Question: How do you know what colour dinosaurs were?

Maria McNamara answered on 12 Nov 2019:

We can currently infer what colours only feathered dinosaurs were by looking for traces of melanin pigment in their feathers. In vertebrates, melanin occurs as microscopic little features called melanosomes that are shaped like balls or sausages. The sausage-shaped forms are linked to black and dark brown colours, whereas the ball-shaped forms are linked to reddish / ginger colours. The shape of the melanin granules in fossil feathers – including those on dinosaurs – tells us whether they were ginger, black or white (if there are no melanosomes). However in modern birds melanin usually occurs with other pigments that can modify the colour – in other words, if you find rod-shaped melanosomes in fossil feathers it doesn’t necessariliy mean that they were black. They could have been yellow, red, blue, etc. But we have a lot more work to do before we get to that point.