The Octopus and the Jam Jar - EWTS #023

Joe: Hello and welcome to Enough with the Science. I'm Joe.

Senan: And I am Senan. This is the show where we tell you things we know nothing about.

Joe: Well, I hope that's not true. Just to start the show because this is a very interesting topic now this week; I have to say you destroyed a movie for me based on this topic. I'll come back to that. Off you go with this week's topic, but don't let me forget to chastise you for destroying a movie for me.

Senan: Okay. I'll be sure to remind you of that. Anyway Joe, aliens. NASA have spent billions searching for life on other planets. All along they've been amongst us, watching us quietly with their nine brains and their eight legs and we just aren't even aware they're amongst us.

Joe: You see, you just got it wrong, they should have eight brains and eight legs.

Senan: That's the problem, there's an excessive brain.

Joe: That's why there's an excessive brain.

Senan: So we're talking of course about octopi.

Joe: I don't think most people know that. I don't think most people know that an octopus has nine brains.

Senan: Probably not.

Joe: When you go nine brains, of course it's an octopus. People are going, there's no animal with nine brains, that's the stupidest thing I've ever heard in my life.

Senan: Nine brains, three hearts, eight legs, hundreds of tongues.

Joe: Wow. Okay.

Senan: So the reference to an alien there; that is actually a comment you'll often hear some marine biologists say that the octopus are like the aliens living amongst us. The reason they say that is that it's a long, long time since we and octopi had a common ancestor on the evolutionary tree.

Senan: We're talking about 600 or 700 million years ago since our branch of the tree split off from their branch. That common ancestor was a pretty stupid worm that certainly didn't have anything resembling a brain. In fact, if I could borrow a quote from George Clooney, he was probably dumb as a bag of hammers.

Joe: Don't you talk about your grandparents like that! [laughter]

Senan: It certainly didn't have anything resembling a brain.

Senan: Which is a movie I love that you're not allowed ruin for me.

Joe: I'm writing it down. What's it called? I'm going to destroy that movie.

Senan: O Brother, Where Art Thou?

Senan: Oh yeah. Just to put that in context; we split off from their branch of the tree 600 or 700 million years ago at a time when the creature was pretty dumb. We're much more closely related to birds than we are to an octopus. We split off from the birds' branch of the tree only 300 million years ago. That kind of puts it in context.

Senan: What that means is that we know now that an octopus is a pretty intelligent creature based on the behaviour we observe. It must have evolved that intelligence completely separately from the way our branch of the tree evolved its intelligence. So in many ways that intelligence must be alien to our way of thinking.

Joe: Sometimes I think intelligence is alien to our way of thinking. [laughter]

Senan: It's a variable quality, isn't it?

Joe: It's very hard to define.

Senan: It's not just their intelligence. They have all these other weird aspects of their biology which are so unlike anything else that we have.

Joe: They're almost like an animal that just at various stages of its evolution went, let's give this a go. I have six legs, get another one, just for the craic. [laughter]

Senan: Let's talk about their basic body structure first. We and birds have a skeleton. We have bones that essentially give the structure and support for our body. Octopus don't have that. They're reliant completely on their muscles. They're basically a ball of muscle to maintain the shape and structure of their body.

Joe: Kind of like Conor McGregor.[laughter]

Senan: I am not going to go down that road. [laughter] The only rigid structure they have is a beak which they use for eating and catching prey.

Joe: What is it called, a beak? Is it like a bird's beak?

Senan: It's apparently shaped quite like a parrot's beak. But relative to the size of the octopus's body, it's very small. It's almost never seen because it's in the centre of where all the eight legs come together.

Senan: Basically, they can squeeze through any gap that's wider than that beak. Which means they can get through really, really tiny little holes that you wouldn't expect your finger to go through. It's a great ability they have to squeeze through narrow gaps in reefs and things when they're trying to hide or trying to find prey.

