What Colors Were the Dinosaurs?

When I was a wee lad who was very into dinosaurs, I always was troubled by a question about my favorite group of animals: What colors were the dinosaurs?  See, we could look at teeth and stomach contents to see what they ate, we could look at the leg structure and footprints to see how they moved, and we could even look at the internal bone structure to see how they grew.  But despite knowing so much about these animals, we still had no idea what they looked like.  I could look at artists’ renditions of dinosaurs, but all of the colors used were either imagined by the artist or pulled off of some living animal and it was completely possible that the whole color scheme was wrong.

Luckily for those interested in the most majestic of beasts, the past few years have been incredibly eye-opening to the paleontological community.  If you look into dinosaurs for the first time in years, realize your childhood and Jurassic Park are ruined, go into a period of denial, and then come out of your shock amazed at the glory that is dinosaurs, don’t worry, you’re not alone.  Some things you may have missed include:

Spinosaurus was a four-legged animal with a lifestyle similar to a crocodile.

Triceratops may have had quills on its back.

-Dinosaurs were warm-blooded, having the same metabolic abilities as modern mammals.

But the one that gets a lot of people is that nowadays tons of dinosaurs are being depicted with feathers.  People get mad and say, “How can I be scared of Velociraptor if it’s all fluffy?  How can Tyrannosaurus rex chomp lawyers if it’s just a big bird-thing?”  To those people, first of all, I’d like to point out that with or without feathers, these animals are just as effective at killing you.  (My buddy Ethan thinks that Velociraptor was actually scarier with wings, because of a theory that like many modern birds of prey, raptors may have flapped to help keep balanced on top of larger prey while they slashed at them with their enlarged toe claws.  Yikes.)  Then I’d like to point out how we have actual feather imprints in rocks, so it’s not like scientists are just going out and drawing fluffy dinosaurs to make people mad.  And finally, I’d like to point out that feathers add a whole new layer of interest and complexity to these great ancient beasts.  And, Answers in Genesis, stop saying that those clearly imprinted feathers with vanes and rachis are just collagen fibers that somehow happen to form the shapes of wings and tail feathers on many dinosaurs.

The study of feathered dinosaurs has revealed many interesting secrets, but the one most appealing to my child-like dinosaur interest is the existence of trace pigments among the feather imprints in four different dinosaurs, giving us a glimpse into the world in which dinosaurs lived and their manner of surviving within it.  I will go through these four dinosaurs and their colors, but I want to point out something important to note.  All of these dinosaurs, being feathered, were closely related to those that would become the ancestors to modern birds.  Some might argue that some of these dinosaurs, particularly one, are birds.  Really, the separation between dinosaurs and birds is iffy and the change between them is gradual, with not all the features changing in a particular instant, so scientists have trouble deciding where to draw the line.  Part of this challenge stems from the fact that they have traditionally all used Linnaean classification (kingdom, phylum, class, etc…) but evolutionary biologists are starting to prefer a cladistic system of classification in which organisms are classified by clades, the sets of all organisms descended from a particular common ancestor.  In the Linnaean system, the division between birds and dinosaurs is based on what features you use to define the two groups.  In the cladistic system, birds’ descent from dinosaurs means that they are still dinosaurs.  I will not consistently use one system or the other, because I think they both emphasize different points of importance.

The Bird-Dino with the Red Crest

The feathered dinosaur Anchiornis, illustrated by Ethan Schmunk.

Anchiornus huxleyi

Of the dinosaurs for which we have evidence of specific colors, the one we know best was unearthed in 2009 in the Liaoning Province of China.  Dating back to the Jurassic Period about 160 million years ago was the fossil of Anchiornis huxleyi.  Anchiornis was a small little sucker, measuring just over a foot in length.  It sported a long tail, switchblade claws like Velociraptor, and feathered wings.  The name Anchiornis means “almost bird” because in life the creature would have looked like a little flightless bird, but the creature was actually a smaller relative of Troodon, which you may or may not know about depending on how nerdy you are, but be assured that troodontids were pretty cool dinosaurs considering Troodon‘s awesome brain-to-body ratio which is the highest among dinosaurs.

Close examination into the contents of the feather imprints showed traces of melanosomes, pigments that also exist in modern bird feathers.  The shape of each melanosome determines the color it will make the feathers.  By looking at these shapes, scientists were able to determine nearly the full color of the animal (though there are uncertainties about the tail).  Anchiornis was primarily black and grey with white stripey patterns on its wings.  The striking piece of color on the almost bird was the crest of red feathers on the animal’s head.

If you know anything about birds, you know that colorful features are very often to attract mates. Though there’s not really a way to know for sure, I think that this is the most obvious potential use of the crest for Anchiornis. In most animals alive today, it is the males that do the attracting with their flashy features, crazy dance moves, or violent attacks on each other. Perhaps Anchiornis rocked out with crazy head bobs or something else sexy. If Anchiornis‘s crest was for attracting females, then might the females not even have had it?

