The Hidden Secrets Behind Dinosaur Color and Camouflage

 Abstract

Dinosaurs are often depicted in dull colors such as green or gray, much like the reptiles we see today such as pythons and iguanas. For decades, paleontologists could only speculate the colors of dinosaurs, as brighter colors created by pigments called "carotenoids", often weren't preserved in the fossilization process. Yet the discovery of melanosomes, tiny pigment-carrying structures, in fossilized feathers and skin has revolutionized dinosaur coloration as a whole.

Definitions

Pigments: Pigments are natural substances that produce color in the tissues of living organisms. They absorb certain wavelengths of light and reflect others, which gives them their distinct colors. In the context of dinosaurs, pigments such as melanin were responsible for the coloration of skin, feathers, and other tissues. Melanin, for example, can produce a range of colors from black and brown to yellow and red. In other situations, pigments can also be used for physiological processes and synthesis of certain substances.

Melanin pigment expressing different colors in canaries

Melanosomes: Melanosomes are specialized organelles found within cells that produce and store melanin, the pigment we discussed earlier. These microscopic structures are crucial for determining the color of an organism's skin, feathers hair and eyes. In paleontology, the discovery of fossilized melanosomes has allowed scientists to infer the colors and patterns of ancient creatures, specifically dinosaurs.

Picture of a melanocyte cell which contains melanosomes

Camouflage: Blending into Prehistoric Landscapes

Camouflage played a crucial role in the survival of many dinosaurs. Just like modern animals such as chameleons, dinosaurs used color patterns to blend into their environments and avoid predators and potential threats. One of the most fascinating examples of this trait is the small dinosaur, Psittacosaurus.

Psittacosaurus was a small, herbivorous Ceratopsian dinosaur, living from the Early Cretaceous period around 120 million years ago. Around 12 species of this dinosaur have been unearthed in Asia. They were strict bipeds during adulthood and had large skulls with a beak in place of their mouths. 

Based on proportion sizes of the skull, it is thought Psittacosaurus had extremely complex behaviors, being able to boast a brain so large. Scientists speculate that the genus must've had developed heightened senses and a higher level of consciousness. 

Fossil evidence from China, Mongolia, Russia and Thailand shows that Psittacosaurus had a countershaded color pattern. With a darker back and lighter belly, helping it blend into the forested environment it inhabited. Using the patterns of shadows, Psittacosaurus was able to counterbalance the varying brightness of certain areas, such as forests and use them to completely disguise itself. 

Image of Psittacosaurus from a multitude of angles

Although this small Ceratopsian used countershading for hiding away from predators, this technique is prevalent in both predator and prey. The modern-day grey reef shark and Cretaceous theropod Sinosauropteryx, were predators that used this ability to stay undetected.

Image of grey reef shark

Drawing of Sinosauropteryx

Mating Displays: Color in Courtship

Coloration in dinosaurs was not just about camouflage; it also played a role in mating displays and social interactions. Bright colors and elaborate patterns could have been used to attract mates or signal dominance, very similar to present-day paradise birds. The discovery of iridescent feathers in miniature theropod dinosaur Microraptor, suggests that these dinosaurs might have used their shimmering plumage to impress potential mates.

Microraptor was a small, four-winged dinosaur, yup four-winged, that lived during the Early Cretaceous period. Its feathers displayed and iridescent sheen, similar to that of a peacock. 

Similar to that of a crow, the Microraptor's' blue, purple and black feathers would change color, depending on how much light was being diffracted. However, the dinosaur's long tail and shiny feathers made it easier for predators to spot, proving the design was for finding a mate rather than protection from threats.

Image of multiple Microraptors with iridescent sheen

Predator Deterrence: Warning Colors and Patterns

Some dinosaurs might have used bright colors and patterns as a form of predator deterrence, as mentioned before. Just like modern poison dart frogs and insects, these warning colors could signal to predators that the dinosaur was dangerous or, a very toxic meal. 

The armored ankylosaur, Borealopelta is an example of a dinosaur that might have used suck warning colors. Fossil evidence suggests that this tank had reddish tones, often signaling in biology, that a species is to not be messed with.

Reddish-brown tones seen in reconstruction of Borealopelta

Along with that, this absolute truck of a species was a staggering 18 feet long, clocking in at almost 1.5 metric tons. If that wasn't enough to deter any threats, besides being fully armored, Borealopelta had two protruding spikes on the side of its torso each 50 centimeters in length.

Conclusion: A Vivid Picture of the Past

By comparing the coloration of dinosaurs with those of modern animals, scientists can draw fascinating parallels and differences. For instance, the discover of melanosomes and a variety of pigments in dinosaur feathers has shown that many dinosaurs had color patterns similar to those of modern birds. Completely transforming our perception of these ancient creatures, no longer do we imagine dinosaurs as dull, grey beasts.

Image comparing a small raptor to a modern-day chicken along with another bird