Senan: The camouflage thing is really amazing. This is one of the things that first turned me on to octopuses as an example of just weird biology. They can change colour instantly. They're probably the only creature we know of that can change to an unlimited range of colours in a split second.

Joe: I would imagine in some laboratory somewhere they had the full range of colours laid out on a table and they just dropped them to see like, okay, can you do this colour? Can you do this colour?

Senan: Obviously the octopus evolved in a marine environment. So probably it can only do the colours you would find in the sea.

Joe: Can it do burnt sienna? [laughter]

Senan: If you could burn sienna underwater, perhaps it could.

Joe: Marine colours. Gotcha.

Senan: The way it does it is really interesting. Its skin is covered in thousands of these little colour sacs called chromatophores that can be opened and closed. Around each one is a tiny little muscle that opens or closes that colour. Certain sacs are opened fully, certain are open half, certain are open a quarter, some are not open at all; it's by mixing the different colours that it's able to produce this huge range of different colours.

Senan: Why does it do it? Because it wants to camouflage depending on what surface. If it's on a dark rock it will go dark, then if it swims off the rock onto a sandy seabed it will go a light sandy colour instantly.

Joe: I'm sure Fleetwood and Dulux must be looking at this going wow. Like the wall... you'd just press a button, different colour. Press a button, different colour.

Senan: Perhaps not, because then they wouldn't be able to sell us a new can of paint every now and again. They could charge us a million euro for the first wall though.

Senan: It's not only colours. They can actually have bands of different colours at the same time, or spots. You can get these really rapid patterns moving across their skin, which is a way they've been observed communicating.

Joe: Dancing. Disco octopus! [laughter]

Senan: In their mating rituals, that's part of the way that they communicate with each other or display to each other for mating rituals, is by changing these patterns rapidly.

Joe: It's a myth because they were so good at camouflage I'm amazed they haven't been wiped out. They couldn't find each other to mate. [laughter]

Senan: It's even been documented that say there's a rival male on one side and a female that the male is interested in on the other side. They have even observed on the side facing towards the rival male, a neutral sandy colour, and on the side facing towards the female that the octopus is interested in, this mad display of patterns and colours going on.

Senan: Literally the creature's body, two halves of it doing completely different things. It's even aware that the guy on one side might see stuff that's going on on the other side and vice versa. It's really weird.

Senan: Imagine the nervous system that must be required to control that. You've got these thousands of little sacs all of which can be opened or closed individually. You've got this really extensive nervous system. You've got one nerve for each sac to open or close the muscle, instantaneously. The internal wiring there must be phenomenal.

Senan: It's not even restricted to colour, they're also able to dramatically alter the texture of their skin. Again this is all for camouflage, because sometimes they might be on a real smooth surface like say the leaf of a piece of seaweed, and they would have perfectly smooth green skin. Next thing they might move onto a grey rock that's got loads of little nobbles, maybe it's a volcanic rock with loads of rough little bumps on it. Suddenly the bumps appear on their skin. Their skin rises up into bumps that could be an inch high. It's amazing the control they have over all of their skin.

Joe: To do it instantaneously though. Not only can they make the colours, but they have to mimic the colours that they're on. So they have to get that information in and then change colour. There's no time... it's not like okay let's process this, what colour is that, it's kind of beige, okay throw this together.

Senan: They are very vulnerable to predators because they don't have any hard shell on the outside. So anything that's larger than them can kill them. So they either have to be able to hide or camouflage themselves so they're not noticed by predators. Their evolution came up with that solution to the problem of them getting eaten all the time. Pretty cool stuff.

Joe: I'm sure the Department of Defence is very interested in all of this technology.

Senan: We just need to skin all the octopi and then stretch that skin on...

Joe: Stretch that skin on oil supertankers. Straight through the Strait of Hormuz!

Senan: Right, so that's their external body. What about their internal body? Well, it's really cool, they have blue blood.