Variations in physical characteristics between the sexes of a species is known as sexual dimorphism. For an example of this, think of a chicken. The rooster is more colorful and has a larger comb and wattle, while the hen is really plain-looking (I hope I’m not offending any chicken feminists out there). Sexual dimorphism is incredibly hard to determine in dinosaurs. Having only the bones, it is difficult to know if two different but similar specimens are two related species or simply the male and female varieties of the same species. Usually, paleontologists assume the more likely and guess that they are distinct species. But it is still entirely possible, especially when dealing with color and feathers, that the two sexes could have had wholly different phenotypes.

Another interesting question arises from the idea that Anchiornis may have used its bright crest for courtship.  Crests are a very frequent feature among dinosaurs.  From the trumpeting Parasaurolophus to the Dilophosaurus that Jurassic Park decided to give a spitting ability, many dinosaurs had elegant headgear and perhaps they had bright colors on them too.  Of course, this is only speculation, as is the idea that Anchiornis or any dinosaur used bright colors to attract mates.

Painting a Missing Link

Archaeopteryx by Ethan

Archaeopteryx lithographica

When most people think of dinosaur to bird evolution, their first thought is of Archaeopteryx lithographica, the so-called “first bird.”  Unearthed in Solnhofen, Germany in 1861, Archaeopteryx (“ancient wing”) was a curious and unfamiliar animal for the time.  It had the body shape, skeletal structure, long tail, teeth, and claws of a theropod dinosaur, but the wings and feathers of a bird.  Having been discovered just recently after Charles Darwin’s publication of On the Origin of Species, many evolutionists (not a huge portion of the general public; remember that Darwin’s ideas were initially very unpopular as they still are today in many places) saw this as proof of evolution by its connection between two diverse groups.  The mystery of where birds fit on the great tree of life was solved.

But Archaeopteryx‘s role in this whole thing has been heatedly debated.  Was it a bird or a dinosaur?  When it was first discovered, Archaeopteryx was called the “first bird” and the name stuck.  If you open up your high school biology textbook to the evolution section, you’ll probably see Archaeopteryx still labeled “first bird” and also called a missing link.  Nowadays, however, with more of the evolutionary chain known and filled, paleontologists don’t view this little dinosaur the same way.  It was not a singular jumping point but simply part of a spectrum with scaly dinosaurs at one end and modern birds at the other.  Archaeopteryx lived in the late Jurassic Period 150 million years ago, meaning that feathers had been around for a while, but full-fledged birds were still a ways off.  So the idea that Archaeopteryx is the single most important link does not really respect its place in the evolutionary ladder.

Archaeopteryx is classified today as a maniraptoran dinosaur, part of the same group that includes Velociraptor.  Although the ancient wing was originally assumed to fly, scientists have come to realize that its wings were not developed enough to generate powered lift, though the animal may have been able to glide short distances.  Archaeopteryx lived at a time when sea levels were much higher and consequently Europe was flooded in many areas, creating various islands with large lengths of seashore that the feathered dinosaur could pick for food.  It is possible that the “first bird” was a beachcomber.

I’ve spent enough time talking about the basics of this super interesting dino-bird, so I’ll get to the color already.  In 2012, scientists analyzed part of the imprinted wing feather of an Archaeopteryx.  They found that it was full of traces of a copper pigment which in modern birds produces a dark color.  A newer study in 2013 looked at the entire feather and realized that it was actually light in color, but was only dark on the end and around the edges.  The reason for this is not something that I would have thought of off the top of my head.  Apparently, in modern birds, copper pigment acts as an antibacterial and helps keep mischievous bacteria from fraying the edges of the feathers.

Unfortunately, it is not possible with our current knowledge to determine the color patterns across Archaeopteryx‘s whole body, because color data comes from the single feather, however, I think you might be able to score some points with your Archaeopteryx-obsessed biology teacher by being able to tell him or her something about the animal’s feather pattern and its antibacterial properties.

Tiger Stripes

Sinosauropteryx prima

Sinosauropteryx prima

Of all the dinosaurs I am going to talk about, Sinosauropteryx is the least bird-like.  The little creature measured about four feet long and lived in China about 130 million years ago on the edge between the Jurassic and Cretaceous periods.  The name Sinosauropteryx means “Chinese lizard bird” and the combination of its two nominal animals shows some of the great surprise scientists had in discovering it.  The Chinese lizard bird is significant in paleontological history because it was the first non-“bird” dinosaur discovered with feather imprints surrounding its bones.

Sinosauropteryx‘s feathers excited the scientific world when they were first observed in 1996, but interest in the Chinese lizard bird resurfaced in 2010 when the fossil was reexamined for traces of melanosomes.  The melanosomes in Sinosauropteryx were reddish and based on their concentration, scientists inferred that the animal’s base color was an orangish hue.  However, the part that interested scientists most was the tail of the three-foot long dinosaur, which had bands of melanosomes with empty areas in between.  This suggested stripes.

