Blue animals are rare.

Scientists have described that there are no blue tigers. No blue bats, no blue squirrels, or no blue dogs. Even blue whales aren’t that blue. Animals come in pretty much every color, but blue seems to be the rarest. What’s cool, though, is that when we do find a blue animal, they’re awesome looking. Nature doesn’t do halfway with blue. To understand why this is, we’re going to journey through evolution, chemistry, and some very cool physics. But, first, we’re going to need to understand why animals are any color at all, and to do that, we need to go look at some butterflies. because butterflies are awesome. And if you don’t think so, you’re wrong. This is Bob Robbins. He’s curator of Lepidoptera at the National Museum of Natural History in Washington, D.C. Butterflies are awesome. Make no mistake about it. They’re a group of moths that evolved to be active during the day, and if you’re active during the day, you have an advantage: You can use light to communicate. You probably realize this, but out of all insects, butterflies display the brightest and most detailed patterns. And there’s a good reason for that: The colors in butterfly wings deliver messages like “I’m toxic”, or “I’m a male, and this is my territory”, but not all butterfly colors are created equal. If we zoom in on a butterfly wing, we see the colors come from tiny scales. It’s actually how moths and butterflies get their scientific names. There are a few animals that have blue coloring, such as the blue morpho butterfly, the blue poison dart frog, and some species of birds, such as the blue jay and the blue peacock. However, it is relatively uncommon for animals to have a true blue color. This is because blue pigments are not as common in nature as other colors, such as brown, green, and red. Additionally, many animals that appear blue, such as the blue whale, actually have a different coloration that appears blue. Absolutely, butterflies are indeed fascinating creatures, and their colors are a result of intricate evolutionary processes, chemistry, and physics. The vibrant colors in butterfly wings are indeed produced by tiny scales, each of which is covered in even tinier structures. These microscopic structures manipulate light, creating the vivid hues that we see.

The phenomenon behind the colors of butterflies and many other animals is called structural coloration. Unlike pigments, which absorb certain wavelengths of light and reflect others to create color, structural coloration involves the interaction of light with intricate nanostructures. These structures cause light waves to interfere with each other, amplifying specific wavelengths and creating vibrant colors. Now, as for the rarity of blue in the animal kingdom, it's true that blue is relatively uncommon. This is because creating blue pigments or achieving blue structural coloration is a complex process evolutionarily. In nature, there are very few substances that can absorb non-blue light and reflect blue light. One example is melanin, which can appear blue under certain conditions, but it's not a true pigment in the way that red, yellow, and other colors are. Some blue animals, like bluebirds and blue jays, achieve their color through the microscopic structure of their feathers. Morpho butterflies, found in Central and South America, are another example of butterflies that display stunning blue hues due to structural coloration. The rarity of blue in animals makes blue species even more awe-inspiring when we do encounter them in the wild. Nature's ability to create such vivid and diverse colors through evolutionary processes and intricate physics is truly remarkable. Blue animals are indeed rare in the animal kingdom, and when they are found, they are often considered remarkable due to the scarcity of this color in nature.