A collection of never-seen-before photos showing an array of reptiles, amphibians and invertebrates ‘glowing in the dark’ have been released by experts at Chester Zoo.
Taken at the zoo at night, the photos show animals displaying vivid shades of red, blue and green under ultraviolet light, in a spectacular show of biofluorecence.
While this phenomenon is widespread among animals – and is caused by several different proteins, pigments and chemical reactions in the skin – little is currently known about why it occurs.
Dr Gerardo Garcia, Curator of Lower Vertebrates and Invertebrates at the zoo, offers several theories on why it may happen;
“I have worked closely with many these species for more than 30 years, but never before have I seen them in this way. Seeing these different animals glow in a spectacular range of colours really is incredible, but the question remains – why do they glow?
“Communication is everything in the animal world, and how a species presents itself visually is a big part of how they speak to friends and foes. There are hundreds of frequencies of light and how animals see light, and therefore colours, is different to humans. We actually only see a small portion of the sunlight, so although we may see an animal glowing brilliantly, their own kind, and even other species, may see this completely differently as they read a wavelength that our eyes can’t perceive.”
Dr Garcia says another likely reason for the fluorescent glow is to attract a mate – by helping to catch the attention of potential partners by highlighting their impressive assets. The photos show that only some parts of the animals, such as a claw or an eye, glow – and there may be a good reason for this.
Another theory for an animal’s ability to glow is to mark its territory to others. This is mainly to communicate their social status and ownership, which can help attract a partner and warn off competitors.
Animals also use colour change to hide from or pose as predators, as Dr Garcia explains:
“Some fish may use their ability to change colour to hide from predators. So, instead of them standing out to potential mates, they could glow to help camouflage. Some even go as far as posing as a particular species’ mate when, in fact, they’re its predator.”
Main image: Boxer shrimp © Chester Zoo