No, there are no blue sea turtle species. All 7 species of sea turtles have shells and skin that range in color from yellowish to black, brown, reddish, olive green, or gray. While no sea turtles are naturally blue, there have been rare instances of individual turtles being blue due to chromatic aberration or viral infections. Overall though, blue is not a natural color for any sea turtle species.
Overview of Sea Turtle Species and Colors
There are 7 species of sea turtles in the world:
- Green sea turtle – Shell is brown or olive green, skin is greenish
- Hawksbill sea turtle – Shell is amber or brown/black, skin is yellowish or brown
- Kemp’s ridley sea turtle – Shell is grayish green, skin is greenish or gray
- Loggerhead sea turtle – Shell is reddish brown, skin is yellowish brown
- Olive ridley sea turtle – Shell is grayish green, skin is grayish green
- Leatherback sea turtle – Shell is black or dark gray, skin is black or dark bluish
- Flatback sea turtle – Shell is grayish green or olive, skin is grayish
As you can see, the natural shell and skin colors for all sea turtle species range from yellowish to black, brown, reddish, olive green, or gray. There are no bright or vivid blue sea turtles among the 7 species.
Do Any Sea Turtles Naturally Have Blue Shells or Skin?
No sea turtle species naturally has blue as a predominant shell or skin color. Here is a breakdown of the shell and skin colors for each species:
Green Sea Turtle
The green sea turtle has a smooth, oval carapace (top shell) that is brown or olive green in color. Its plastron (bottom shell) is whitish or pale yellow. The skin of green sea turtles is generally grayish green.
Hawksbill Sea Turtle
The hawksbill sea turtle has a carapace that is amber or a brownish/black hue, with streaks of orange, red, and/or black. Its plastron is predominantly yellow. The skin of hawksbills is typically yellowish or brownish in color.
Kemp’s Ridley Sea Turtle
The Kemp’s ridley sea turtle has a grayish green colored carapace and plastron. Its skin pigmentation is also grayish green overall.
Loggerhead Sea Turtle
Loggerhead sea turtles have a reddish brown carapace and a pale yellowish plastron. The skin is primarily light to medium brown with some yellowish tones.
Olive Ridley Sea Turtle
The olive ridley sea turtle has a grayish green carapace and plastron. Its skin is also grayish green in hue.
Leatherback Sea Turtle
The leatherback sea turtle has a smooth, black rubbery shell comprised of thick, leathery skin and small bones. Their plastron is whitish to pale pink. Leatherback skin is predominately blackish with some pale spotting, with a pinkish white or pale bluish undertone.
Flatback Sea Turtle
The flatback sea turtle’s carapace is grayish green to olive in color, while its plastron is pale white to yellowish. The skin has a grayish pigmentation.
As demonstrated, the natural shell and skin colors for all 7 species consists of dark blackish, brownish, yellowish, grayish, greenish, and reddish hues. Blue is not a naturally occurring prominent color in any sea turtle species.
Are There Any Rare Cases of Blue Sea Turtles?
While no sea turtle species is naturally blue, there have been a few extremely rare instances of individual turtles exhibiting partial blue coloration:
Blue Skin from Viral Infection
In 2008, a green sea turtle in the Cayman Islands was observed with partially blue skin on its head, neck, and flippers. Researchers determined this was caused by a herpes-like virus that triggered the abnormal blue skin pigmentation. However, this viral infection and resulting blue coloration is highly unusual in sea turtles.
Blue Skin from Chromatic Aberration
In 2015, a juvenile green sea turtle was spotted off the coast of the Great Barrier Reef with blue and reddish skin coloration. This was found to be caused by chromatic aberration – an error in cell pigmentation distribution. Like the viral infection case, chromatic aberration producing blue skin is exceptionally rare in sea turtles.
No Genetically Blue Species
While individual turtles may sporadically display partial blue coloration from infections or genetic mutations, there is no sea turtle species that has genetically blue skin or shells across the entire population. Blue is simply not a natural color that occurs in sea turtles species on a broad scale.
Why Don’t Sea Turtles Have Blue Coloration?
There are a few key reasons why blue coloration does not naturally occur in sea turtles:
Lack of Blue Pigments
Sea turtles lack blue pigment cells called chromatophores that would be required to produce bright blue hues. Their chromatophores only produce black, brown, red, yellow, and greenish pigments.
Camouflage
From an evolutionary perspective, blue coloration would not provide effective camouflage for sea turtles in their oceanic environments. Blues and purples stand out, while greens, browns, and grays provide better camouflage among kelp forests and coral reef habitats.
Temperature Regulation
Darker blacks, greens, and browns help sea turtles absorb heat, while lighter greens, yellows, and whites reflect heat – an important adaptation for temperature regulation in changing ocean conditions. A vivid blue shell would not properly regulate temperature.
Protective Coloration
The brown, green, gray, and blackish colors act as a protective coloration by blending in with surroundings. This makes it harder for predators to spot sea turtles. A bright blue shell or skin would be highly visible and put turtles at greater risk of predation.
Do Any Sea Turtle Hatchlings Have Temporary Blue Color?
Sea turtle hatchlings may occasionally have temporary blue coloration right after emerging from their nests, but this quickly fades:
- The amniotic sac around hatchlings may impart a bluish tint immediately after birth.
- Initial wetness on the shell from emerging can also make it appear bluish, which dries to reveal the normal color.
- This temporary blue hue fades within hours as hatchlings dry off and is not their true color.
So while newborn sea turtles may initially appear somewhat blue, this is just a short-lived effect from birth fluids and does not persist as their normal color.
Conclusion
In summary, there are no naturally blue sea turtle species. The 7 species of sea turtles all exhibit natural shell and skin colors in greenish, yellowish, brownish, grayish, blackish, and reddish hues. While a few individual turtles have been observed with partial blue skin due to chromatic disorders or viral infections, this is exceptionally rare. Evolutionarily, blue coloration would not properly camouflage, regulate temperature, or protect sea turtles. Temporary blue color right after hatching also quickly fades to normal species coloration. So while sea turtles may show some fascinating rare colors, vivid blue is not among the diverse palette of a sea turtle’s natural colorations.
| Sea Turtle Species | Shell Color | Skin Color |
|---|---|---|
| Green sea turtle | Brown or olive green | Greenish gray |
| Hawksbill sea turtle | Amber, brownish black | Yellowish or brownish |
| Kemp’s ridley sea turtle | Grayish green | Greenish gray |
| Loggerhead sea turtle | Reddish brown | Yellowish brown |
| Olive ridley sea turtle | Grayish green | Grayish green |
| Leatherback sea turtle | Blackish | Blackish with pinkish undertones |
| Flatback sea turtle | Grayish green or olive | Grayish |
