I am a nerd of many things…those at the top of the list would probably have to be comic books, poi, and dinosaurs. Since I was a little kid, dinosaurs have fascinated me and at one point I’d envisioned for myself a career in paleontology. There’s something unbelievably cool to me about trying to piece together the lives of extinct animals via a slow trickle of anecdotal evidence. When I look at a dinosaur skeleton–I actually see the animal living and breathing before me in the same way I imagine a car mechanic looking at an engine can see the car driving around in their heads.
One of my favorite mysteries surrounding dinosaurs is what color they were–we’ve had many dinosaur mummies preserved but all of them display only the texture of the dinosaur’s skin rather than the colors of it. This is part of the reason that dinosaurs are traditionally portrayed as being mottled and scaly, which is odd because their immediate descendents (birds) are found in a variety of colors.
We mammals invest lots of energy and body mass into facial musculature and as such most of our cues are visual. We can tell a lot about another mammal by how they orient their lips, eyebrows, and cheeks. Birds and reptiles seem very foreign to us because they have other ways of displaying their cues to their fellow birds and reptiles, but in the case of birds much of this is visual. We can make a pretty good guess as to dinosaurs’ visual acuity based upon the startling diversity we find in their skulls. Whether carnivore or herbivore, many dinosaur species are immediately identifiable by the ornamentation on their heads, which suggests that this orientation is at least in part how each species identified each other. Though the notion of Triceratops and T-rex having a battle to the death, the Triceratops goring the T-rex with its horns is a powerful image, the lack of any evidence of trauma to the horns of the Triceratops skulls we have found thus far suggest it’s more fantasy than reality. Our best guess is that those marvelous horns told other Triceratops who their brothers and sisters were in what was likely a very crowded world of massive horned dinosaurs.
So we know that dinosaurs probably had good vision–it was a primary mechanism by which they identified each other. So why the dull color scheme? I think a lot of it has to do with pulling cues from dinosaurs’ other extant relatives, crocodiles, and a lack of direct evidence to the contrary. At least until now…
For years now, some of the most interesting fossils in the world have come out of limestone beds in China. Limestone is an awesome preservative sediment because the grains in it are so fine they can preserve impressions of some of an animal’s soft tissue. It was from limestone beds in Germany that we first learned that Archaeopteryx (originally classified as a dinosaur) had feathers and was thus reclassified as a bird. The fossils coming out of China are even more exciting because they expand the roster of feathered dinosaurs to relatives of Velociraptor and Tyrannosaurus, offering tantalizing glimpses at a point in evolution where the line between dinosaur and bird was so blurry they were one and the same.
Then, two years ago, a study conducted on one of those fossils revealed that the level of detail in the limestone was so fine that scientists could make out structures they recognized within some of the fossilized feathers of these dinosaurs: melanosomes, which govern the color of feathers. We’ve known for quite some time which melanosomes are responsible for which colors in bird feathers all over the world–and now we can take that knowledge and explore the remains of these new fossils to answer a question that was considered unanswerable for most of my life: what color were dinosaurs, really?
The first fossil to be studied in this way was of a small theropod called Sinosauropteryx (the imaginative name translates roughly to Chinese lizard with wings…no I’m not joking. A side effect of being a dinosaur freak is that you wind up learning quite a bit of Greek and Latin along the way) that had a racing stripe-like cluster of feathers along its spine. A study of the melanosomes in these features revealed alternating bands of red and white and for the first time in history, we could say conclusively that we knew exactly what color an animal extinct for over 100 million years ways. It’s a stunning success of detective work and resourcefulness and it makes my little nerd heart soar 🙂
Now there’s another fossil that we’ve learned the melanosome structure for and it’s even cooler. I remember a couple years ago watching a NOVA special on Microraptor, another Chinese theropod that had been discovered with evidence of wing-like feature protrusions coming from both the arms and the legs, suggesting the road to flight as we know it had more than a few twists and turns. In that special, there were more than a few conjectural models made of the animal with earth-toned (and if I might say so, boring) feathers. Now, having studied the melanosomes in the preserved feathers from the Microraptor scientists have reached a different conclusion about its color scheme: it had black, iridescent feathers. And it is so freaking cool 🙂
I can’t wait to see more and more of these fossils studied and the diversity of color schemes among dinosaurs revealed. More than anything else, it’s just such a delight to see not how exotic some of these extinct animals were, but realize how much like the modern world the Mesozoic must have looked like. We may not have time travel, but for the moment I’ll totally take this.
The Polymath's Dilemma 