Glow in the Dark Animals

Glow in the dark is a popular phrase used to describe toys, stickers and other things that glow when you shine a special type of light on them. But it turns out there are some animals that can glow in the dark too, and they use this glowing ability for a variety of purposes including protection, hunting and even communication.

Many different types of marine creatures glimmer in the dark thanks to a phenomenon called bioluminescence. This occurs when specialized cells within an animal create a light through a chemical reaction. Marine animals that glimmer include some fish, squid, octopuses, jellyfish and sharks. They use their glimmer to warn predators, lure prey or even to signal to mates.

Some of the earliest glow-in-the-dark creatures may have been corals in the deep ocean, according to a new study. The researchers found that corals in the deep sea began to glow 540 million years ago—far earlier than previously thought. “Lighting is one of the earliest forms of communication that we know of and it’s very important in deep waters,” says study co-author Andrea Quattrini of the Smithsonian National Museum of Natural History in Washington, D.C.

Another type of glowing creature is the plankton, tiny single-celled organisms that create a ruddy red tide during the day. These organisms aren’t as exciting as a unicorn or Sasquatch, but they play an important role in the food chain by attracting other creatures that will eat them.

Even humans have a way of shining in the darkness, at least when they are wearing brightly colored clothing. This is because the skin pigment known as melanin absorbs certain frequencies of light and reflects other wavelengths. People can see this glowing effect when they hold their hands up to a mirror in the dark.

Most animals don’t glow in the dark, but some do have eyes that seem to reflect light. These animals have a reflective structure in their eyes called the tapetum lucidum. The reflection can give an animal a nice glow at night, making it more visible to predators. This is a useful defense mechanism in some species, such as deer, raccoons and some cats.

Interestingly, some domestic dogs and cats appear to have eyes that glow in the dark as well. Scientists have discovered that a gene in the cat family allows their eyes to glow, but it is not turned on during the daytime. This is probably a survival trait that was not necessary when the cat family evolved.

It was a fluke that led to the discovery of the first glow-in-the-dark mammal. Forestry professor Jon Martin was using a UV flashlight to scan his Wisconsin forest at night when he noticed that a flying squirrel munching on the bird feeder was shining pink. This turned out to be a good thing because it turns out that the three species of New World flying squirrel (Glaucomys) fluoresce, or glow, with swirls and patches of pink and blue in the dark. The fur of African springhares, a small mammal that looks like a cross between a rabbit and a kangaroo, also glows in the dark.