We humans tend to be suckers for animal patterns, if you’ve ever noticed.  We have leopard print everything and occasionally a zebra or giraffe skin pattern will show up on someone’s phone case or something.  So perhaps if a stripey dinosaur like Sinosauropteryx showed up today, we’d be all over it.  I would totally get Sinosauropteryx-print merchandise out the wazoo.  But when we look at the colorations on leopards, zebras, and giraffes, we have to realize that these all serve practical purposes for the animals.  So what did Sinosauropteryx use its stripes for?

There are a lot of theoretical purposes, but the main two are probably pretty obvious: camouflage and sex.  We’ll start with talking about sex.  It’s always the topic anyway.  After all, in nature, one of the biggest factors affecting your species’s survival is how fast and often you can get sex.  So if you’re a male dino-bird, you’ve got to attract the womenfolk and a good way to do that might be with a sexy stripey tail.  Perhaps we can imagine male Sinosauropteryx doing some sort of wacky dance around its potential girlfriend, waving its tail in the air, saying “Look at me!  Look at me!” before getting totally friend-zoned as the girl wanders off after some other dude with a snazzier tail.

Or perhaps Sinosauropteryx‘s stripes were not for showing off, but rather for hiding away.  Tigers today use their stripes to camouflage among vegetation as they stalk unwary prey.  The light-and-dark pattern on their skin mimics the light-and-shadow of plants, meaning that the tigers blend into their surroundings.  Maybe Sinosauropteryx used its stripes to hide from predators.  After all, the Chinese lizard bird wasn’t all that big in a world where some of the carnivores weighed five tons or so.  Whatever its stripes were used for, Sinosauropteryx gives us an interesting look at a dinosaur’s pattern.

X-Wing Fighter of the Cretaceous

Microraptor zhaoianus

Microraptor zhaoianus

Of all the winged dinosaurs, one of the most spectacular has to be Microraptor, the “little thief,” which lived in China during the Early Cretaceous Period, 130 million years ago.  Measuring only two feet long, Microraptor was built to live in trees.  And, yes, it was a true raptor, or as scientists put it, a dromaeosaur.  But what makes the little thief stand out among dinosaurs is the level of development in its wings.  A lot of feathered dinosaurs may have been able to glide short distances, but rarely did they have fully developed flight feathers like modern birds.  Microraptor, however, outdid modern birds by having not just two, but four wings with fully developed flight feathers.

The little thief did not have the muscle power for powered flight, so it did just glide, but its brilliantly crafted body allowed it greater control than most gliding animals.  Microraptor could have held its forewings up to support itself in the air while its back wings would have been held downish for use as rudders, making it sort of like an X-Wing Fighter from Star Wars, I suppose.  Or at least that’s how I explain the animal to little kids.  This would have given the animal expert steering and possibly to some extent even a swooping ability.  Fish bones found inside the gut area of a fossilized Microraptor along with forward-angled teeth indicated that the animal was at least partly piscivorous.  Perhaps it swooped over lakes and snatched fish from the water.

Microraptor tended to be portrayed by paleoartists in weird shades of brown, blue, and green for some reason or other.  Its unique four-wingedness made it popular among dinosaur fans.  But in 2012, the little bird-dino was found to be a lot prettier than the raggedy crude-looking feathered nightmares spawned by the paleoartists.  Analysis of melanosomes in a well-preserved Microraptor specimen revealed that the structure of pigments in the little thief was similar to that of birds with black glossy feathers.  That’s right: Microraptor was a bit shiny.

The use for these feathers is a huge topic of debate.  The animal was a glider, of course, but the gloss must have had another purpose.  Of course the topic of attracting mates shows up.  Maybe male Microraptor made a flashy show for the chicks.  But some scientists have pointed out that the gloss might be an accidental side-effect of feathers designed for another purpose.  After all, some animals like moles have glossy coats even though they rarely have light shining on them at all.  One idea is that the chemical nature of the feathers resisted moisture soaking in.  Of course, this is highly speculative and there remains a lot of mystery with very few easy answers.  What do you think?

Summing It Up

Other than birds, these are the only four dinosaurs whose colors are at least partly known to science.  The explosion of interest in dinosaurs could lead to more discoveries in the near future.  But the biggest problem we’re left with is that all of the traces of melanosomes we find come from feathers, which means we can only be certain of colorations, for the moment at least, of a very small group of related feathered dinosaurs.  We still don’t know about the long-necked sauropods, the horned ceratopsians, the armored thyreaphorans, or any other large dinosaurs.  The world of dinosaur color still remains largely to our imagination, but every glimpse is still fascinating and here’s to hoping that in the future we will find new ways to look for evidence and achieve greater knowledge of a lost world.

Special thanks to Ethan Schmunk who illustrated these wonderfully accurate pixel-art depictions of feathered dinosaurs.  Ethan’s a boss at drawing dinosaurs and he’s always up-to-date on his dino facts.

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