How do we know what colour dinosaurs were?

For decades dinosaur colours were pure guesswork, until scientists found that some feathers and skin keep tiny pigment packets for over a hundred million years. Here is what we know, and what we still don't.

Pigment packets smaller than a cell

Feathers and skin contain tiny sacs of the pigment melanin, called melanosomes. Their shape hints at the colour: long, narrow melanosomes usually give black or grey, while short, round ones usually give reddish-brown.^[1]

Melanosomes last much longer than the rest of a feather. In exceptionally well-preserved fossils, scientists look at them with an electron microscope and compare their shapes with those in living birds' feathers to estimate the colour.^[1][2]

The first dinosaurs with known colours

Two studies came out close together in 2010. One looked at Sinosauropteryx from China and found alternating bands on its tail. The other looked at Anchiornis, a small feathered dinosaur, and reconstructed its whole colour pattern: a grey and black body, black-and-white patterned wings and a feathered crest on its head.^[3][4]

Later work found that Microraptor had glossy, iridescent black feathers like a crow's, and that Psittacosaurus had a dark back and a lighter belly.^[5][6]

Camouflage tells us about their world

Many dinosaurs with known colours were countershaded: darker on the back, lighter underneath. This pattern makes an animal harder to see in sunlight coming from above, and many living animals use it.^[3][6]

Borealopelta, an armoured dinosaur from Canada weighing over a tonne, was reddish-brown and darker on its back than its belly. Even a big, armoured animal still needed to hide from predators, which says a lot about how dangerous the predators of its time were.^[7]

What we still don't know

Melanosomes only tell us about blacks, greys and browns. Other colours come from other substances, like the yellows and bright reds of some birds, and these are rarely preserved. So most dinosaur pictures, including the ones on this site, still rely mostly on comparisons with living animals.^[2]