Biofluorescence is a process by which creatures absorb light, transform it, and then project it as a different color. This is different than bioluminescence, in which creatures create light, or host bacteria which create light. Until now, we’ve only seen biofluorescence in coral, mantis shrimp, copepods, and some species of fish. Now though, we’ve learned that hawksbill sea turtles can also fluoresce. That’s not something we expected to see in marine reptiles.

Sea turtle

David Gruber, of City University of New York, made the discovery quite by accident while studying coral reefs around the Solomon Islands. He was filming with a camera that puts out a blue light which matches that seen in the ocean, and which happened to have a yellow filter. That filter allowed the camera to pick up the biofluorescence of a hawksbill sea turtle that just happened to swim past.

The image is quite amazing, and it’s not something we knew these turtles could do. According to Alexander Gaos, who is director of the Eastern Pacific Hawksbill Initiative, this is something totally new.

Gruber now has a lot of questions about this phenomenon, but those will require more study in the future. After a few minutes, he stopped following the turtle, so as not to disturb it, and returned to his coral study. He wants to know whether these turtles can see this biofluorescence, as well as how they developed this ability, how they’re using it, and if any other turtles can do this.

Answering those questions about the hawksbill sea turtle might be difficult, as they are extremely rare and very protected, so working with them isn’t easy. The green sea turtle is a related species, and if any other turtles can fluoresce, they would be likely candidates. Green sea turtles are also more common, and less protected, making it easier for scientists to do research on them.