You’re floating in the warm waters of the South Pacific, and as you glance into the world below, you notice a glowing shimmer of green, red, and orange. No, it’s not long lost treasure you’ve spotted; it is the critically endangered hawksbill sea turtle, which recently earned the distinctive honor of being the first documented biofluorescent reptile. And here’s hoping that this newly-discovered ability may help bring the species the necessary attention and support it needs to survive.
A biofluorescent organism has the ability to reflect blue light while changing the color of the rays. This is distinct from bioluminescne, the ability of an organism to emit light directly from their body. Scientists have previously documented biofluorescence in other undersea creatures like sharks, coral and shrimp. However, even the most dedicated hawksbill watchers did not expect it to possess this charismatic quality. “I’ve been [studying turtles] for a long time and I don’t think anyone’s ever seen this,” says Alexander Gaos, director of the Eastern Pacific Hawksbill Initiative “This is really quite amazing.”
The turtle’s reflective powers were first noticed by marine biologist David Gruber and his team from City University of New York when they were conducting a night dive in the Solomon Islands. While filming biofluorescent sharks and coral reefs, they noticed what looked like an alien spacecraft, lighting up the water with red and green lights. Upon closer inspection, the researchers identified the swimming object as a hawksbill.
Gaos says that biofluoresence is “usually used for finding and attracting prey or defense or some kind of communication.” For the hawksbill, biofluoresence may serve as camouflage. “When we go out to catch them, sometimes they’re really hard to spot,” says Gaos. For Gruber and his team, this amazing ability has prompted a torrent of questions: how does the turtle come to possess such an ability? Can other turtles see the reflected light? Are other sea turtle species also biofluoresent? The hawksbill turtle is a difficult subject to study due to its low numbers, which have declined by ninety percent in the past several decades. However, the team thinks that it can utilize the more common but closely related green sea turtle as it explores these questions.