Moreover, due to the scarcity of blue pigments or dyes in plants and animals (except indigo, which is found in many plants and also in some animals, e.g. in some snails), the vivid blue details that can be seen on many birds, insects or lizards, and also on the genitals or faces of a few monkeys, are not caused by pigments or dyes, but by optical interference or diffusion in thin transparent layers.
Many fruits and flowers contain blue organic compounds (anthocyanins), but those are useless for making dyes or pigments, because they are unstable and they loose their color very quickly.
Many fruits and flowers contain blue organic compounds (anthocyanins), but those are useless for making dyes or pigments, because they are unstable and they loose their color very quickly.