This hawksbill is fluorescent, which is something hawksbills aren’t really known to be. It’s not glowing, like a firefly or that weird plankton that turns tides blue — that’s bioluminescence.
No, it’s biofluorescent, according to marine biologist David Gruber, who shot this video. The way it works is, rather than producing its own light, the turtle’s shell reflects blue light as red and green — something you can see is clearly not happening with this hawksbill.
Researchers have recently discovered biofluorescence in some fish and crustaceans but never a reptile like the hawksbill.
While biofluorsecence is used in some animals to attract prey, hawksbills largely feed on sponges and algae, so a more likely hypothesis — as another marine biologist told National Geographic — is camouflage.
Still, it’ll take more research to understand — something that might not be possible with the hawksbill, which is critically endangered.