There are a variety of animals that have yellow skin. The color of an animal’s skin is determined by the presence and distribution of pigments like melanin and carotenoids. Animals with yellow skin often have it for camouflage purposes or to deter predators. Some examples of animals with yellow skin include certain breeds of chicken, canaries, some tree frogs, corn snakes, ball pythons and Burmese pythons. Read on to learn more about the animals that have yellow skin and why they evolved this trait.
Chickens
Some chicken breeds have yellow skin, while other breeds have white skin. The most common breeds that have yellow skin include the Plymouth Rock, Rhode Island Red, New Hampshire, Buckeye and Jersey Giant. The yellow skin is caused by the deposition of carotenoids from the chickens’ feed into the skin tissues. Carotenoids are natural pigments that produce rich yellow, orange and red colors. They are found in many plant sources like marigold petals. Chickens cannot naturally produce enough carotenoids on their own, so they obtain them through their diet. When chickens eat feed that is rich in carotenoids, it leads to yellow pigmentation in the skin, fat and egg yolks.
So why did certain chicken breeds evolve to have yellow skin? The yellow skin likely emerged from selective breeding by humans to produce more golden colored egg yolks, which were considered more appetizing. However, yellow-skinned chickens may have some natural advantages too. The yellow skin coloration can serve as environmental camouflage since chicken domestication originated in subtropical and tropical Asia thousands of years ago. The yellow skin helped chicken breeds like the Plymouth Rock blend in with the sandy environment and avoid detection by predators. Additionally, the antioxidant properties of carotenoids may boost the chickens’ immunity against disease. Therefore, yellow skin may have helped some chicken breeds survive better in the wild.
Canaries
Canaries are small finch-like birds that are kept as pets and bred for their beautiful yellow plumage. The common canary (Serinus canaria forma domestica) is native to the Macaronesian Islands off the coast of Portugal and Morocco. Wild canaries have a greenish-yellow coloration. But after domestication, vibrant yellow and orange color variations emerged from selective breeding. This includes breeds like the Yorkshire, Border and Red-Factor canaries. The yellow skin and feathers of domestic canaries are due to carotenoid pigments obtained from their seed diet. Carotenoids are beneficial antioxidants for birds that boost immunity and reproductive health.
In the wild, the yellow plumage provides camouflage in the canaries’ native habitat of dry forests and scrublands. The color blends in with the sandy soil and desert grasses. The carotenoids may also signal the health and vitality of male canaries to potential mates. In captivity, the bright colors are considered attractive for pet owners. So breeders select for birds with deeper yellow and orange hues. Altering the proportion of seeds and fruits with carotenoids, like dandelion greens, papaya and sweet potato, in the canaries’ diet enhances the colors.
Tree frogs
Several tree frog species have striking yellow or orange skin coloration. Well-known examples include the grey tree frog (Hyla versicolor), the golden tree frog (Phytotriades auratus), and the golden poison frog (Phyllobates terribilis). The vibrant colors warn potential predators that the frog species are poisonous. The poisons, called alkaloids, are obtained through the frog’s diet and concentrated in their skin glands. While the grey tree frog’s toxins cause skin irritation, the golden poison frog carries enough venom to kill 10 grown men. When a predator attacks or a frog is under stress, the alkaloids are actively excreted as a defense.
The complexity of the skin color patterns also helps camouflage the frogs within their arboreal habitats in the tropical forests of South and Central America. The grey tree frog can shift between green and yellow hues to blend in with foliage. Meanwhile, the golden poison frog has an intricate black pattern that disguises it among the dappled light and leaf litter on the forest floor. Therefore, the yellow skin of these tree frogs serves both as a warning and as useful camouflage from predators in their natural environments. It evolved through natural selection for survival.
Corn snakes
Corn snakes have vivid orange or reddish-orange skin with darker red blotches outlined in black on the back. They are named for their resemblance to Indian corn with the colorful pattern. Corn snakes are native to the southeastern and central United States. The yellow skin helps them blend in with fallen leaves on the forest floor to avoid predators like birds of prey. When threatened, corn snakes can temporarily intensify their colors and form stripes as a warning. Their vibrant appearance mimics the coloration of venomous coral snakes, fooling predators into thinking the non-venomous corn snake is dangerous.
