> Blue is one of the rarest colors to appear in nature, which makes blue coloration in animals particularly fascinating.

Now hold on just a minute. The sky. The ocean. Glaciers. Even human eyes. Blue is so common "in nature" that the Earth, viewed from Mars, looks like a blue glass marble. https://www.universetoday.com/14446/photos-of-earth-from-mar...

Blue coloration in plants and animals is admittedly uncommon, but it's far from unusual. Animals tend to cluster around earth-toned colorways, and bright reds and greens are just as uncommon as blue.