During a recent night dive near the Solomon Islands, a team of scientists were stunned to discover a glowing hawksbill sea turtle. It’s the first documented case of biofluorescence in a reptile.
Not to be confused with bioluminescence (in which animals produce light through a chemical reaction), biofluorescence is a phenomenon in which organisms absorb light, transform it, and eject it as a different color. Typically, these colors are green, red, and orange. A wide number of animals are capable of biofluorescence, including some fish, sharks, rays, copepods, and mantis shrimp. And now, as an exclusive to National Geographic, scientists have reported the first case of biofluorescence in a reptile.
Marine biologist David Gruber of City University New York was swimming with his team in the Solomon Islands this past July while trying to film biofluorescence in small sharks and coral reefs. Instead, they captured unprecedented video—which can be found here—of a large hawksbill sea turtle featuring a patchwork of neon green, yellow, and red over its head and body. As NatGeo writer Jane J. Lee explains, the only artificial illumination used during the filming was a blue light that matched the blue light of the surrounding ocean. A yellow filter on the camera was used to detect any fluorescence.
But why would a turtle evolve such a characteristic? Lee writes:
“[Biofluorescence is] usually used for finding and attracting prey or defense or some kind of communication,” says Gaos. In this instance, it could be a kind of camouflage for the sea turtle.
The hawksbill’s shell is very good at concealing the animal in a rocky reef habitat during the day, [Alexander]Gaos explains. “When we go out to catch them, sometimes they’re really hard to spot.”
The same could be true for a habitat rife with biofluorescing animals—like a coral reef.
In fact, Gruber pointed out that some of the red on the hawksbill he saw could have been because of algae on the shell that was fluorescing. The green is definitely from the turtle though, he says.
Sadly, hawksbill sea turtles are a critically endangered species, and one of the rarest on the planet. Further observations of these magnificent creatures—and their newfound ability— will not be easy.
Read the entire article at National Geographic.