Does albinism cause lack of ALL pigment, or just black pigment? Does this very on the species?
Mammals and birds only have melanocytes (these produce varying amounts of brown or black pigment), so that's the only pigment that needs to be affected for them to display albinism. But other types of animals have multiple types of chromatophores. An albino snake, for example, would also need to have the cells that produce reds, yellows, and blues deactivated to appear white/colorless. For these animals to appear as albinos, all pigments would have to be affected.