Joe: Oh yes. The upper classes. The upper class octopi. [laughter]

Senan: They're the princes of the ocean, aren't they? Why is our blood red? We have a molecule called haemoglobin that's based on iron that is responsible for carrying oxygen around our blood. The way iron when it rusts goes an orange colour, that's because the oxygen has reacted to produce iron oxide.

Senan: Well, the haemoglobin reacts with oxygen to carry an oxygen molecule around our body. When that reaction happens the haemoglobin goes red, hence we have red blood. In actual fact, veins are bluish for us or not quite as red as arteries are because the veins are carrying blood that has less oxygen in it than the arteries.

Senan: For the octopus it's a different story. They don't have haemoglobin. They have a copper-based molecule instead doing the same job, called haemocyanin. When that reacts with oxygen it goes blue, that's how come their blood is blue.

Senan: The reason they have that is that they evolved in a completely different way to us so it's not surprising they come up with a different solution to the problem of carrying oxygen. They evolved in a very cold environment. The amount of oxygen that's dissolved in seawater is not a whole lot. Not much oxygen and a very cold environment. Haemoglobin doesn't work terribly well in that situation, whereas this copper-based molecule they have in their blood just works better in that environment. However, it does result in blood that's more viscous, thicker, harder to pump. Their solution to that problem is they have three hearts.

Joe: Wow. They just make things difficult for themselves. [laughter] Are they just unique in these sort of solutions? Do other animals under the water have blue blood?

Senan: Squid are certainly related to them. I'm not sure if squid have the same kind of blood, but squid are fairly closely related, so I wouldn't be surprised if squid also have that. Whether anybody outside of that family has the blue blood or not, I'm not sure to be honest.

Senan: Any creature under the water that's extracting its oxygen from the water itself, they have gills. Two of those hearts are smaller and their only job is to pump that viscous thick blood through the gills. Then they've got this other larger heart that's like the main heart.

Joe: Just to fall in love. It's just to fall in love. [laughter]

Senan: So the larger central heart is the one that pumps the blood around the body. But yeah, three hearts, it's interesting.

Senan: The weirdness only goes on from there. They're also a great example of something in biology that's called convergent evolution. It's this idea that if you take two distant branches of the evolutionary tree, two types of creatures that are unrelated to each other, and they both evolved the same solution to a particular problem. It's an interesting idea that somehow nature found the right way twice by accident.

Senan: In this case we're talking about their eyes. The common ancestor we had with them 600 or 700 million years ago would not have had eyes of any kind. Octopus and us mammals and birds, the eyes all work broadly speaking the same. They've evolved independently an eye that works the same as our eye, which is pretty cool.

Senan: And is better than our eye in one way. We have a blind spot. We've got all these light-sensitive cells in our retina. Nerves have to connect to them to carry the signals of what we're seeing up to our brain. The wiring for those nerves, it comes around the front of our retina. But to get to the brain which is behind our retina, there has to be a hole for the wires to go through. That's what the blind spot is.

Senan: Now we're not consciously aware of the fact that we have a blind spot because our brains have basically learned to ignore it, but there are tests you can do that will demonstrate that you have a blind spot in your vision. Our friends the octopus did it the right way around. They put the wires behind the retina. So they don't need a hole in their retina, they have no blind spot. Because their wiring goes from behind the retina back to the brain.

Joe: So you're saying technically their eyes are better than ours?

Senan: Technically in that regard at least, their eyes are better than ours.

Joe: And also they keep their eyes open underwater.

Senan: Well we can too but it's not very comfortable for us. [laughter] And all you see is this blurry mash up of colours, you can't really see anything.

Senan: I remember years ago, you've prompted me to digress... so I did a lot of scuba diving when I was young...

