rigid legs, and basically stilt walk across the ocean floor. They can carry them up to 65 feet.

6:33 That is a huge distance for a little octopus. But why do they go through all that trouble to carry them?

6:39 They use them as portable armour. If a predator comes near, the octopus stops, flips the two halves of the coconut over itself, clamps the shells together from the inside, and completely hides.

6:52 So they literally build a shield out of coconuts. That is genius!

6:57 Yes, and this discovery totally shook the world of science. It was the very first time an invertebrate animal was ever proven to use tools in the wild.

7:08 Because usually only animals like monkeys, chimpanzees, or birds do that, right?

7:13 Exactly. For a long time, humans thought mammals were the only smart ones. But octopuses proved that you don't need a backbone to be an absolute genius.

7:23 What else can they do? Any other crazy tricks hidden up their sleeves? Or tentacles?

7:30 Oh, so many! They are absolute masters of disguise. Their skin is packed with thousands of special cells called chromatophores. Chromato what? What do those do? Chromatophores. They are tiny sacks of colour that expand and contract like tiny muscles. This lets the octopus change its skin colour in milliseconds, while structures called papilla change its physical texture to match a rock perfectly.

7:58 Like a real-life invisibility cloak. Wait, do they have any bones under all that changing skin?

8:05 Nope, not a single bone. The only hard part of their entire body is a sharp beak, shaped almost exactly like a parrot's beak, which they use to crack open crabs. Because they are completely squishy, a giant Pacific octopus can squeeze its massive body through a tiny hole.

8:25 Squeezing through a tiny hole? That is terrifying and awesome. What about in aquariums? Do they play tricks on scientists? All the time.

8:35 A giant Pacific octopus can weigh up to 110 pounds and have an armspan of 16 feet. But they are notorious escape artists. They have been known to solve complex mazes easily.

8:49 No way! A giant octopus doing mazes!

8:52 Yes, and my absolute favourite fact: they are so smart and so incredibly strong, they can unscrew a glass jar from the outside to get food and from the inside to escape.

9:05 They unscrew jars from the inside? Okay, they are officially the coolest animals ever to live on Earth.

9:11 Alright, Finn, it is quiz time! Let's see how much you remember from today's crazy octopus adventure.

9:18 Okay, my brain is ready. Hopefully it is as smart as a golden retriever. Bring it on!

9:25 First question. How many beating hearts does an octopus have inside its body? Next one. What specific metal is in their blood that turns it a deep rich blue? Question three. How many millions of neurons do they have, which makes them about as smart as a dog? Here is number four. What object does the veined octopus carry across the ocean floor to use as a portable shield?

10:04 Last question. During what ancient period did octopuses start roaming the Earth's oceans. Great job! Let's go through the answers and see how you did. The first answer is three hearts, two bronchial hearts for the gills, and one systemic heart for the rest of the body. For question two, the metal is copper.

10:30 It helps them survive and carry oxygen in freezing deep water. The answer to number three is five hundred million neurons, and two-thirds of them are all spread out in their arms. For question four, coconut shells. They stack them and stilt walk with them as portable armour. And the final answer is the Jurassic period.

10:55 They are truly ancient survivors that lived alongside dinosaurs.

10:59 Honestly, the idea of a squishy animal carrying a coconut shield across the sand and escaping a jar from the inside is just unbelievable. Science is wild.

11:11 I know, they really are like real-life superheroes. If you love learning about coconut carrying octopuses, please leave us a five-star review. Just scroll down and tap the stars. And be sure to follow this show wherever you are listening.

11:25 Oh, and we have sister shows too. They are called History and Philosophies Not Boring and Maths Is Not Boring. Go give those a listen and a follow as well.

11:35 And if you want to shout out on the show or just want to say hi, email us at hello at kidopoly.com.

11:42 Keep asking great questions, Theo, and keep exploring everyone. There is always something new to learn.

11:49 See you next time on Science is Not Boring. Bye.