Back in 2010, Sinosauropteryx became the first dinosaur to be illustrated in its true colours. Since then, other feathered dinosaurs – including Archaeopteryx and Microraptor – have had their colours determined too.
This extraordinary detective story began with the discovery of fossilised melanosomes. These are the tiny packages of pigment inside feathers and hair in living birds and mammals, and are responsible for making your hair black, brown, blond or ginger. These melanosomes are incredibly tough, and under the right conditions can survive hundreds of millions of years in fossils.
When you look at the feathers of a living bird under a high-powered electron microscope, you can see melanosomes of different shapes. Zebra finches have round ‘phaeomelanosomes’ in the orange part of their feathers and sausage-shaped ‘eumelanosomes’ in the black parts. A team led by Mike Benton at the University of Bristol used this technique to look at the downy feathers along the head, neck and back of the fossilised Sinosauropteryx. They found that this carnivore was ginger with white stripes down its tail.