Joe: Tell us about that. You were only jealous. [laughter] I just imagine you in one of those giant suits, like space suits made of copper, being lowered down from a ship to the depths. I'm sure it's slightly more modern than that. [laughter] And then the guys on the ship just take off and leave you there. [laughter]

Senan: We did different qualifications. For one of the qualifications I did, it was to prove that you wouldn't panic underwater if your mask got lost or flooded or whatever. You had to start at the surface with your scuba mask in your hand, so you'd know nothing covering your eyes, and you had to go down to the seabed and stop on the seabed and put your mask on and clear the water out of it. It was just to prove that you weren't panicking in that kind of a weird situation where you had no mask.

Senan: Anyway, the place that I had to do that test, the water was not very clear. There was a lot of silt in the water and the silt in the water was the same colour as the sand on the seabed. So there I am happily with my mask in my hand swimming down to find the seabed. Well I found it with my face. [laughter]

Joe: That explains a lot. [laughter]

Senan: I couldn't focus on anything because I had blurry vision because I just had water so I didn't actually see the seabed coming because it was the same colour as the water. Anyway, back to octopi. There were no octopi laughing at me that day hopefully.

Senan: Suckers. They have eight arms, all covered in hundreds of these highly sensitive suction cups. Not only are they sensitive to touch, but each one of them is actually a tongue. They can taste everything they touch.

Joe: Imagine having to taste absolutely everything. A large part of the outside of your body is covered in tongues. If one of those octopuses decided to wrap itself around your arm, would those suckers hurt?

Senan: I suppose that depends on how hard he wants to hold on. I don't think that they can tear a chunk of flesh off you just purely with the power of the suckers, but I think they probably could leave a mark on you alright, like a bruise or a red mark.

Joe: A love bite. A little octopus love bite for you. Or a hundred of them. [laughter]

Senan: It's weird, isn't it? Everything they touch they taste. And again it's another example of how sophisticated their nervous system must be, because they've got all the nerves that are coming from those taste buds back to their brains...

Joe: Maybe that's why they need the brains.

Senan: Maybe that is. Our nervous system is very centralised. We've got one brain, the spinal cord goes down the middle, all the messages go down the spinal cord from the brain out to your arm or your hand to tell it to grab that pint of beer and move it towards your mouth. The octopus don't...

Joe: They don't drink. [laughter]

Senan: Not alcohol anyway. They have a different system. They do have one central brain that kind of is where their consciousness resides, but each arm has its own little mini brain. And they have quite a bit of autonomy.

Joe: And the brain is actually located in the arm?

Senan: Yeah, I think it's in the upper part of the arm near where it joins onto the main body. Because they have somewhat gruesomely severed octopus arms to see what level of autonomy they have...

Joe: I prefer the story when it was severed by accident and then somebody observed it. But now they're severing them, they're actually cutting them off just to see what happens. This is like childhood level cruelty.

Senan: They have seen the arms continue to seek for food and try and pass food back to the place where the arm thinks the mouth should be and that kind of thing. They've even seen those severed arms respond to stimuli to being touched and so on.

Senan: They believe what happens is that say for example the central brain might give an instruction to one of the arm brains: search that cave for a crab that I'd like to eat. But the arm brain decides exactly how to go about the search, which muscles to move, interpreting what it can feel coming back from the taste buds and the suckers and stuff.

Senan: So it's interesting that you have this whole distributed consciousness that is not all in one place, it's almost like a committee deciding how to run the animal. Some experiments have shown that they don't seem to have a detailed awareness of where their arms are.

Joe: Maybe they do drink. [laughter] You can imagine one looking around saying, "Oh no, that's me".

Senan: But how did they know that? What did the surprise look like on a...

Joe: Oh, my arm. Oh, like they have an octopus version of Jesus, Mary and Joseph. [laughter]

Senan: I don't know how they carried out those experiments but apparently they did. I'm going to digress now into a book recommendation.

Joe: I'm going to count the number of times you digress now in this podcast right? That's two.

Senan: Children of Ruin by Adrian Tchaikovsky. He's a well-known science fiction author.

Joe: No relation to...

