Eumelanin is a black-brown pigment and pheomelanin is a red-yellow pigment. The amount of the different pigments determines hair color. Black and brown hair has mostly eumelanin, red hair has the ...

But all it would take is a slight change in a pigment called pheomelanin for these popular cats to appear yellow or red instead. Pheomelanin pigment is present in all ginger cats, but the level of ...