SPEAKER_00: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising.
SPEAKER_01: As promised, it's time for our second bonus podcast for you, episode two of 30 Animals That Made Us Smarter, also from the BBC World Service. Over to Patrick Ihe.
SPEAKER_02: When it comes to cool animals, I've got to say the octopus is hard to beat. They have three hearts. Blue blood can grow back their arms, squirt ink to deter predators and being boneless, they can squeeze in and out of the smallest spaces. Still not impressed? Well, when it comes to trickery and deceit, these are the masters of disguise. They can not only change their colour, but also the texture of their skin to match their surroundings. I mean, how clever is that? When they're done with swimming and want to take a break, they just settle down and without even waving a magic wand, they can change their skin and simply disappear. Then when their unsuspecting prey passes by, they can pounce with the greatest of ease. Ingenious. But also kind of creepy. I mean, imagine if we could do the same thing, change our clothing to match our surroundings. It would be a pretty cool trick to play at a party, but in a world of increasingly sophisticated surveillance and counter surveillance, the race to unlock the secrets of the octopus could have very high stakes indeed. I'm Patrick Ihe and this is 30 Animals That Made Us Smarter from the BBC World Service, a brand new podcast that investigates the amazing things that animals have taught us. I really hope you enjoyed the first episode about the Kingfisher and the Bullet Train. Thank you so much for all of your comments so far. And because this is a new podcast, remember, I really want to know what you think. Please help me spread the word and where you can leave ratings and reviews. And on social media, the hashtag is 30 animals. So let's crack on because in this number two octopus and camouflage, we'll be hearing how cephalopods that's octopus, squid and cuttlefish to you and me are inspiring some very impressive camouflage. And I mean, really impressive. Cephalopod literally means head foot in Greek, and refers to how these animals are basically a head attached to a foot, a mass of sucker bearing tentacles. But don't be fooled. They are a highly intelligent group of ocean dwelling creatures, which include the eight armed octopuses or octopodes, squid, cuttlefish and nautiluses. They come in all shapes and sizes. The giant squid at about six times the length of the bed is the largest, whereas the smallest ones like the pygmy squid could sit on the end of your finger. Cephalopods are found in all the oceans of the earth. And like many of us prefer the warmer climes with the greatest diversity seen nearest the equator, which decreases as you get closer to the poles. Now, here's a few cool facts about cephalopods. When it comes to getting about they use a method of jet propulsion, much in the same way that a jet ski works, strong muscles fill the body cavity with water and then expel it through a funnel, which propels the animal in the opposite direction. But not only are they nimble, they are highly intelligent too. They have the largest brains of any invertebrate, that's animals without backbones. They have good memories and can learn by watching or through trial and error. Cephalopods are cunning predators, proficient stalkers, excellent ambushers, and as I've mentioned, masters of disguise. Take the mimic octopus, for example. It can change its skin color, stretch out its arms, and before you know it, you think you're staring into the face of a venomous lionfish or a seething mass of deadly sea snakes. It's a great way to speak of any potential predators. And then there's the infamous and extremely venomous blue-ringed octopus. You can find them nestled away in tide pools in the Pacific and Indian oceans from Japan all the way down to Australia. When these small octopuses are provoked, luminous blue rings start appearing all over their bodies and there's no mistaking what this means. Like a flashing beacon, this is a very clear warning signal. Stay away. I don't taste good and I'm venomous. You'd better leave me alone. So, the six million dollar question, I know what you're thinking. How do they do it? How do octopuses change their color? Well, just below the surface of the skin are thousands of color-changing cells called chromatophores and it's these cells that are responsible for their amazing transformations and this is how they work. Imagine you're holding a balloon of colored dye. As you gently squeeze the balloon, the color is pushed up towards the tip, stretching the balloon and making the color appear brighter as it draws nearer the surface. The chromatophores work in a similar way. The center of each cell contains a sac filled with either black, brown, orange, red or yellow pigment. By expanding or contracting these cells, they push pigment to the surface of the skin and change color in the blink of an eye. As well as chromatophores, some cephalopods have other color-changing cells which produce iridescent greens, blues, silvers and even golds and some can reflect back the colors of their surrounding environment, making the animal less conspicuous. Now, as I mentioned earlier, it's not just the color of their skin that octopuses can change, they can also modify their texture. It's amazing to watch as they move across the ocean floor, they can literally change