Marine biologist David Gruber was filming coral off the Solomon Islands for National Geographic when he encountered a “bright red-and-green spaceship” – in reality, a biofluorescent hawksbill sea turtle, the first one ever discovered.
Biofluorescence is the ability to reflect the blue light hitting a surface and re-emit it as a different colour, must commonly green, red, and orange.
Biofluorescence is different from bioluminescence, in which animals either produce their own light through a series of chemical reactions, or host bacteria that give off light.
Biofluorescence is usually used for finding and attracting prey, defence or communication, scientists say, although in this case it could be a kind of camouflage in a coral reef habitat with many biofluorescing animals.