“Dinosaurs are very much still alive, and are more successful and numerous in terms of species numbers now than they have been at any other point in their roughly-230-million-year history.”—John Pickrell
The following is our interview with John Pickrell, author of Flying Dinosaurs: How Fearsome Reptiles Became Birds:
Question: Are dinosaurs still among us?
John Pickrell: Dinosaurs are very much still alive, and are more successful and numerous in terms of species numbers now than they have been at any other point in their roughly-230-million-year history. This is because birds are dinosaurs; they evolved from within the speedy, bipedal group of predators called theropods, which includes such creatures as Velociraptor and T. rex. Birds are not only the descendants of the dinosaurs—they actually are living dinosaurs. They are simply a small, specialized flying form of theropod. Right now there are nearly ten thousand known living species, and perhaps as many as four hundred billion individuals flitting about on the planet.
Q: What did dinosaurs use feathers for?
JP: Since the first dinosaur fossil with feathers was discovered in China in 1996, around 40 species have been found with feather impressions or direct evidence of feathers of some kind. This has shown us that feathers existed in dinosaurs long before they had any purpose in flight. Feathers are so entwined in our minds with flight, this seems counter-intuitive, but flight feathers are highly specialized structures and can’t have appeared fully formed. We now know feathers had an entirely different purpose initially. The earliest feathers we see on dinosaur fossils are simple, fluffy filaments, like the down of a chick, and they were used for insulation. Only later were feathers co-opted for display purposes and eventually for flight.
Q: What are the new fossil discoveries telling us about dinosaurs that we did not know before?
JP: Beyond confirming the dinosaur–bird link, the fossils have offered clues about how feathers evolved in the first place, and how they might have been used. What is most exciting about the latest discoveries, though, are hints at how dinosaurs did eventually take to the skies. We now know that the dinosaurs most closely related to birds were small predatory species which had four wings and a long feathery tail. Their hind limbs and tails had flight feathers of the kind we see only on the forelimbs of modern birds, so it’s likely they used them to glide between the trees of China’s swampy Cretaceous forests. We also now know that dinosaurs were bird-like in many other aspects of their physiology and behavior too. From nesting, brooding and sex, to metabolism, development and even the diseases that afflicted them, many of the traits found in birds today were inherited from the dinosaurs. The boundary between dinosaurs and birds has become utterly blurred.
Q: What has led paleontologists to think that birds might have descended from dinosaurs?
JP: The first clue of the link between dinosaurs and birds was the discovery of a fossil of the species Archaeopteryx in Germany in the 1860s. Archaeopteryx had the long bony tail, teeth and claws of a reptile, but it was clearly a bird, with large wings and fully developed flight feathers. It is still regarded as the “first bird”. Some remarked upon the similarity with small dinosaurs at the time, but the idea that birds were descended from dinosaurs was largely obscured again until the 1960s and 70s when the “dinosaur renaissance” saw leading experts re-imagine carnivorous dinosaurs as speedy, quick-witted animals with high metabolisms that were much more similar to birds than reptiles. The final clincher was the discovery of the first feathered dinosaur, Sinosauropteryx, in China in 1996. Experts had thought dinosaurs were feathered but never expected to find feather impressions on a dinosaur fossil. The discovery shook the foundations of paleontology.
Q: One doesn’t think of T. rex males as nurturers but were they good dads?
JP: We don’t know for sure, but it seems entirely possible. The males of many living birds are actively involved in brooding nests and rearing chicks, and this may have been the case for carnivorous dinosaurs such as Tyrannosaurus too. There are some fossils of related, smaller species of dinosaur, which hint that the animals preserved in the act of brooding their nests were male. Only more research will tell.
Q: Why did dinosaurs eventually take to the skies?
JP: Flight opens up a whole load of new possibilities for terrestrial animals. It means you can travel very efficiently over large distances. It makes it easier for you to swoop in on prey and rapidly escape from land-bound predators. These may have been some of the drivers that pushed the evolution of dinosaurs in that direction. In terms of how they did it, experts are still undecided whether they were running animals that used feathers and wings to give them a bit of extra lift, or if they were gliding animals that came from the trees down.
Q: What are learning about the way dinosaurs sounded and looked like?
JP: Along with the new fossils, and renewed interest in dinosaurs, have come fresh interpretations of how dinosaurs lived their lives. In 1993 nobody could ever have predicted that we might know something about the sounds that dinosaurs made and the colors they were decked out in, but clever new methods have begun to probe these kinds of details too. For example, a series of studies since 2010 have looked at the fine structural features of feathers, still preserved in some of these fossils, to find tiny structures that correlate to feather color in modern birds. Using this method, plumage colors have now been estimated for around five species of dinosaur showing they had features such as ginger and white tail stripes or black iridescent wings.
Q: You have a fascinating chapter on the black market. How are fake fossils impeding paleontologists?
JP: Both fake fossils (which are built from scratch or made as composites from the fragmentary remains of real fossils) and black market specimens, are having a negative impact on Chinese paleontology. Fake fossils are now are so widespread in China that most regional museums will have at least a few on display. Experienced experts in the field are able to discern them, but they are produced with such skill that it takes a fine eye to spot them. Black market fossils, dug up without any information about the exact location and geological layers that they came from, lose much of their scientific value as it’s not then possible to pinpoint their age or find other clues from the sediments around them.