Before birds, there were feathers–naturally enough. Feathers, like hair, no doubt provided insulation and were grown by dinosaurs. Indeed, reptilian scutes when properly treated with a mild acid can fall apart into a feather-like structure. I suspect that the first advantage that they imparted was warmth for a small animal. But camouflage probably came second. When you have temporary structure like feathers, you can change color with the seasons. The color can vary by combining red and black pigments. It can pulse on and off as the feather grows or in different parts of the body to form pigmented bands. I have seen dinosaur-bird fossils where the bands in the feathers call to mind the wings and tail of a hawk.
But that’s just a hypothesis! Scientists have shaved a pigmented fossil into microscopic bits to identify the pigment granules and classify their color type: black or Irish-setter red. They applied their findings to the reconstructed fossil to see its color pattern. Behold!
The lovely illustration is by Chuang Zhao and Lida Xing
GrrlScientist has a fine, detailed description and lots of images of how the research on Sinosauropteryx was done with scanning electron microscopy.
It’s easy to create lines, cross-hatching, or speckles when two such color pulses combine into a moire pattern.