In a vivid episode of the PBS series It’s Okay To Be Smart, host Joe Hanson explained how certain animals like flamingos get their color from what they eat (carotenoids), before moving on to posit the question “Why Is Blue So Rare In Nature?”. After examining the wings of butterflies and feathers of birds, Hanson noted that it’s the structure of the wing and feather rather than pigment that causes them to appear blue.
Among living things, the color blue is oddly rare. Blue rocks, blue sky, blue water, sure. But blue animals? They are few and far between. And the ones that do make blue? They make it in some very strange and special ways compared to other colors. In this video, we’ll look at some very cool butterflies to help us learn how living things make blue, and why this beautiful hue is so rare in nature.