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Hank: If you've ever heard or seen anything about dinosaurs lately except for a certain popular movie franchise, then by now you probably know that at least some dinosaurs had feathers. That's been an established scientific fact for a long time, nearly 20 years, and we've had some idea that they probably had feathers for much longer than that.

Paleontologists are still trying to figure out exactly what kinds of dinosaurs had feathers and what they looked like, but at least one entire class of dinosaurs seems to have had them - including Velociraptors, and probably Tyrannosaurus rex. As early as the 1800's, experts in animal anatomy were noticing the similarity between dinosaurs and birds.

Thomas Henry Huxley, a scientist who was one of the earliest advocates for evolution, pointed out that the dinosaur Compsognathus looked a lot like Archaeopteryx, which was at the time was thought of as the first bird. And part of why Archaeopteryx was considered to be a bird was because it was fossilized with an unmistakable impression of feathers.

Feathers are made of protein, which tends to break down before it can fossilize. That means that even dinosaurs that did have feathers aren't usually discovered with them intact. But lately we've been turning up all kinds of feathery fossils, especially in China, where the geology is just right for preserving feathers. You can see the impressions of them preserved around the dinosaur or in an imprint of its skin. And over the past two decades, paleontologists have been working on studying them.

The first feathered fossil to make a big impact was discovered in 1996. It was of Sinosauropteryx, a type of dinosaur called a theropod that was two-legged, carnivorous, and eventually gave rise to birds, and the fossil clearly had a halo of fluff around it. The fluff was made of simple feathers. A bird's more complex flight feathers are rigid and have a central spine called a vane. But this fluff, which paleontologists for real call dinofuzz, has a simpler structure, so Sinosauropteryx couldn't fly. Instead, it probably used its feathers to attract mates or keep warm or both.

But even though we don't know exactly how Sinosauropteryx used its feathers, we actually do know what color they were. Sometimes you can see the structure of fossilized feathers in a microscope - including the tiny structures responsible for color. Colors like blue or yellow don't last for millions of years as far as we know, but red and black do because the cellular structures that hold red and black pigments have distinctive shapes, and in really good fossils those shapes can be preserved. Using an electron microscopes, scientists can tell Archaeopteryx had black and white feathers, and that Sinosauropteryx had reddish and white stripes. Since Sinosauropteryx, there's been a never-ending parade or fluffy dinosaurs, some of them have simple dinofuzz, but others have feathers that start to look a lot like the flight feathers of birds. 

There have been so many, in fact, that it seems like all theropod dinosaurs had some form of proto-feathery fluff. Even some dinosaurs unrelated to the theropods had very simple protein fuzz which could mean that the common ancestor of all dinosaurs had it too. The theropod group includes two of pop culture's favorites - the Velociraptors and Tyrannosaurus rex. Now I'm not here to burst anybody's bubble or you know, criticize any movie makers, but Velociraptors definitely had feathers. 

In the summer of 2015, paleontologists discovered a dinosaur very closely related to Velociraptors but better preserved than any Velociraptor found so far with big wing-like feathers on its arms. Because it's so closely related to the Velociraptor, they imagine it was very similar. They say it paints a picture of the Velociraptor as a fluffy, feathered poodle from hell. We've yet to find a Velociraptor fossil with its feathers intact but between the presence of feathers on its relatives, and the points on its bones for feathers to attach, it almost certainly had them. 

As for whether the T. rex had feathers, it's a little less clear. Some Tyrannosaurus earlier on the evolutionary tree definitely had dinofuzz, but the T. rex has something in common with elephants and rhinos - it was huge. And even though the ancestors of elephants and rhinos had fur, modern-day versions don't have fur anymore because they're so big, they don't need it to keep warm. That logic might also apply to something the size of T. rex. It could've lost the feathers its ancestors had since it was so big, it didn't need the fuzz to keep warm.

In fact, in 2012, scientists turned up a dinosaur called Yutyrannus. It was closely related to Tyrannosaurus, was really big, and had simple feathers, so T. rex might have had them too. But until we find a T. rex with impressions of its skin, we can't be sure. But we definitely do have to change our picture of the dinosaur age to include some fluffy hell poodles. 

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