Senan: No relation to the composer and in fact he's not Russian.

Joe: To the plumber... to Super Mario.

Senan: He wrote a very interesting plot where octopi have evolved into highly intelligent creatures who have built their own spaceships and gone off to explore space. But then they meet humans and a large part of the book is about the difficulties in communication between the two species because he imagines octopus consciousness to be completely different to human consciousness because they're distributed around these nine brains instead of one central brain with the humans. Interesting book.

Joe: It's not a big stretch of the imagination to imagine that octopus consciousness is different than human consciousness. [laughter] I'm thinking there's definitely evidence for that.

Senan: Let's talk about their intelligence because that's where we came into this at the start, is that we know they're intelligent. First thing tool use, they're one of the creatures we've observed using tools, and that's considered to be a hallmark of intelligence. We've seen obviously humans, we've seen primates, monkeys, apes, dolphins, birds, elephants use tools, and octopus as well. The way they use tools actually displays a remarkable amount of foresight or planning about something that might happen in the future.

Joe: Theorising.

Senan: They've been known to collect old coconut shells and even dig them up deliberately. This would be near the shore where maybe coconuts have fallen in off trees and have rotted and all that's left is the shell or half the shell. They will collect those and carry them around with them, because they're anticipating they might need them as armour at some point in the future. If they then become threatened at some point in the future, they will draw themselves in underneath these old coconut shells they've been dragging around with them to protect themselves from being attacked by some predator.

Joe: This very nicely brings us back to this movie that you ruined for me. My Octopus Teacher. There is a bit in that where it took all the shells... basically there's a diver who makes friends with an octopus. That's the short version. And it's a beautiful story. You actually forget that the guy is holding his breath the whole time.

Senan: It's a beautiful fake story, go on.

Joe: Don't. He's going to destroy it twice. But at the time when you didn't know it was fake, when it came out and it was on Netflix and everybody watched it. Wow, isn't that amazing, we love the sea, that's a great story about the octopus. And you were like, they just had all these different octopuses that they get thrown into the water. Right, that one's dead. 57, bring number 57! It was just like every scene was a different octopus, and that just destroyed the movie. Now you can't do it again because it's destroyed already, so thanks very much.

Senan: I apologise for introducing realism.

Joe: Nobody wants realism anymore. Idealism. We want to fade back into idealism.

Senan: Like all good scientific theories, that theory of mine could have been wrong.

Joe: Maybe it was the same octopus.

Senan: No.

Joe: Not now because you're to say that story was fake now, wasn't it? Did you look it up afterwards that whole My Octopus Teacher was nonsense?

Senan: I mean it just didn't make sense to me that it could be the same octopus the whole time. Just didn't. For starters they have a very short lifetime.

Joe: You've just been talking for 20 minutes about how intelligent they are but you can't believe this dude made friends with an octopus off the coast of South Africa.

Senan: Well he might have for a week, but the one he met next week was a different one. Now with an entire camera team.

Joe: You're such a cynic. I will remain a dreamer.

Senan: Other signs of intelligence; navigation of mazes. In laboratories they've been seen to navigate really complicated mazes, make their way up all the blind alleys and eventually find the route that leads them to the food. And then tomorrow you introduce them to the same maze, they don't go into any of the blind alleys. They just go the shortest route directly to the food so they remembered exactly where the food is.

Senan: This is a funny one. I'd like to know how they actually did this, but somehow they've managed to get an octopus inside a jam jar with the lid on.

Joe: What?! I thought you said they could open jam jars from the outside. Not from the inside. Like a person opens it, you don't open a jam jar from the inside! I thought it was like they opened jam jars and the whole thing was that my god why would an octopus need to open a jam jar? Oh yeah, obviously if they're inside a jam jar. No, there's no way they put them inside a jam jar.

Senan: Somehow they got an octopus inside a jam jar. Maybe they put food in there...

