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SPEAKER_04: Hello, it's me, Tim Harford with our final bonus episode for you have 30 animals that made us smarter from the BBC World Service. I love the idea of this brand new series because it brings together some amazing ideas and inventions, some of which are economic success stories with remarkable animals. This is the last time you'll get a chance to download it here. So if you want to carry on listening to it, I sincerely hope you do. Now's the time to go and find it. It's 30 animals that made us smarter. You should be able to get it simply by searching for 30 animals wherever you found this podcast. And please remember, if your podcast app allows subscribe, that'll mean you'll get every episode automatically. And just as I frequently beg you to rate or review 50 things that made the modern economy, I hope you'll do the same for Patrick and 30 animals too.
SPEAKER_02: Have you ever been in a crash? Not necessarily a car crash. You might have fallen off your bike, bumped into a door or had someone bash into you whilst playing a sport like rugby. It hurts, doesn't it? The human body is a wonderful thing, but we're only able to take impacts up to a certain level before we bruise, break, get concussed or worse. But as the world speeds up, as planes, trains, cars and even bicycles get faster, these kinds of impacts will also get bigger and we'll need better ways to deal with them when they come. Now this has got to be one of the most recognisable woodland sounds. It seems to reverberate amongst the trees. It's hard to believe that it's made by a bird, a woodpecker drumming its beak against the trunk of a tree. But there's more to this sound than meets the ear. Because in the future, we could have the head-banging antics of the woodpecker to thank for better tech when it comes to dealing with crashes. Be that the survival of flight recorder data from the wreckage of a plane crash or better designed crash helmets for us humans. Welcome back to 30 Animals That Made Us Smarter, an original podcast from the BBC World Service, which reveals how animals like the kingfisher, octopus and mosquito, which featured in previous episodes, have been helping us humans out with some really challenging design problems. This is called biomimicry and I'm fascinated by this stuff. I'm Patrick Ihe by the way and if you know of a great biomimicry story then do get in touch. And you never know, we might even feature your story in one of our podcasts later on in the series. Email us at 30animals, that's three zero animals, at bbc.com or you can contact us on our website bbcworldservice.com slash 30animals where you'll also find our privacy notice. Now, back to that drumming woodpecker. In this number four, woodpecker and black box, we'll uncover the link between the forest headbangers and the survival of a plane's flight recorder which records audio and data during a flight and helps investigators in the event of an accident or crash. Woodpeckers belong to a family of birds which also includes birds called piculets, rhinex and sapsuckers. Piculets include the smallest at about seven centimetres in length, which if you're an adult is the same length of your thumb. Whilst the great slatey woodpecker can grow up to 50 centimetres or more in length, which is longer than my forearm, the imperial woodpecker and ivory woodpecker were even bigger. But as there have been no sightings in recent decades, they're generally believed to be extinct. Woodpeckers are found in many countries across the globe, including South Africa, India and Nigeria. And whilst most are forest and woodland birds, there are a few exceptions. Take the Gila woodpecker for instance. It's found in deserts where it nests in trees or giant cacti in parts of the Southwestern United States and western Mexico. Woodpeckers, as their name suggests, spend much of their time pecking at wood. Clinging vertically against the tree, they rapidly hammer the bark in search of food like insects and grubs. They can also drill holes into dead or dying trees where the wood is slightly softer to create nests. These are like little caves hollowed out inside the trees. And finally, woodpeckers don't just use their beaks or bills to peck, they also drum. They drum to communicate with other woodpeckers, to stake their claim to territories and to attract a mate. To get the best, loudest sound, they need something with really good resonant qualities. They'll drum on trees, wooden telegraph poles and even on metal poles in order to make the loudest sound possible. If you hear them drumming rather than pecking, you know they're not looking for food or drilling a hole, but making a loud, bold statement. This is my patch. So how do they do all of this? Well, as you'd expect, they have strong chisel-shaped bills which are very good for drilling into wood. They also have very long, sticky tongues for extracting insects and other food from bark. Their stiff tail and grasping toes help to keep them secure on tree trunks. But the key is the way they can bash their head against a tree up to 22 times a second, which is ridiculously fast, without doing themselves any damage. Imagine the mess you'd make if you tried it yourself. So you need to understand something called g-force. This is a gravitational force that acts on objects as they move through space. We particularly feel it when we increase our speed or decrease our speed. G-force is helpfully measured in Gs. The more Gs there are, the stronger the force. And we can only take so much of it. So that plane taking off is just under 2 Gs. That's fine. A very fast roller coaster would very briefly max out at around 5 to 6 Gs, which is roughly what a Formula 1 driver would experience when they slam on the brakes really hard. It's complicated and depends a bit on where the force is applied and for how long, but basically humans tend to pass out if they experience 6 Gs for a sustained period of time. But we can handle sudden impacts to the head of about 80 Gs before getting concussed. Well, a woodpecker's head experiences around 1,200 Gs as it drums on a tree. That is beyond impressive. How does it do it? Well, in order to withstand over 1,000 times the force of