Feathered dinosaurs

If you wanted to know what a dinosaur looked like, the first place to look would be the Jurassic Park/ Jurassic World movies. They have made extinct dinosaurs real and even, to some extent, lovable. If Jurassic Park/ World theme parks were real and safe, it certainly looks like a very appealing place to visit. Dinosaurs are majestic creatures; the giant Brontosaurus, the vicious Tyrannosaurus, the nimble Velociraptor and others, have captured the imaginations of many. But were dinosaurs really like the ones shown in the movies? Were they covered in tough scales like crocodiles?

Since the early 2000s, a number of newly found dinosaur fossils showed something that shocked us all. These dinosaurs had feathers. How do scientists know that dinosaurs had feathers? Bones can be preserved for a long time, but soft tissue degrades rapidly. Dinosaurs lived 150-250 millions of years ago and that's a long time for tissue to degrade. Well, sometimes we get lucky, and find a very well-preserved fossil, usually preserved in stone. While the actual feathers are not present any more, traces of feathers can be seen engraved in stone. Feather shafts, which are the stiff middle vein of feathers, have a good chance of withstanding decomposition, and that's what we see in fossils today.

Here are a few examples of what feathered dinosaur fossils look like. These are 2 recently discovered dinosaurs. On the left is Zhenyuanlong suni. This was found in the Liaoning province in northeast China. This region has been a hotspot for finding feathered dinosaurs. Like most of the dinosaurs found in this region, Zhenyuanlong suni is not big. It is about 1.5m long, roughly the size of a large dog. However this is big compared to the other dinosaurs in the region, which are closer to the size of a cat.

Adapted by permission from Macmillan Publishers Ltd: Scientific Reports doi:10.1038/srep11775 and Nature (doi:10.1038/nature14423), copyright (2015)

This fossil is in a very good shape and all the limbs and tail are intact. What is interesting is that the imprints of the feathers are preserved. The brown regions around the skeleton (top left) show where feathers once lay, on the wings and tail. In the closeup of the arm (bottom left), you can take a better look at the spots where feathers were. Zhenyuanlong suni had arms which were completely covered with long feathers. Although still up for debate, Zhenyuanlong suni most probably was not able to fly.

On the bottom row lies Yi qi, another dinosaur found in China. This was unearthed in Hebei province, also in northeast China. Named for its wings, Yi qi literally translates into bizarre wings. Compared to Zhenyuanlong suni, elements in this fossil are harder to see so let me walk you through why its wings were deemed bizarre.

Once again you can see straight lines radiating from the bones (top right). They were Yi qi's  feathers. Feathers are found on the head, neck, arms and legs. Unlike birds (think chicken), many dinosaurs had extensive feathers on their legs, so that's not unusual.

What is really different about Yi qi is that in addition to feathers, it has a thin sheet-like layer around the hands (bottom right). In other words, its wings have both feathers and a webbed membrane over them. This is the first time a dinosaur has been found with the elements of both a bat wing and a bird wing. Think about a bat with feathers, or a bird with membranous wings. Pretty bizarre huh? The membrane is not as well preserved as the bones and feathers and scientists had a hard time getting the exact shape of the membrane right. Therefore, the extent to which the membrane helps Yi qi to fly or glide is still a mystery.

While we associate feathers with birds and flight, many feathered dinosaurs may not have been able to fly. What were the feathers used for then? Scientists have shown that dinosaur feathers are coloured. Like present day birds, these feathers may be used for camouflage, or like the peacock, for sexual display.

Next time you think of a dinosaur, imagine a colourful feathered beast instead of a dry scaly monster. It'll change your perspective about Jurassic Park.