It sounds like something otherworldly, fit for a fairy tale: a glowing sea turtle. But this creature is real. Previously unknown to science, it appears that some hawksbill sea turtles are capable of biofluorescence. A team of scientists recently became the first to witness such an animal during a dive off the Solomon Islands.
The scientists, who went looking for better known biofluorescent creatures such as corals and some fish, were stunned when the luminous sea turtle came swimming up to them, radiating with neon greens and reds.
Because the researchers were carrying special equipment for viewing natural biofluorescence — a blue light that matched the blue light of the surrounding ocean, and a camera with a yellow filter — they had a truly unique opportunity to film the glowing turtle in all of its glory. You can view that video exclusively at National Geographic here.
"I've been [studying turtles] for a long time and I don't think anyone's ever seen this," said Alexander Gaos, director of the Eastern Pacific Hawksbill Initiative, to National Geographic. "This is really quite amazing."
The sea turtle represents the first known case of biofluorescence in a reptile. Biofluorescence, which happens when organisms absorb light, transform it, and radiate it as a different color, is not to be confused with bioluminescence, which typically involves a chemical reaction where organisms actually produce their own light. Scientists are only just beginning to explore the vibrant world of biofluorescence in nature, a phenomenon that had been largely overlooked in the past. This sea turtle is a startling reminder of just how much more there may be to discover.
So far it is unclear if this glowing ability is unique to a small population of hawksbill turtles swimming around the Solomon Islands, or if it is more widespread among hawksbills everywhere and other sea turtles. This is the only wild hawksbill ever discovered with the ability, but divers rarely, if ever, carry the proper equipment to capture it. Researchers did test some nearby captive young hawksbills being kept by a local community, and they also glowed red. More research is needed before any broader claims can be made, however.
It's also too early to tell how the turtles use their biofluorescence. It might help camouflage them as they swim among similarly glowing corals, or it may serve to confuse predators. Some fluorescent organisms use their show of lights as a form of communication, and that possibility can't be ruled out for the turtles yet either.
Sadly, these animals could disappear before we get all the answers. Hawksbill sea turtles are critically endangered, and some populations continue to be threatened with extinction by human fishing practices and poaching. It would be a shame to see these brilliant animals peter out at the very moment we are just discovering how brightly they shine.