Green is an incredibly common color in the animal kingdom. It can serve many purposes, from camouflage to signaling toxicity. Many animals have evolved green coloration through natural selection to better survive in their environments. In this article, we will explore some of the most notable green animals and examine why they are green.
Camouflage
One of the most common reasons animals have green coloration is for camouflage. Blending in with leafy or grassy environments can help prey animals avoid detection by predators. Some examples of green animals that use their color for camouflage include:
Insects
Many insects have green coloration that helps them blend into plants and foliage. This includes grasshoppers, katydids, leaf insects, stick insects, and some species of praying mantis. Their green coloration makes them very difficult to spot when they are sitting motionless amongst vegetation.
Frogs
Several species of frog have green skin, like the green tree frog and green and black poison dart frog. Their green hue allows them to seamlessly blend into the rainforest environment. This helps them avoid predators and also sneak up on insect prey.
Lizards
Small lizards like green anoles and green tree skinks have excellent green camouflage. They can quickly change their color to match the foliage around them as they move through the trees and shrubs. This helps conceal them from both predators and prey.
Snakes
Some species of snake like the green tree python and green vine snake have vibrant green coloring. This allows them to blend in perfectly to the rainforest canopy as they lay waiting silently for passing prey. Their green color disguises them among the leaves and branches.
Warning Coloration
While green is commonly used as camouflage, it can also serve as a warning. Bright green coloration can signal toxicity in some species. Predators learn to associate the bright green colors with danger. Some good examples include:
Poison Dart Frogs
Poison dart frogs like the green and black poison dart frog have extremely toxic skin secretions. Their vibrant green coloration warns predators to stay away and prevents the frogs from being eaten. This allows populations to thrive.
Monarch Butterfly Caterpillars
Monarch caterpillars feed exclusively on milkweed which makes them toxic. Their bright green and yellow stripes serve as a warning to predators to stay away. This helps protect the vulnerable caterpillars.
Green Tree Pythons
While the green tree python does use its color for camouflage, its bright green can also signal its dangerous bite. Predators learn to be wary of the striking green snake.
Signaling
Beyond camouflage and warning, green can also serve in signaling to other members of a species. Usually this green signaling helps with mating. Examples include:
Mandrills
Male mandrills have brightly colored faces with stripes of red, blue, and green. The green signals health to potential mates. Females preferentially choose males with brighter green coloring.
Parrots
Some parrot species like macaws and conures have bright patches of green in their plumage. This green coloration is thought to help attract mates. Individuals with brighter, bolder green may have higher reproductive success.
Dragonflies
Male dragonflies have brightly colored patches on their wings. Vivid metallic greens signal strength and health to potential mates. Females seem to prefer males with bolder green wing patterns.
Structural Coloration
While most green animals get their color from pigments, some get it structurally from the physical structure of their feathers, scales, or exoskeletons. This creates iridescent or metallic greens. Examples include:
Peacocks
The famous long tail feathers of peacocks contain no green pigment. Instead, they have a nanostructure that reflects green and blue light. Small changes to the structure shifts the color across the spectrum.
Butterflies
Butterfly wings contain transparent scales that produce colors through structural coloration. Their wings aren’t actually colored pigments, but specialized structures that reflect specific wavelengths of light.
Beetles
Some beetles have metallic green elytra (wing covers). This green iridescence comes from the nanostructure of their exoskeleton rather than green pigments. Tiny physical variations alter the reflected color.
Diet
In some herbivorous animals, green coloration actually comes from their chloroplast-rich diet. By accumulating green plant pigments, their bodies also become greenish. Examples include:
Katydids
Katydids are plant-eaters, feeding on green leaves and stems. The chlorophyll pigments from their food accumulate in their tissues, giving katydids a greenish hue.
Green Sea Turtles
Green sea turtles get their name from the greenish color of their fat and cartilage. This green tint comes from the algae and sea grasses these turtles eat. What they ingest colors their tissues.
Woolly Bear Caterpillars
Woolly bear caterpillars become slightly greenish because of the green plant tissues they consume. Carotenoids from chloroplasts are incorporated into the hairs and body, tinting them green.
Algal Symbionts
Some marine animals partner with green algae, which lives inside their cells. The algae’s green photosynthetic pigments color the animal’s tissues green. Examples include:
Green Hydra
Green hydra have tentacles dotted with symbiotic algae. The algae produce food through photosynthesis and in return gain safety and nutrients. The algae’s green color tints the transparent tissues of the hydra.
Green Sea Slugs
Some sea slugs take up algal chloroplasts and incorporate them into their cells. The slug benefits from the ability to photosynthesize! The green color comes from the algae now inside the slug.
Coral
Coral polyps have a symbiotic relationship with green algae called zooxanthellae. The algae live inside the coral tissue, producing food through photosynthesis. The green color of the algae tints the coral’s tissues.
Conclusion
As we’ve seen, green coloration has evolved in animals for a variety of reasons. Camouflage, warning coloration, signaling, structural colors, diet, and symbiotic algae can all produce green in the animal kingdom.
Green is perfect camouflage in leafy environments. It can help prey animals hide from predators. But it can also serve as a warning sign of toxicity. Beyond concealment and caution, green can signal health and vigor. Structural colors can reflect stunning metallic greens. A green diet or algal partners can also tint an animal’s body.
So whether they are insects, reptiles, birds, fish or invertebrates, many denizens of the natural world have evolved green hues. This versatile color helps them survive and thrive in diverse habitats across the planet. Green truly is the color of life.
| Category | Examples |
|---|---|
| Camouflage | Insects like grasshoppers, katydids, and mantises. Frogs like green tree frogs. Lizards like green anoles. Snakes like green tree pythons. |
| Warning coloration | Poison dart frogs, monarch caterpillars, green tree pythons |
| Signaling | Mandrills, parrots, dragonflies |
| Structural coloration | Peacocks, butterflies, beetles |
| Diet | Katydids, green sea turtles, woolly bear caterpillars |
| Algal symbionts | Green hydra, green sea slugs, coral |