Interestingly, corn snakes used to have naturally greyish or brown skin coloration before selective breeding in captivity produced the more vibrant orange and red varieties. The skin color is determined by pteridines, which are pigments that reflect light to produce red, yellow and orange hues. Breeders select for snakes with increased pteridines to create brighter skin colors for pets. However, even in duller-colored wild snakes, the skin coloration still serves as crypsis camouflage and mimicry of venomous species when needed for defense.
Ball pythons
Ball pythons, also called royal pythons, are native to West and Central Africa. They get their name from their tendency to curl into a ball when stressed. Their skin is patterned with creamy-yellow to brown blotches on a dark brown background. Like corn snakes, ball pythons rely on their coloration to disappear against the forest floor strewn with dead leaves and wood. The blotchy pattern breaks up the snake’s body outline, masking it from potential predators. When threatened, ball pythons may hiss loudly or twitch their tails while hidden to startle attackers with a bluff that they are dangerous.
In recent years, captive ball python breeding has produced color morphs with enhanced yellow on more of the snake’s body. Selective breeding focuses on recessive genetic mutations leading to pleasing color variations for the pet trade, like the pastel, lemon blast and ivory morphs. However, these brighter colors likely wouldn’t provide the same survival advantages as the naturally camouflaging muted yellow and brown hues do in the wild.
Burmese pythons
The Burmese python is a large constrictor snake native to Southeast Asia. Adults can reach up to 20 feet long. Their skin is yellowish to tan with darker brown blotches outlined in black down the back. The belly is whitish or yellow. Just like ball pythons, the color pattern allows Burmese pythons to disappear amongst the dead leaves and woody debris of their jungle habitat to avoid predators and ambush prey. When threatened, they may try to blend in by hiding their heads and flattening their bodies.
Yellowish skin coloration likely helps camouflage young Burmese pythons too. Hatchlings are more vulnerable to predation until they reach an imposing adult size. Additionally, the yellowish tones combined with dark markings help break up the python’s outline so their movements attract less attention from prey. Therefore, the yellow skin of Burmese pythons plays an important role in their ability to survive in the wild through crypsis.
Conclusion
In summary, yellow skin coloration has evolved in different animals for camouflage and warning coloration. Chickens likely developed yellow skin from selective breeding by humans but the color also provided some natural advantages. Bright yellow plumage in canaries originated for mate selection but also blends into the environment. Poisonous tree frogs use their yellow skin to warn predators, while still disguising themselves in the rainforest. Snakes like corn snakes, ball pythons and Burmese pythons rely on yellowish skin with dark blotches to mimic dead leaves on the forest floor as camouflage. So in most cases, yellow skin evolved to help these animals survive predators and capture prey. It serves essential natural purposes for the animals beyond aesthetic appeal to humans. Understanding why certain color traits develop can provide fascinating insight into species’ adaptations and the pressures of natural selection.
References
- Hill, G. E. (2002). Red Bird in a Brown Bag: The Function and Evolution of Colorful Plumage in the House Finch. Oxford University Press.
- Oliphant, L. W. (1968). Colours of the Canary. The Canary Breeder’s Handbook.
- Duellman, W. E., & Trueb, L. (1994). Biology of Amphibians. JHU Press.
- Bechtel, H. B. (1995). Reptile and Amphibian Variants: Colors, Patterns, and Scales. Krieger Publishing Company.
- Bartlett, P., & Wagner, E. (1997). Corn Snakes: The Comprehensive Owner’s Guide. Barron’s Educational Series.
- Barker, D. G. (2006). Ball Pythons: History, Natural History, Care, and Breeding. VPI library.
- Murphy, J. C., & Henderson, R. W. (1997). Tales of Giant Snakes: A Historical Natural History of Anacondas and Pythons. Krieger Publishing Company.
| Animal | Yellow Skin Adaptation |
|---|---|
| Chickens | Camouflage, mate selection |
| Canaries | Camouflage, mate selection |
| Tree frogs | Warning coloration, camouflage |
| Corn snakes | Camouflage, mimicry |
| Ball pythons | Camouflage, mimicry |
| Burmese pythons | Camouflage |
