There are several species of turtle that can have bright green coloration. The most common bright green turtles seen in captivity and the wild belong to two main families: pond turtles (Emydidae) and box turtles (Terrapene). Within these families, some specific species known for their vibrant green hues include the red-eared slider, the eastern box turtle, and the Asian box turtle.
The bright green coloration serves important purposes for these turtles. The striking color helps them blend into their natural habitats of lush vegetation near ponds, lakes, and forests. It also differs from the appearance of other animals, helping the turtles identify members of their own species. For reptile enthusiasts, the vibrant green shades are one of the attractive features that make box turtles and sliders popular choices as pets.
Red-Eared Slider
The red-eared slider (Trachemys scripta elegans) is likely the most familiar bright green turtle species. Native to the southern United States and northern Mexico, these pond turtles get their name from the red markings around their ears. However, the rest of their shell and skin can display brilliant green, along with some yellow, black, and brown.
Red-eared sliders owe their green coloration to their aquatic habitat. Algae and other green plants in and around the pond help provide camouflage from predators. The green hues are also thought to come from carotenoid pigments in their diet. Sliders kept in captivity may lose some of their vibrant color over time without access to these dietary carotenoids.
While young red-eared sliders have green shells, the top shell tends to darken to olive or brown as they age. However, the bottom shell, or plastron, remains yellow-green. The skin of their heads, legs, and tails also stays green.
Physical Description
Here are some key facts about the appearance of red-eared sliders:
- Carapace (top shell) color: Greenish in young turtles, becoming brown or olive as adults
- Plastron (bottom shell) color: Yellowish green, brighter when young
- Skin color: Green head, legs, and tail
- Red ear markings: Vibrant red or orange stripe behind each eye
- Size: Adults reach 5-12 inches long
- Weight: 5-25 ounces, depending on sex and age
The carapace of the red-eared slider ranges from green to brown, while the skin and plastron maintain bright green hues. The red markings around the ears are most vibrant when they are young.
Eastern Box Turtle
The eastern box turtle (Terrapene carolina carolina) exhibits some of the most stunning green coloration of any turtle species. Sometimes known as the common box turtle, they have a domed top shell and a hinged bottom shell that allows them to completely enclose their bodies for protection.
Native across the eastern United States, eastern box turtles live in moist woodlands and floodplains. Their radiant green skin acts as camouflage in the lush eastern forests they inhabit.
While the eastern box turtle’s shell can range from brown to black with yellowish lines, their skin coloration is distinctly green. The skin on their legs and head has bright emerald or lime green hues. Eastern box turtles may also have some yellow, orange, or red markings on their heads and shells.
Physical Description
Key facts about the appearance of eastern box turtles:
- Carapace (top shell): Brown, black, or olive with yellow lines
- Plastron (bottom shell): Brown or black with yellow lines
- Skin color: Vibrant green head, legs, and tail
- Other markings: May have orange, red, or yellow on head and shell
- Size: Adults reach 4-7 inches long
- Weight: 0.5-2.5 pounds
The brilliance of the eastern box turtle’s green skin makes it unmistakable. Their shells show more individual variation in color and patterning.
Asian Box Turtle
Several box turtle species across Asia are known for their rich green coloration. One is the Asian box turtle (Cuora amboinensis), also called the Malayan or Southeast Asian box turtle. Their native range spans much of Southeast Asia, including Indonesia, the Philippines, Malaysia, and some Pacific islands.
Like other box turtles, the Asian box turtle’s high-domed top shell and fully closable bottom shell provide formidable defenses. When closed up, the turtle is protected from predators on all sides.
Asian box turtles display especially vibrant green skin, ranging from emerald to lime. Their shells tend to be black or brown with some yellow streaks. The combination of the dark shell and bright green skin helps provide camouflage in the tropical forests and ponds they inhabit.
Physical Description
Here are some main facts about the appearance of Asian box turtles:
- Carapace (top shell): Black or brown with faint yellow lines
- Plastron (bottom shell): Black or brown, may have yellow lines
- Skin color: Bright emerald or lime green skin
- Size: Adults reach 5-8 inches long
- Weight: 1-2 pounds
Like the eastern box turtle, the brilliant green skin of the Asian box turtle stands out compared to its darker shell. This coloration helps the turtle blend into the lush greenery of its tropical habitat.