Joe: I thought the only way that would actually happen in the wild is if another octopus put him in there.

Senan: Somehow they figured out how to unscrew the lid and get out again.

Joe: Who came up with that? Like okay, what are we going to do, I really need a research theory for my thesis. You know what we'll do? We've got some octopuses, we've got some jam jars. Let's just see where this goes. Oh my god. The world is a very strange place.

Senan: I wonder if they had used Kilner jars instead, you know those ones with a clip on the outside.

Joe: I bet you they could open it from the outside but there's no way they'd open it from the inside. That would be an octopus in a jar forever.

Senan: After a while they might discover they could break the glass with their beak.

Joe: Yeah, possibly.

Senan: That whole escape thing is a real... there's something about their psyche that leads them to want to escape from any confinement. I suppose that's the same as the rest of us. In aquariums it's a well-known thing that it's quite common for the animal keepers to come in the morning and find the octopus tank is empty again.

Joe: Yeah, I'm not surprised if they're putting them in jam jars. Bad enough in a jam jar.

Senan: They're really ingenious about escaping from the most well-secured tanks in aquaria.

Joe: And obviously the biggest thing to escape from is the air-filled room around the tank.

Senan: It's probably a bit late when they come to that realisation. They're also known to be able to recognise individual human faces. They'll get excited when certain humans appear and they run away when certain other humans with jam jars appear.[laughter]

Joe: Imagine the jam jar guys are not popular.

Senan: They can recognise individual people. It's incredible. And other signs, they've been seen to learn new things, new skills by just watching another octopus doing something.

Joe: Get out of the jam jar. Just stay away from the guy with the jam jar. I saw what happened to Fred.

Senan: They've been seen playing games. If one of these aquariums has a water jet coming into the tank and you give a few ping pong balls to the octopuses. Sometimes they'll throw them at the water jet, watch them come back out, throw them at the water jet again. They like playing games.

Joe: But do they get bored?

Senan: I'd imagine in a tank they must.

Joe: But do they get bored throwing the ping pong ball, or is it just like, oh my god, and two days later his arm fell off?

Senan: I don't know, there's a thesis for you, Joe.

Joe: There we go. Do octopi get bored. And how long does it take to bore the eight arms off of an octopus.

Senan: Also, they've been observed kind of twitching a bit when they're asleep. That might indicate that they're dreaming which again would be considered a sign of intelligence.

Joe: Has anybody thought of giving an octopus a piano?

Senan: If they're learning from other octopi.

Joe: They kind of learn new tricks really easy, and they have eight arms I mean this can only be a good thing. Octopi on pianos.

Senan: Are Steinways waterproof?

Joe: I imagine if they can escape for a couple of minutes...

Senan: If you put him in a jar?

Joe: Could you get a Steinway into the jar with him?

Senan: You put him in a jar. If they had a little mask with water in it. And then their arms were outside the mask. And sit them at a Steinway, see what happens.

Joe: That'd be reverse scuba diving gear.

Senan: Do you remember Rolf Harris's stylophone?

Joe: No.

Senan: That was a thing Rolf Harris years ago used to publicise, it was this tiny electronic keyboard thing with a stylus that you ran across the keys to make electronic piano-ish noises.

Joe: That's before my time.

Senan: It must be, yeah. I'm just wondering if that would be a better fit for the small little octopi than a great big long piano keyboard.

Joe: I think a big piece you can run along it.

Senan: Then again the Pacific octopus, the ones off western Canada, they'd be well able for it, they're like 8-foot long or something.

Joe: You can't get more Pacific than that.

Senan: I certainly can't. So very briefly because we're starting to run out of time. They are known to be able to edit their own RNA. What's RNA? DNA is like the master blueprint for how to build a creature, a human or an octopus or whatever. To actually build something from the plan, it's first converted by our bodies into a copy called RNA. RNA is like a photocopy of a bit of the DNA that's relevant to whatever the task in hand is. It's the RNA that's actually used to do the building of whatever needs to be built.