gravity, a woodpecker's skull is designed to absorb shock and minimize damage. A bit like a sponge, the skull can compress and expand. The bone that surrounds the brain is thick and spongy and packed with something called trabeculae, which are a bit like microscopic plates. And this forms a tightly woven mesh which provides support and protection and stops low frequency vibrations from passing through. It's essentially armour for the brain. Woodpeckers also have a highly adapted hyoid bone. In humans, the hyoid serves as an anchor for the tongue. It's tucked away at the root of the tongue in front of the neck between the lower jaw and the voice box. In woodpeckers, this solid springy bony support is much longer and forms a loop around the entire skull which acts as a safety belt for the brain. The brain itself is small and smooth and held in a tight space so it doesn't move around too much, unlike our brain which is surrounded by fluid. When the woodpecker's brain does collide with the skull, the force of this impact is spread out over a larger area. This makes them far more resistant to concussion. A woodpecker's beak also helps prevent trauma. It's extremely strong and doesn't fracture or bend. So let's just recap. We now know that woodpeckers have four shock absorbing features. The first is a hard but elastic beak. The second is the hyoid, a springy tongue supporting structure that extends behind the skull. Third, an area of spongy bone in its skull. And finally, a skull design which suppresses vibration. So it should come as no surprise that woodpeckers and their shock absorbing capabilities have attracted a lot of interest. Sang Hee Hoon and Sang Min Park at the University of California in Berkeley in the United States of America wanted to protect electronic devices like flight recorders on board planes from the damage caused by high impacts. They studied video and CT scans of the head and neck of the gold-fronted woodpecker to identify the areas that absorb mechanical shock. They used these as a blueprint to build a mechanical shock absorbing system to protect microelectronics that works in a similar way to the woodpecker's skull. They started out with a cylindrical steel metal enclosure which mimicked the beak. Then they added a layer of rubber within the cylinder which mimicked the hyoid. They replaced the spongy bones with glass beads in which the sensitive electronics were placed. And finally, they added a second layer of metal to protect the microelectronics. Hoon and Park then placed their system inside a bullet and used an air gun to fire it at an aluminium wall. In their tests, the electronics were protected against shocks of up to 60,000 Gs. Today's flight recorders can only withstand shocks of about 1,000 Gs so the design could offer much greater protection. Studies of the woodpecker might even feed into motorsports like Formula 1 where the challenge is getting drivers to decelerate in an accident in such a way that their internal organs remain intact. I'm obsessed with Formula 1 and I remember watching on television Fernando Alonso's horrifying crash in Melbourne, Australia in 2016. His car made contact with another one at 305kmh and then barrel rolled through the air before crashing into the barriers. He experienced three high G decelerations, one at 45g, one at 46 and a final 20g load for good measure. Miraculously, thanks to neck and head support systems, sophisticated seat belts and a cleverly designed cockpit, he was able to walk away with his life. The hope is that newer and even better ideas may come about from this area of research. But away from the racing track and back on the
SPEAKER_02: public roads, the woodpecker has inspired a keen cyclist. Aniruddha Surubhi was riding his bike through London, England when he had an accident. He was wearing a helmet at the time but it cracked and he was rushed to hospital with concussion. At the time of the accident, Surubhi was doing a Masters degree in design at the Royal College of Art and was looking for a project for his final year. Suddenly he had his answer. Design a better bike helmet. Once again it was the woodpecker that came to the rescue. Surubhi was particularly interested in the hyoid bone and how it wrapped around and over the top of the skull like a natural seat belt. And then there was the flexible spongy cartilage which acts as a shock absorber against repeated blows. He began building versions of his design using different materials starting with glass, then rubber and ending up with cardboard. After hundreds of lab tests of each material, he finally settled on cardboard. But this wasn't just any old cardboard. He designed a special dual density cardboard with an internal honeycomb structure. To construct the liner, he laser cut ribs out of honeycomb cardboard and assembled them into an interlocking helmet shaped lattice. The lattice was designed with more give, more flexibility than the commonly used polystyrene foam liner so that the flex would soften the blow and air pockets inside each individual rib would absorb the impact as well. All with the aim of offering better protection to the head of the person wearing the helmet. In lab tests, the cranium liner as he called it, not only performed well at absorbing force, but because the liner was 90% air, it was also light and recyclable too. Sue Ruby has since worked with a number of people to bring the liners and the helmet to market. So, next time you hear a woodpecker drumming, just think how this bird's head banging has inspired designs to make the world a safer place. In number five of 30 Animals That Made Us Smarter, an original podcast from the BBC World Service, we'll be discovering how the technique which bats use to navigate in the dark could assist blind people. And it's all to do with some ingenious tongue clicking. You can find a list of sources of information for this episode on our website, www.bcworldservice.com. Where you can, please leave ratings and reviews. We rely on you to recommend us. And please do send me your comments. The hashtag on social media is 30 Animals. Don't forget, you can also subscribe to our podcast. It's free and it means you'll get every episode automatically. Now, where did I put my cycling helmet?
