Wider World Of Glow-In-The-Dark Life Forms

A few years ago, scientists believed only a tiny band of creatures could emit light. But a string of new discoveries has illuminated a wider world of glow-in-the-dark life forms

- Jules Howard

DEVIL MAKES LIGHT WORK

“It was pretty shocking when we saw it,” Jacob Schoen, a technician at an Ohio zoo told local reporters in December 2020, just before the global media circus descended. The source of this storm? This image, clearly showing that the Tasmanian devils housed in their enclosure were fluorescing after-hours – parts of their faces were, quite literally, glowing in the dark. Certain Australian mammals, including Tasmanian devils, are thought to manage this via arrangements of special proteins in the skin and fur that absorb energy from sunlight during the day. At dusk, they re-emit this energy in a different wavelength – one invisible to humans without the use of blacklights or ultraviolet (UV) torches, which translate these hidden wavelengths into colours our eyes can process. The big question zoologists are now asking is: why? What role does fluorescence play in animal communication? Week-by-week, month-by-month, other animal discoveries are lighting a path towards answers.

GLOW IN THE SHARK

“This isn’t a small shark trying to blend in with the dim, inky light of the twilight zone to avoid getting eaten, but a big predator that maybe even illuminates the seabed to hunt down prey,” says Dr Helen Scales, marine biologist and author of