Joe: Does RNA build specific small things or RNA can build a whole creature?

Senan: Now we're getting into the weeds here, so I don't have a definite answer to that.

Joe: Okay, reverse, reverse. I rescind my question.

Senan: I think what's done typically is a snippet or photocopy of a piece of the DNA, not a photocopy of the entire master plan. If our DNA needs to change because something in our environment has made it hard for us to survive, it takes lots of generations for some mutation to occur that allows us to solve that problem. That's basically how evolution works.

Senan: But these guys are able to edit their RNA on the fly in response to short-term changes. Mostly not in generations after generations, but in one creature. It's been observed that if they have to go and live in water that's significantly colder or warmer than what they were living in, they will make some changes to their RNA to change their blood chemistry to cope better with the warmer or colder water.

Joe: Where is the point that that is just a natural reaction versus a change to the RNA? They have to kill them and photograph their RNA...

Senan: How do they detect it, I honestly don't know, but there might be some unpleasant things happening in the lab alright.

Joe: Bring number 57! [laughter]

Senan: Now we come to the sad part of the story.

Joe: Wow. And it's been very sad so far.

Senan: Why haven't octopi taken over the world if they're so smart?

Joe: Maybe they have.

Joe: Maybe they have been in charge for ages and they're just going, we're just going to let these guys wipe themselves out.

Senan: A bit like the mice in Douglas Adams's stories. Remember that one, no? It turns out that the mice were an alien species that the Earth was a supercomputer and the mice developed this supercomputer to work out the answer to life, the universe, and everything. I remember the answer, I don't remember the mice.

Senan: 42 wasn't it. Good old Douglas Adams, pity he's gone. Anyway, we digressed again. The sad thing is they only live about, well slightly different for different species, but typically in the region of about three years they tend to live. They reproduce once only and they die immediately after or very soon after reproducing.

Senan: In the case of the males, very soon after mating they die. They have this optic gland that releases some kind of chemicals into their system that starts to degrade their bodies almost immediately after they've mated.

Joe: I wonder if they stayed celibate. Would they just keep going? I'm not doing that. I see what happens to everybody else. I'll learn from watching what happens to other people. No, not for me.

Senan: Maybe there is out there some immortal octopus that has been celibate and very frustrated for the last 600 years. In the case of females it's arguably sadder because once they lay their eggs they actually stop hunting and feeding and they just obsessively guard their eggs until they starve themselves to death.

Joe: That is the saddest thing.

Senan: It's shocking. But it also means that, and this might be the answer to the question about why octopuses have not taken over the world; it also means there's no parental generational transfer of knowledge. Every single baby octopus has to learn about the world from scratch themselves. They're starting again. There's no parents to teach them anything. There's no handing down of old knowledge, of old skills. Imagine if they could do that, what they could have achieved with the intelligence they have.

Joe: But there must be some evolutionary reason why they just wiped them...

Senan: There's all kinds of theories. One is there's a very high predation rate, like octopi, very few of them survive into adulthood because they're essentially defenceless with their soft bodies if they can't hide. So one theory is that they put all of their resources into one reproductive splurge, because they might not get another chance, something might eat them before they get another chance. Again, none of these theories are proven.

Senan: There's another kind of darker theory that says it might help avoid the risk of parents cannibalising their own children.

Joe: Well that's always good.

Senan: Before you get hungry, surely though that risk would be lessened by allowing the mothers to eat!

Senan: Perhaps, but anyway the mothers tend not to eat unfortunately. So yeah, I mean that's the sad end to the remarkable story of octopi. They're amazing creatures.

Joe: I'm going to think twice about ordering them on a menu.

Senan: Oh my god, why did you put that picture into my head? And with that folks I'm resigning from this podcast.

Senan: Until next time, it's goodbye from Senan.

Joe: Thanks for listening. This is Enough with the Science, I'm Joe.