their skin texture to match objects like smooth rocks or spiky coral all within moments of each other. They do this by adjusting the size of projections on their skin called papillae which result in anything from small bumps to big lumpy spikes. Suffice to say, never try playing hide and seek with these guys, you will lose. As you can imagine, all this color-changing trickery has attracted quite a lot of interest in the human world to create what could be not only colorful but highly useful surveillance technology. Our first example comes from a collaboration between the Universities of Houston and Illinois in the United States of America who were inspired by the color-changing octopus to develop a material which I like to think of as a sort of flexible skin that can read its environment and mimic its surroundings. This skin is made of thermochromatic materials, materials that respond to a change in temperature by changing in color. Like the very first TV sets, the team's prototypes work in black, white and shades of gray but their hope is to eventually develop a color version. They're starting small with a skin only a couple of square centimeters in size but this could easily be scaled up. It's made up of ultra-thin layers containing a variety of sensors, reflectors and color-changing materials which work together so that like our octopus, the material changes to match the color of the background. So what's involved? Well the skin is like a monster sandwich and I really love sandwiches so let me walk you through this one. The top layer contains a temperature-sensitive dye that appears black at low temperatures and clear at temperatures above 47 degrees Celsius. Then there's a layer of white reflective silver tiles. Next an ultra-thin layer that controls the dye's temperature and finally a transparent silicone rubber foundation. Altogether our sandwich measures less than 200 microns thick at about the same thickness of two sheets of paper. It's not going to fill you up. But there's more. Underneath is a base layer containing light detecting sensors so that it knows how and when to change color and the skin can do all of this within just one or two seconds. Now I genuinely think this would make for the world's ultimate party outfit. Just think about it, you could change the color of your clothes as you move between rooms. Or imagine a color-changing shape that makes you look like a shape-shifting wetsuit which underwater lets you watch animals unnoticed and then transforms you into a sun-kissed muscle-bound Adonis when you get out. Finally that beach body I've always wanted. Now that would be cool. But the researchers have rather less frivolous ideas. A skin like this could be really useful in surveillance and military applications. For example you could use it to reduce a robot's visibility making it easier to access and explore dangerous areas. Not only does this avoid human lives being put at risk but also offers the robot better protection too. And being able to camouflage robots like this could also be useful when it comes to studying animals in their natural habitat. Not only could you get closer but you'd also avoid having your expensive research robot being attacked or damaged. And it doesn't stop there. A different team this time from Harvard University in the USA led by George Whitesides have created a soft color-changing robot that can either stand out or blend in with its surroundings. Like our Octopus the robot has a soft rubbery body and can crawl and bend under obstacles. They designed their original soft robot back in 2011. It was made from silicon-based materials and it moved when air was pumped through tiny cylinders into its forearms. The design has since been modified and now the robot can disguise itself. A network of tiny channels a bit like our blood system runs through a skin-like layer which covers the robot. As different dyes are pumped in the robot quickly changes color. Hot or cold fluids can be pumped into the robot's body so they can be thermally camouflaged, making them extra stealthy even against infrared detection. But what if you want it to act as a rescue beacon? Easy. Instead pump in fluorescent fluids and watch them glow in the dark. At the moment the fluid is still pulled in from a separate reservoir
SPEAKER_02: but in the future this reservoir could be incorporated into the robot's body. A color-changing robot could be useful in situations where you don't necessarily want them to stand out like in public spaces. But clearly the idea of a camouflaged robot would be useful in civil and military surveillance. There's still some way to go before many of these ideas are exploited commercially but I'm sure you'll agree this is a very exciting area of technological innovation and one we should probably keep our eye on. That's if we can. In number three of 30 Animals That Made Us Smarter, an original podcast from the BBC World Service, we'll be hearing how the bite of a mosquito is helping to design a surgical needle that's pain-free. I hope you like the podcast and please let us know what you think and spread the word. It's hashtag 30animals on social media. And of course do check out our website. It's bbcworldservice.com slash 30animals where you'll find a list of information sources for this episode and also if you haven't already seen it, our fabulous animation of the Kingfisher morphing into a bullet train. Thanks for listening.
