Why did feathers evolve?

0:46 Welcome to Science Is Not Boring by kidopoly.com. I'm Mira. And I'm Finn. Before we start, we have some huge shout-outs. A big hello to Maxine, who is seven, and her brother Alden, who is four. They love parrots and asked us exactly how they get their beautifully coloured feathers.

1:04 That is an awesome question. And a huge, happy sixth birthday to Grace in Sydney, Australia, who is celebrating her birthday today.

1:13 Happy birthday, Grace! And a big hello to her big brother Harry, who is eight, and can solve a Rubik's Cube in under 38 seconds.

1:22 Whoa, 38 seconds? I can't even solve one side in that time.

1:27 If you haven't already, tap follow wherever you're listening so you never miss an episode.

1:31 Okay, Mira. Maxine and Alden want to know about parrots. Are we talking about feathers today?

1:37 We are! Did you know that a parrot's feather is actually a microscopic light bending factory that creates colours out of thin air? Wait, out of thin air? How does that work? We are going to find out. But we aren't just looking at modern birds. We are travelling back 160 million years to discover why feathers evolved in the first place, long before any bird ever took to the skies.

2:02 Wait, if feathers didn't start out for flying, what were they for? We will get there! First, let's look at Maxine and Alden's question. A parrot's bright red, orange, and yellow colours come from a totally unique set of pigments called citychofulvins.

2:21 Citico fulvins? That is a mouthful.

2:25 It is! Unlike flamingos, which turn pink from the food they eat, parrots actually build these citico fulvin pigments inside their own bodies, right as their feathers grow.

2:37 That is so cool! But wait, parrots are famous for being green and blue too. Do they make blue pigments?

2:45 Nope. There is almost no true blue pigment in nature. Parrots get their blue from microscopic physics. Inside the feather, there is a spongy layer of keratin, which is the same type of protein our fingernails are made of.

3:01 Ew, I'm picturing birds covered in tiny fingernails now.

3:06 It is much softer. That spongy layer has microscopic holes that bounce the light around. When white sunlight hits the feather, the structure scatters the light, reflecting only the blue waves back to our eyes.

3:21 Oh I get it. So if a parrot has a blue structure but adds that yellow citico folvin pigment on top, blue and yellow make green.

3:30 Exactly! The feather is literally a tiny optical illusion mixed with a chemical laboratory. There are five known types of sitychofulvin pigments, and parrots mix them to make all sorts of vibrant colours. That is genius!

3:47 Okay, but you said we were going back 160 million years. Did ancient parrots invent these feathers? Not parrots, dinosaurs. Dinosaurs had feathers. I thought they were all scaly and green.

4:01 For a long time, everyone thought dinosaurs were just giant scaly reptiles. But in 1861, everything changed in a limestone quarry in Solnhofen, Germany.

4:14 What did they find in Germany?

4:16 Workers were digging up smooth stone and they cracked open a rock to find the perfect fossilised imprint of a single asymmetrical feather. It was 150 million years old.

4:30 Just one feather from 150 million years ago.

4:34 Yep, but shortly after they found almost an entire skeleton. The German paleontologist Hermann von Meyer named it Archaeopteryx.

4:46 Archaeopteryx? Was it a bird or a dinosaur?

4:51 That was the huge puzzle. It was about the size of a modern raven, roughly 20 inches long. It had broad wings and flight feathers, just like a bird. Okay, so it was definitely a bird. But wait! It also had a jaw full of sharp little teeth, three fingers with sharp claws on each wing, and a long, bony reptilian tail.

5:16 Whoa! Birds today don't have teeth or long bony tails. It was like a crazy mashup.

5:22 Exactly! Archaeopteryx was the missing link between dinosaurs and birds. It proved that birds evolved directly from small, meat-eating dinosaurs called theropods.

5:35 But if Archaeopteryx had wings, it used feathers to fly, right? Does that mean feathers evolved just for flying?

5:42 That is exactly what scientists thought for over 130 years. They assumed feathers and flight were invented at the exact same time. Until 1996, when an amazing discovery in China flipped paleontology upside down. What happened in China? In a place called Liaoning, scientists found a fossil of a small, fast-running dinosaur named Sinosauropteryx.

6:10 It lived 125 million years ago, was about 3.5 feet long and weighed just over one pound.

6:18 One pound? That is tiny. Was it scaly?

6:23 No! The fossil was surrounded by a halo of what scientists call proto-feathers. They weren't complex like parrot feathers. They looked like simple downy fuzz or hare.

