When people say, “that’s not a color found in nature!” they often mean neon green or hot pink. But you know what’s really rare in nature? Blue! Even though the sky and water look blue, they aren’t actually blue. Some birds, plants, and butterflies show off blue colors, but it’s super rare because it’s hard for nature to make. This is interesting since many people say blue is their favorite color.
About 600 million years ago, eyes began to evolve. Before that, living things could sense the sun’s energy but couldn’t see it. Then, a predator evolved to see better, which helped it catch prey. This was a big deal in evolution because suddenly, color became important for survival. Animals started using colors to show danger, hide from predators, or attract mates.
Animals use different ways to get their colors. Yellows, oranges, and reds come from carotenoids in their diet. For example, cardinals get their red color from eating insects and berries, while flamingos turn pink from eating algae and tiny animals. But if you fed flamingos blueberries, they wouldn’t turn blue. Blue is tricky because it can’t be absorbed like other colors. Instead, animals have evolved special structures to reflect light in a way that makes them look blue.
Scientists at the Argonne National Laboratory studied hundreds of birds and found that their feathers contain keratin, the same stuff that makes up our hair and nails. As feathers grow, keratin separates from water inside the cells. When the feather matures, the water evaporates, leaving a keratin structure that reflects light to show blue. This is called structural color, different from pigmented color. Our skin can make browns, reds, and yellows with pigments, but not blues or greens.
Snakes and frogs aren’t actually green. They want to blend in with trees or lily pads, so they evolved to look green. They can’t make blue or green pigments, so they have yellow pigments in their skin and a blue structural color. When a smooth green snake dies, the yellow fades, leaving only the blue structures. So, even though blue is rare in nature, it can exist, but it’s tough to make.
Some fungi, insects, plants, and crustaceans have evolved blue pigmentation, but not vertebrates like us. We don’t know exactly why, but at least we can mimic it with things like blue hair dye. Have you ever tried coloring your hair blue? It’s a fun way to experiment with this rare color!
Want to learn more about colors? Check out some cool videos on the topic!
Explore the concept of color by creating your own color wheel. Use paints or colored pencils to mix primary colors and discover how secondary and tertiary colors are formed. Pay special attention to the placement of blue and discuss why it is unique in nature.
Go on a scavenger hunt around your home or school to find objects that are naturally blue. Make a list of these items and research how each one gets its blue color. Share your findings with the class and discuss the rarity of blue in nature.
Conduct an experiment to understand structural color. Use a prism or a CD to split white light into its component colors. Observe how light reflects and refracts, and relate this to how animals like birds display blue colors through structural coloration.
Imagine you are an animal that needs to blend into its environment. Design a creature using art supplies, focusing on how it would use color for camouflage. Explain your color choices and how they help your creature survive in its habitat.
Choose a blue animal, plant, or object found in nature and research how it gets its color. Create a presentation or poster to share with the class, highlighting the science behind its blue appearance and any interesting facts you discover.
When people say, “that’s not a color found in nature!” they’re usually referring to neon green or hot pink. But you know what they should be talking about? Blue! Blue is a tough color. Yes, the sky appears blue and water appears blue (even though they’re actually not). While some birds, plants, and butterflies display the color blue, it’s actually a super rare color in nature because it’s really difficult for nature to create, especially since many people name blue as their favorite color.
The eye evolved 600 million years ago. Before that, organisms on Earth sensed the sun’s energy without seeing it. Eventually, a predator likely evolved a better way to perceive that energy and catch prey! This was a significant change in evolution; suddenly, color became incredibly important for survival. This new predator initiated a multi-million-year race to evolve colors to indicate danger, camouflage, or for sex differentiation to hide breeding females.
Color in the animal kingdom comes from various evolutionary tools. Yellows, oranges, and reds come from carotenoids in our diet. For example, cardinals’ red comes from insects and berries, while flamingos absorb carotenoids from algae and tiny animals to become pink (without it, they’re just white). When we eat red, yellow, and orange foods, animals can use those pigments to create color, but if you fed flamingos blueberries, it wouldn’t turn them blue… blue isn’t as easy to absorb. Instead of using pigments, animals evolved physical structures to reflect light in just the right way.
By analyzing hundreds of birds, scientists at the Argonne National Laboratory found keratin inside the cells of feathers. Keratin is the same substance that makes up hooves, hair, horns, and fingernails. As the cell grows, the keratin molecules inside the cells separate from the water, and once the feather matures and the cells die, the water evaporates, leaving this keratin structure, which refracts light at just the right angles to cancel out yellow and red wavelengths, reflecting only blue! This is called structural color, as opposed to pigmented color. Our skin can use pigmentation to create combinations of browns, reds, and yellows, but not blues… or greens, actually.
For example, snakes and frogs aren’t actually green, but they want to hide by sitting in trees or on lily pads, so they needed to evolve green! Since they can’t produce blue pigment and green pigment, they evolved yellow pigment in their skin, along with a blue structural color. When smooth green snakes die, the yellow pigment fades, leaving just the structures that create blue. So, even though blue isn’t a common color in nature, it can exist; it’s just tough. Somehow, thanks to evolutionary processes, fungi, insects, plants, and crustaceans evolved blue pigmentation, but not vertebrates. While we don’t know exactly why, at least we can mimic it.
Have you ever had blue hair? I had red hair that glowed under blacklight when I was in college. It was amazing!
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Easter Egg: “I also had chin-strap facial hair, and that was not great. Well, maybe the not-so-good kind of great…”
Blue – A color that is often seen in nature and can be found in the feathers of some birds and the scales of certain fish. – The blue feathers of the peacock are used to attract mates during the breeding season.
Evolution – The process by which different kinds of living organisms develop and change from earlier forms over long periods of time. – The evolution of the giraffe’s long neck is thought to help it reach leaves high in trees.
Color – A characteristic of an object that is produced by the way it reflects or emits light, often used by animals for camouflage or attraction. – The bright color of the poison dart frog warns predators that it is toxic.
Animals – Living organisms that can move and consume organic material for energy, often playing specific roles in ecosystems. – Animals like the cheetah have evolved to run at high speeds to catch their prey.
Pigments – Natural substances produced by organisms that give color to their tissues, such as skin, eyes, and feathers. – Melanin is a pigment that gives color to the skin and helps protect it from the sun’s harmful rays.
Predators – Animals that hunt and eat other animals for food, playing a crucial role in maintaining the balance of ecosystems. – Predators like lions help control the population of herbivores in the savanna.
Feathers – Lightweight structures that cover the bodies of birds, used for flight, insulation, and display. – The feathers of a bird are specially adapted to help it fly and keep warm.
Structures – Parts of an organism that have specific functions and contribute to its survival and reproduction. – The structures of a plant, such as roots and leaves, are essential for absorbing nutrients and sunlight.
Survival – The ability of an organism to continue living and reproducing in its environment. – Camouflage is a survival strategy that helps animals avoid being seen by predators.
Light – A form of energy that is visible to the human eye and is essential for processes like photosynthesis in plants. – Plants use light from the sun to produce food through photosynthesis.
