birds than had showed up in more than 100 years. But were they genuine?
For a long time palaeontologists had talked about the possibility of feathered dinosaurs. This discussion stemmed from the theory that if any dinosaurs were warm-blooded, then the most likely would be small dinosaurs; and if they had any kind of insulation on their bodies, it would probably be feathers. By the late 1970s, many scientists had concluded that dinosaurs gave rise to birds. Though it was mostly speculation and there was scant evidence to prove it at the time, dinosaurs were being illustrated with feathers on their bodies in books everywhere.
Currie first saw a picture of the Chinese’s farmer’s find in a Beijing newspaper in 1996 after a trip to Mongolia. The article reported that a feathered dinosaur had been found, and the story was accompanied by a picture. ‘It was a little picture that didn’t look like anything,’ Currie recalls. ‘The idea of feathered dinosaurs had been with me for a long time, but still, what are your chances?’
Through a contact, Currie made arrangements to see the ‘feathered dinosaur’ specimen. He was slightly suspicious because he had been given an exact time for his viewing. When he arrived 10 minutes early, his contact walked him up and down the street so they wouldn’t be early. At the appointed time, the contact ushered Currie into a room full of reporters. ‘I realized that I had walked into a press conference and that they were going to show me this specimen in front of the Chinese press to see what my reactions were.’
Several different specimens were bought out one at a time. The boxes were then opened in front of Currie. ‘I would see a beautiful insect with spectacular preservation. Then they would bring out another box, and I would open it up and see a spectacular lizard fossil and so on.’
This dragged on for so long that Currie began thinking it was a diversion and that they weren’t even going to show him the feathered dinosaur. ‘I went to see it not because I thought it was feathered, but because I could see from the photograph that it was a complete specimen of a small dinosaur,’ he says. ‘Small dinosaurs are rare; carnivorous dinosaurs are rare. This was obviously a very, very important specimen’ – provided it actually existed.
Finally, the box with the feathered dinosaur arrived unannounced. ‘When they opened the lid of the box, my eyes probably expanded 20 times like a cartoon character,’ Currie remembers. ‘First of all, the specimen was beautifully preserved, but secondly, my eyes were drawn to these things that were around the outside of the body that were supposed to be feathers. In my mind, I had rationalized that it was probably dendrites or some kind of fungal growth. I just didn’t think the chances of finding a feathered dinosaur were all that good. Sure enough, within milliseconds, I knew that what I was looking at was real, and in fact, we did have the first feathered dinosaur.’
‘My eyes probably expanded 20 times like a cartoon character.’
Fossilized tarbosaur skin.
Dr Philip J Currie
Whether or not it was a legally collected, genuine specimen would take years to resolve. A week after Currie returned to Canada, he began fielding calls first from Japanese reporters and then from British reporters. Days later, on 19 October 1996, the story hit the front page of the New York Times under the headline ‘FEATHERY FOSSIL HINTS DINOSAUR– BIRD LINK‘. The story was accompanied by a drawing done by Michael Skrepnick, the artist who was travelling with Currie in China, and it reported Currie’s assessment that this was, in fact, a feathered dinosaur. ‘The whole world went a little crazy for a while,’ Currie says.
For years, dinosaur feathers continued to provide something of a mystery for scientists. Currie believes there is a possibility all the meat-eating dinosaurs known as coelurosaurs (‘hollow-tailed lizards’) had feathers as babies to provide insulation. The big species then shed those feathers as they grew into adulthood and no longer needed the feathers. The larger a dinosaur became the less its surface area was in relation to its mass or volume. Big animals have a problem ridding themselves of excess body heat. However, a small animal would lose heat really fast. So if small animals are warm-blooded, they have to be insulated in some way, such as with feathers or fur. However, a whale or an elephant is so large that it doesn’t need the insulation. Could it have been the same for Tarbosaurus?
‘It may well be that Tarbosaurus is free of feathers only because it’s big,’ Currie says. ‘When Tarbosaurus were born, they were probably only a half metre or 18 inches long. At that stage, they may have needed feathers. So there was a prediction, which is kind of cool, that if we ever find a small Tyrannosaurus then it should have feathers because it is closely related to these feathered dinosaurs.’
The cool part, Currie says, is that in 2004 a small Tyrannosaurus was found in north-eastern China that was about the size of a German shepherd and it had feathers. Currie explains that the big problem is that there are very few places in the world where conditions are such that feathers would be preserved, though skin impressions are often found in Mongolia and Alberta. Feathers rot away pretty quickly, so typically they decompose before they have a chance to fossilize.
The environment controls what is preserved. In most dinosaur-fossil sites there are no eggs or feathers found. However, in an environment like north-eastern China, where there was a lot of volcanic action, things preserve far better. Volcanic ash would rain down on the lakes. Sometimes the ash would kill a bird or a dinosaur running along the shore, and they would fall into the lake. Because the ash is very fine grained, mixed with the mud in the lake it preserves details very well. More importantly, it alters the chemical environment and kills the bacteria that would otherwise decompose the keratin – the horny material that forms fingernails, beaks and feathers – and leaves these structures preserved for science. ‘Suddenly, you have this amazing situation where you not only get fingernails and beaks but also feathers preserved,’ Currie says. That kind of preservation is critical for scientists to formulate theories about dinosaur feathers that connect them to birds.
Fossilized feathers have also provided scientists of the first evidence of dinosaur colours. Melanosomes, the biological structures that give feathers colour, were recently found to have been preserved in the small feathered theropod dinosaur seen by Currie in 1996 and subsequently named Sinosauropteryx, which lived 125 million years ago. The melanosomes allowed scientists to determine that the dinosaur had a red Mohican with a red and white striped tail. However, scientists have not been able to determine the colour for most other dinosaurs, even those whose skin has been preserved. Early artistic renderings of dinosaurs were in browns and greys and were based on the colour of the larger modern animals such as elephants and Komodo dragons, but scientists still have little to no evidence that dinosaurs were similar in colour to these.
‘We are absolutely nowhere with the colour of Tarbosaurus,’ Currie admits. ‘So far all we have is tarbosaur skin, but we don’t have any evidence of colour banding to show us that there might be melanosomes preserved. Of course, that doesn’t mean that they are not, because what might happen eventually is that somebody might take a look at the skin impression and find out that, yes, there are melanosomes there and we can actually figure out the colour on these guys.’
A close up of Komodo dragon skin – one of the largest reptiles alive on Earth at present – shows what dinosaur skin may have looked like.
Steve Gschmeissner/Science Photo Library
The fact that birds are the direct descendants of dinosaurs means that dinosaurs are not extinct. There are some 10,000 species still around. In fact, dinosaurs are actually divided into two groups, avian (those that fly, which we call birds) and non-avian (the land-dwellers that we normally think