Green Coloration as Camouflage
The vibrant green coloration shared by turtles like red-eared sliders, eastern box turtles, and Asian box turtles serves an important defensive purpose in nature. By blending in with green vegetation in their wetland and forest habitats, the turtles can stay hidden from potential predators.
Some key facts about green coloration as camouflage include:
- Green skin helps turtles visually merge into lush greenery of plants, grasses, ferns, and algae
- Conceals turtles from threats like hawks, foxes, coyotes, and raccoons
- Provides camouflage while basking, feeding, and moving between habitats
- Shell patterning and colors augment concealment in the undergrowth
- Young turtles tend to be greener than adults of the same species
- Darker shell colors contrast against bright green skin for disruptive patterning
This natural green camo has likely evolved over many generations to help hide turtles in their native environments from predators. Captive turtles may lose some coloring without the same diet and habitat.
Causes of Green Coloration in Turtles
While green provides essential camouflage, how do these turtles gain their verdant hues in the first place? There are several contributing factors to the vibrant green colors.
Dietary Carotenoids
Carotenoids are pigments produced by plants and algae that create bright yellow, orange, and red colors. Turtles ingest carotenoids through an omnivorous diet of:
- Algae
- Aquatic plants
- Insects
- Worms
- Berries
- Greens
These pigments are absorbed and accumulated in the turtles’ fatty tissues. Combined with blue structural colors in the skin, the carotenoids produce striking greens. Captive turtles require carotenoid-rich foods to maintain bold colors.
Structural Coloration
In addition to pigments, some of the green hues come from structural coloration. Iridophores in the skin contain nanocrystals that reflect specific wavelengths of light. The blue structural colors combined with yellow and orange carotenoid pigments create green tones.
Algae Growth
Being aquatic and semi-aquatic species, these turtles spend much of their time in and around water. Algae can grow directly on the shells and skin, literally turning the turtles green. When basking on logs or rocks, algae help further camouflage the turtles.
Age Differences
Younger turtles tend to be greener and have more vivid markings than mature adults of the same species. This likely improves their chances of survival by better camouflage from predators. Their shells and skin become darker and less vibrantly colored as they age.
Caring for Green Turtles in Captivity
The bright green colors make box turtles and red-eared sliders popular choices for pet reptiles. Providing proper care and habitat helps ensure captive turtles retain their vibrant hues. Here are some key tips:
- Supply carotenoid-rich foods like dark leafy greens, berries, flowers
- Keep clean water for swimming, allow access to natural light
- Offer an enclosure with hiding spots, logs, rocks, and live plants
- Provide full spectrum UV lighting and heating lamps
- Let them bask to dry off and absorb UV rays
- Give supplements such as calcium and vitamin D3
With attentive care mimicking their natural environments, most green turtles can maintain their lush colors in captivity. Proper diet and habitat encourages healthy shells, skin, eyesight, bones, and activity levels.
Conclusion
The most common bright green turtle species tend to come from two main families – pond turtles like the red-eared slider, and box turtles such as the eastern box turtle and Asian box turtle. Their radiant green coloration provides essential camouflage in their native woodland and wetland habitats. Carotenoid pigments from food, structural colors in the skin, algae growth, and youthfulness all contribute to the vibrant hues. For reptile enthusiasts, green coloration is part of the appeal of these popular box turtles and sliders as pets. With proper care, lighting, nutrition, and habitat, captive turtles can retain their distinctive emerald tones. When it comes to exceptionally green turtles, there are few species that can compare to the brilliance of red-eared sliders, eastern box turtles, and Asian box turtles.
References
Green Sea Turtle Facts and Information. (n.d.). Retrieved from https://seaworld.org/animals/all-about/green-sea-turtle/
Red-eared slider turtles: Popular & Controversial. (2019, June 3). Retrieved from https://www.allturtles.com/red-eared-slider/
Eastern Box Turtle. (n.d.). Retrieved from https://www.virginiaherpetologicalsociety.com/reptiles/turtles/eastern-box-turtle/eastern_box_turtle.php
Asian box turtle. (2020, August 13). Retrieved from https://en.wikipedia.org/wiki/Asian_box_turtle
What Makes a Turtle Green? (2020, August 4). Retrieved from https://www.turtleholic.com/what-makes-a-turtle-green/
How to Care for Your Green Sea Turtle. (2021, June 17). Retrieved from https://www.thesprucepets.com/green-sea-turtle-1239289