Pink is a color that occurs rarely in nature. In this article, we will examine what things in nature are naturally pink and why they have this unique coloration.
Why is pink rare in nature?
The color pink is rare in the natural world because it requires a unique combination of pigments. For an organism to be naturally pink, it must have red pigments as well as white pigments present.
The red pigments are biological molecules like carotenoids, retinoids, porphyrins, or other tetraterpenoids. These red pigments absorb green and blue light, leaving behind light in the red wavelength. Meanwhile, white structural elements like calcium carbonate or guanine crystals reflect back all visible wavelengths of light.
When red pigments and white reflective elements are present together in the right proportions, the net effect is that more red light than other wavelengths is reflected back to our eyes, creating the sensation of pink.
This combination is unusual in nature. Red pigments by themselves create shades of red, orange, or brown. White reflective elements alone produce white or silvery colors. Only when the two are mixed in the proper ratios does pink arise.
Pink plants
Although plants primarily contain green chlorophyll pigments for photosynthesis, some unusual species also produce red pigments like anthocyanins. When coupled with reflective plant cell walls, these red pigments can lend some plants and their parts a pink hue.
| Plant | Pink part |
|---|---|
| Moss campion | Flowers |
| Pink lady’s slipper | Flowers |
| Quaking grass | Stems |
| Pink snowberries | Berries |
One famous example is the moss campion, which produces bright pink flowers. This coloration may help the flowers stand out to pollinators. Other pink plant parts like stems and berries may visually attract seed dispersers.
The anthocyanin pigments also act as antioxidants, protecting the plants from too much solar radiation. So the pink color in plants can serve both decorative and protective roles.
Pink insects
While many insects have brown, black, or green coloration for camouflage, some unusual species display bright pink hues. These include varieties of butterflies, moths, grasshoppers, and treehoppers.
| Insect | Pink part |
|---|---|
| Pink underwing moth | Wings |
| Pink grasshopper | Body |
| Pink katydid | Body |
| Pink spotted hawkmoth | Wings |
In butterflies and moths, the wings contain layered structures made of chitin and air. This produces white reflectivity. When overlayed with red pigments like carotenoids, the wings can take on a pink appearance.
Other insects derive their pink hues from a red body pigment called pteridine. When deposited over a pale exoskeleton, it gives a pink coloration.
The function of pink insect coloration is not always clear. It may serve as a warning signal to predators that the insects have a bad taste or toxicity. The brightness might also support mating display rituals. More research is needed to fully understand the evolutionary purpose of pink insects.
Pink fish
While pink is rare in the animal kingdom, some striking naturally pink marine fish do exist. Most famously, the pink anemonefish lives symbiotically with sea anemones. The pink skunk clownfish is similarly pink-hued.
| Fish | Pink part |
|---|---|
| Pink anemonefish | Body |
| Pink skunk clownfish | Body stripes |
| Panamanian pink pleco | Fins |
These fish likely derive their pinkness from a combination of reflective guanine crystals overlaying reddish pigments like pteridines or carotenoids. The exact evolutionary purpose is debated, but may involve signaling or camouflage.
Interestingly, some freshwater fish like the Panamanian pink pleco also display bright pink fins and body parts. So pink fish are found in both saltwater and freshwater habitats.
Pink birds
Most bird species display colors like brown, black, or green. But some tropical species have evolved bright pink plumage.
| Bird | Pink part |
|---|---|
| Pink-necked green pigeon | Neck |
| Galah cockatoo | Chest |
| Roseate spoonbill | Wings |
For example, the pink-necked green pigeon has a bright pink neck and breast. The galah cockatoo has pink underparts and wings. And the roseate spoonbill gets its name from its bright pink wings.
In birds, pink coloration comes from carotenoid pigments overlaying white structural feathers and feather parts. The function is still being researched, but seems to relate to mating displays and social signaling.
Pink mammals
Mammals generally lack bright pink coloration. But a few unique species do display limited pinkness.
The pink fairy armadillo has a pink bony shell and snout, due to an absence of skin pigments overlaying blood vessels. The endangered pink river dolphin has some pinkness to parts of its skin and fins.
| Mammal | Pink part |
|---|---|
| Pink fairy armadillo | Shell and snout |
| Pink river dolphin | Skin and fins |
Newborn mammals like pigs, mice, rabbits, and moles can also display temporary pinkness before adult pigmentation sets in. This early pinkness stems from thin, translucent skin overlaying red blood vessels.
So in mammals, pink coloration tends to be limited. It may serve social functions in river dolphins. In other cases, it simply results from incomplete pigmentation over blood vessels near the skin’s surface.
Pink coral and shells
While animals only rarely display pink hues, some invertebrates like corals and shellfish commonly exhibit bright pink shells and exoskeletons.
| Animal | Pink part |
|---|---|
| Pink tubastrea coral | Polyps |
| Lettuce sea slug | Body |
| Pink conch | Shell |
| Netted tubeworm | Tubes |
For example, many coral polyps contain pink pigments alongside their chlorophyll, lending reefs bright pink colors. Some sea slugs like the lettuce sea slug have vivid pink bodies. Shellfish like pink conchs have pink-lined shells, while tubeworms construct bright pink tubes.
The pink pigments in these invertebrates include various carotenoids like astaxanthin. These mix with white structural elements in the shells and exoskeletons to produce pink hues that may help with camouflage, UV protection, or signaling.
Pink lakes
While pink animals are rare, pink lakes and bodies of water occur in several places worldwide. These include Lake Hillier in Australia, the Pink Terraces in New Zealand, and Havasu Falls in Arizona.
The pink color results from high concentrations of red carotenoid pigments from algae and bacteria alongside white mineral deposits containing calcium, magnesium, or sodium. When found together, these red organic pigments and white inorganic minerals make the water appear intensely pink.
| Pink lake | Location |
|---|---|
| Lake Hillier | Australia |
| Pink Terraces | New Zealand |
| Havasu Falls | Arizona |
So while water is usually blue, unusual microbial ecologies can result in spectacular pink lakes. The pigments may derive from salt-loving microbes that thrive in these mineral-rich waters.
Pink mineral deposits
Some rare pink minerals also exist in nature. Pink halite, for example, is a type of rock salt that gets its color from embedded red carotenoid microbes.
| Mineral | Source of color |
|---|---|
| Pink halite | Carotenoids |
| Rhodochrosite | Manganese |
| Rhodonite | Manganese |
Other pink minerals like rhodochrosite and rhodonite get their color from manganese. The manganese provides a red component that mixes with reflective white mineral layers to appear pink.
So while most geological formations are grey, tan, or black, occasional pink rocks and crystal deposits can form in nature. These remain rare, but provide a uniquely colorful sight in nature.
Conclusion
While pink is an unusual color in the natural world, a wide variety of organisms and landscapes can appear pink under the right conditions. For animals and plants to become pink, they must produce both red pigments and white structural elements that combine to reflect back predominantly red light. When these conditions are met in insects, fish, birds, lakes, corals, and other living things, nature dazzles us with its rare gift of natural pinkness.
