Nature gives us a vast array of colors in animals, but blue is remarkably rare. Have you ever wondered why? The answer lies in several biological and physical factors. And that’s why the list of blue animals is so short.
Limited natural pigments
Most animals get their colors from biological pigments, but blue pigments are extremely rare. This is because the chemistry to create blue pigments is complex and rare in nature. Pigments that produce brown, red, and yellow colors, such as carotenoids and melanins, are easier to produce biologically.
Blue animals use physics to create that appearance. In mammals, the color blue is rarer. Some whales and dolphins have blue skin, and some primates, such as golden snub-nosed monkeys, have blue faces. Meanwhile, mandrills display blue on their face and backside. However, the fur of land mammals does not appear bright blue under visible light. A curious case is the platypus, whose fur glows in shades of blue and green under ultraviolet light. Birds also have an additional light receptor that allows them to harness ultraviolet light. Feathers that appear blue to humans reflect even more ultraviolet light.
This explains why blue is so rare in nature and why the word “blue” appeared late in the world’s languages, after terms such as black, white, red and yellow.
Physical structures that deceive the eyes
Many animals that appear blue actually have no blue pigments. Their blue color comes from microscopic structures in their skin, feathers, or scales. These structures manipulate light in such a way that only the blue color is reflected.
An animal’s color often serves an evolutionary purpose, such as camouflage. Brown, green, and gray shades offer better camouflage advantages in many environments. Because of this, these colors are more common than blue. Blue animals might stand out too much, making them more visible to predators.
Although blue is rare, some animals display it spectacularly.
- Morpho butterfly.
- Blue poison dart frog.
- Blue surgeonfish.
- Bluebird, bird of Colombia.
- Blue lobster.
- Electric blue tarantula.
- Blue-eyed grasshopper.
- Blue bee.
- Ringed octopus.
- Lizard Tizon.
Plants don’t “choose” blue either
Fewer than one in ten plant species are blue, and blueberries are not technically blue. Plants achieve this color by mixing natural pigments. Anthocyanins, red pigments, are the most common, and their appearance changes with acidity. Combined with reflected light, they produce colorful flowers such as hydrangeas and bluebells. Only a few tropical understory plants have blue leaves.
The main reason is the physics of light. Pigments reflect light of the color they appear to be. Green chlorophyll, the most common plant pigment, reflects green light, giving plants their characteristic color. Blue light has more energy in the visible spectrum. Blue leaves reflect this high-energy light and use lower quality light, which limits their growth.
The rarity of blue animals and blue plants is a fact. Although they are strange, they both remind us of the incredible diversity and complexity of life on our planet.
