Why is blue such a rare color among Earth creatures?

Why is blue such a rare color among Earth creatures?
Until about 600 million years ago, seeing colors didn't matter so much to Earth's inhabitants — nobody had eyes.
Anyways...a lot have changed since then and pigments are like a color currency — many animals can take them from plants, digest them or modify them, and eventually display a version of the pigment in their outer layer. But they have to have evolved the right mechanisms to do so.

Many  of the colors in plants and animals come from pigments, colored chemicals that absorb certain wavelengths of light. Many pigments are useful in other ways — granules of melanin, for example, help keep bird feathers strong, and help protect human skin from the sun. Chlorophyll is a chemical that helps plants trap light for photosynthesis; it also makes them look green.

"While plants can produce blue pigments thanks to anthocyanins, most creatures in the animal kingdom are unable to make blue pigments. Any instances of blue coloration you come across in animals are typically the result of structural effects, such as iridescence and selective reflection.

Take, for example, the bluejay. This little bird produces melanin, meaning it should technically appear almost black. However, tiny air sacs in the bird's feathers scatter light, making it appear blue to our eyes. This is called Rayleigh scattering.

This is also the reason we see so many more blue butterflies and birds than reptiles, amphibians and animals with scales, skin or fur. It's much easier to achieve the appearance of blue through structural effects in scales and feathers. That doesn't mean it only appears in winged creatures. Some frogs and nudibranchs sport brilliant blue coloration as well."

Article//www.mnn.com/earth-matters/animals/blogs/why-blue-such-rare-color-among-animals#ixzz3kk0cyq7B

Photo credit: Michel Villeneuve53 via MNN
https://www.flickr.com/photos/villeneuve53/17105142839/in/pool-mothernaturenetwork/

#biodiversity   #pigment   #blue   #rayleighscattering