When marine biologist David Gruber visited the Solomon Islands in July to study biofluorescence, he never expected to find the glowing phenomenon in a sea turtle. No other reptiles are known to exhibit this colorful quality, and the glowing hawksbill sea turtle he filmed marks the first ever biofluorescent reptile known to science.
"It almost looks like a bright red and green space ship came right underneath my camera," he told National Geographic.
While bioluminescence is the ability for animals to produce their own light through chemical reactions, biolfluorescence occurs when an organism reflects blue light hitting a surface and reproduces it as a different color. The occurrence has been observed in a number of fish, corals, sharks, rays, mantis shrimp, and tiny crustaceans called copepods. It’s normally used as a method for attracting prey or as some form of communication, but it’s still too early to say how exactly it benefits the hawksbill.
One possible explanation is that the same shell that provides an impressive camouflage during the day could light up at night as a way of helping the turtles blend in with the fluorescent coral reef. Corals are the only other organisms that have been observed producing multiple glowing colors, but Gruber points out that the turtle's red color may be the product of fluorescent algae on its shell. Even if that’s the case, he says the turtle’s neon green markings are definitely the real deal.
Hawksbill sea turtles are one of the rarest species on the planet, with their worldwide populations having dwindled by 90 percent in just the past few decades. It’s difficult to study a species when it’s so endangered, so Gruber plans to seek out answers to the questions his discovery raised by looking at the green sea turtle, a close relative of the hawksbill.
[h/t: National Geographic]