There are blue animals, but the species are small in number compared to the other colors among living things, such as red, orange, yellow, and brown. Sure, when we look up to the sky, we see blue. When we look at the Earth from space, we see a blue marble. But the few animal species that look blue don't use pigments -they use physics. And those physics are complicated. It turns out that animals are better at engineering than they are at chemistry.
Okay, there's one exception to the pigment thing, which we learn about in the video. Our friends at It's Okay To Be Smart explain why it's so hard for nature to create the color blue. -via Boing Boing