During a night dive in the Solomon Islands, marine biologist David Gruber chanced upon a glowing sea turtle, the first discovery of biofluorescence in a reptile.

Observed in a number of animals that include fish, sharks and jellyfish, biofluorescence is the ability to absorb and reflect light and emit it in a different color, usually green, red and orange.

Gruber’s discovery of the hawksbill sea turtle glowing in the dark is the first record of this phenomenon in a reptile.

An assistant professor of biology and environmental science at the City University of New York, Gruber was filming biofluorescence in small sharks and coral reefs in the Solomon Islands when the scene unfolded before him.

“[T]here came out of nowhere this fluorescent turtle,” recalled Gruber of the night dive when he and his team were watching out for crocodiles frequenting the location.

He described it as an alien craft with patches of neon green and red on its head and body.

Gruber captured the biofluorescent turtle sighting on his video camera and followed the turtle for a short time. “[A]fter a few moments I let it go because I didn’t want to harass it,” he said.

The marine biologist connected with a community nearby that kept a number of captive young hawksbills, examined them for a similar ability, and discovered they all glowed red.

Alexander Gaos, director of the Eastern Pacific Hawksbill Initiative, was not part of the accidental find but found it “really quite amazing.”

“I don’t think anyone’s ever seen this,” said the expert, who has been studying turtles for a long time now.

According to Gaos, biofluorescence is typically used to find and attract prey, or as a form of defense or communication.

In the case of the turtles, being biofluorescent might help confuse predators or camouflage them while they swim among glowing corals.

The exact answer, however, may remain elusive: hawksbill sea turtles are already critically endangered, with some populations continually at risk of extinction due to human fishing and poaching.