6:35 A fuzzy dinosaur? But it couldn't fly, right? Its arms were too short.

6:40 Spot on! It definitely could not fly. So if a land dinosaur has feathers, it means feathers did not evolve for flight.

6:56 Oh wow! Like a built-in winter jacket. So feathers were invented just to stay warm.

7:02 Warmth was the first reason, but there was a second reason, and we learned about it from another feathered dinosaur called Ancyornis, which lived 160 million years ago. What was Ancyornis using its feathers for? Display! In 2010, the scientist Jacob Vinther looked at Ancyonis fossils under an electron microscope.

7:25 He was looking for microscopic colour sacs called melanosomes.

7:30 Wait, he could actually see what colour the dinosaur was.

7:33 Yes! Sausage-shaped melanosomes mean black or grey, and meatball-shaped ones mean reddish brown. Vint approved Ancyonis was covered in bold black and white stripes with a bright red fluffy mohawk on its head.

7:48 Haha, a punk rock dinosaur! That is amazing!

7:52 Exactly! Ancyonis was showing off! Its bright stripes and red crest were like billboards, used to attract mates or scare off rivals.

8:02 So feathers evolved first as warm fuzzy coats, then they became bright, colourful billboards. And only much later did some dinosaurs use them to glide and fly.

8:13 You nailed it! Dinosaurs were walking around in fluffy, colourful plumage, tens of millions of years before birds ever took to the sky.

8:23 That completely changes how I picture a T-Rex. Do we have any other mind-blowing facts about feathers?

8:30 Oh, plenty! Remember those cytacofulvin pigments in parrots we talked about earlier?

8:35 The citacofulvins, right? The ones that make red and yellow.

8:40 Yes! Well, scientists recently discovered those pigments do not just look pretty. Red parrot feathers with lots of cytacofulvin actually resist a feather-eating bacteria called Bacillus lyceniformis.

8:56 Ugh, feather-eating bacteria? That sounds so gross!

9:02 It is a little gross, but the red pigment acts like an armour, protecting the keratin in the feather from breaking down.

9:10 So the colour is literally a shield. What about that striped dinosaur, Ancyonis? Any weird fact about him?

9:18 Ancyornis was about the size of a pigeon, but it didn't just have two wings. It actually had long flight feathers on its arms and its legs. It was a four-winged dinosaur. Four wings?

9:32 That is wild! Dinosaurs were so much weirder and cooler than I ever thought.

9:37 Alright, Finn, it is time for the quiz. Let's see how much you and our listeners remember about our journey from modern parrots back to fluffy dinosaurs.

9:47 I am ready. I've got my thinking cap on and my feathers ruffled. I hope I don't get the confusing dinosaur names mixed up.

9:55 You will do great. Listeners at home, you can play along too. Shout out the answers if you know them. First question. What are the special red and yellow pigments that parrots make inside their bodies called? Next one. In what year was the famous Archaeopteryx feather discovered in a limestone quarry in Germany?

10:24 Question 3. What was the main reason the tiny dinosaur Cinosauropteryx had a coat of fuzzy proto-feathers? Here is number four. In 1996, the fuzzy Sinosauropteryx was discovered in Liaoning, which is located in what country? Last question. Which dinosaur had its colours revealed by microscopic melanosomes, showing it had black and white stripes and a red mohawk?

11:05 Great job! Let's see how you did. The first answer is those special parrot pigments are called Cetacofulvins. For question two, the famous Archaeopteryx feather was discovered in Germany in 1861. Number three, the answer is Cinosauropteryx used its downy proto-feathers for warmth, like a winter coat.

11:31 Question 4. That incredible fossil was discovered in China. And the final answer is the four-winged punk rock dinosaur was Ancyornis.

11:42 I got most of those. I still can't get over the fact that dinosaurs were basically giant, colourful, fluffy birds running around. That is the coolest thing I have learned all week.

11:53 I know, right? It totally changes how you look at a pigeon today, doesn't it? They are basically tiny, modern dinosaurs just walking around our parks.

12:03 Listeners, if you loved learning about fluffy dinosaurs, please leave us a five-star review and tell us which feathered dinosaur was your favourite. Just scroll down and tap the stars.

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12:24 Want your name on the show? Send us an email at hello at kidopoly.com.

12:30 Thank you so much for exploring the ancient world with us today. See you next time on Science Is Not Boring. Bye everyone.

12:38 Keep looking up and stay curious.