Modern Mythology: Scaly Dinosaurs
When I was growing up, my first dinosaur books had pictures like this:
Based on the scientific knowledge at that point, dinosaurs were lumbering scaly green-and-brown beasts, giant cold-blooded reptiles, with tails dragging on the ground and such a huge bulk that some of the biggest had to live in water. And, for what information the scientific community had in the early 1990’s, those pictures were a reasonable guess.
Today, however, those pictures are woefully out-of-date. Dinosaurs are no longer lumbering, dumb, and cold-blooded; instead, the consensus, as of 2009, was that most, if not all, dinosaurs were warm-blooded, and many were relatively intelligent as well, particularly the theropod dinosaur (carnivorous, bipedal dinosaurs like Allosaurus, Tyrannosaurus, and Velociraptor). But perhaps the biggest change to how dinosaurs look is in the skin.
First of all: not all dinosaurs were scaly. Some were, including Dakota, an Edmontosaurus found in 2007. This rare specimen was preserved with fossilized skin, showing a definitive scale pattern. In fact, in all of the “mummies” (fossils that preserve soft tissue and thus look similar to the mummies of Egypt) found of ornithopods (which include dinosaurs such as Stegosaurus and the hadrosaurs like Edmontosaurus) and sauropods (the long-neck dinosaurs), the skin has variations on this scale pattern.
The theropod dinosaurs, however, are a different story entirely. To my knowledge, there have been almost no theropod mummies found at this point, so it’s hard to compare the skin type. However, what we do find are feathered theropods. Not Archaeopteryx, which is still considered by many to be one of the first birds, although those specimens are spectacular in their own right. No, there are dinosaurs like Sinosauropteryx, Microraptor, and Velociraptor that have been found either with direct feather impressions or with “quill knobs”, which are essentially the bumps you see on the skin of a plucked chicken. The more feathered dinosaur fossils we find, the older the feather impressions we find. Some paleontologists are now suggesting that feathers were a basal characteristic to all theropods. In other words, everything from the first theropod Eodromaeus to Tyrannosaurus rex might have been covered in a downy, feathery fuzz!
Of course, all this talk of feathers is cool, but the real question is still: what color were the dinosaurs? Unfortunately, this is not an easy question to answer. In a few rare cases, though, we do have a pretty good idea. In the cases of Sinosauropteryx and Anchiornis, the fossil feathers were so well preserved that melanosomes, little pigment proteins, were preserved as well. For both dinosaurs, this revealed patterns of stripes, and ornate ornamentation like a bright red mohawk on Anchiornis‘s head.
For most dinosaurs, however, neither feathers nor skin are preserved, which leaves the job of determining what dinosaurs looks like up to paleoartists. The best of them draw on what information we do have on dinosaur skin and color, then compare to the closest living taxa to the dinosaurs: the birds and the crocodiles. From this data, they create views of dinosaurs that look less like this:
And much more like this: