The colour Blue seems to be a rarity among land animals - mammals especially (we never see a blue cow or a blue dog and so on; only birds and fish display blue) - is there a reason for this?
Melanin is a pigment found in the iris (eye), hair and skin. Melanin protects DNA from damages caused by the sun, hence the darkening of skin. However, hair tends to get lighter in the sun despite containing melanin....does the pigment have a different role here?