The fauna is full of interesting organisms that have the ability to glow. Most people are aware of the humble fireflies, but the vast majority of glowing animals actually hide deep in the oceans. If you’ve ever dared to dive into a submarine, sometimes you can spot ghostly shimmers looming against the dark backdrop of the vast underwater depths. These marine organisms look a bit like an alien spaceship or some strange technology. But the main purpose of the glow is much more traditional: it has evolved to attract mates, lure prey, confuse predators, or communicate with other members of the same species.
There are two main ways that animals emit light. The first method is to absorb light from the environment and then emit it back. This process is known as biofluorescence. The second method, known as bioluminescence, occurs when an animal emits light on its own. This requires a complex chemical reaction, often involving a special class of proteins called luciferase, produced in a separate light-producing organ. The chemical reaction produces cold blue, green, or yellow light (rarely red) that gives off little heat. If he really did give off heat, he would probably kill the body. Most animals, including humans, emit a small amount of light, but it is usually so subtle that only a specialized camera can capture it. However, the 10 animals on this list are some of the most notable light animals in the entire world.
# 10 The animal that glows in the dark: Fireflies
Fireflies (also known as lightning beetles) are a family of about 2,000 known land-based species. In summer, they light up the night sky with their amazing bioluminescent ability. The main purpose of the glow is to attract partners. It has been demonstrated (in at least a few species) that females choose their mates based on the intensity and frequency of their bursts. The glow also serves as a warning to predators. Because of its rather unpleasant taste, predators may think twice before trying to eat it again. A firefly can control a chemical reaction by adding oxygen to a light-emitting organ in its body. Oxygen reacts with other compounds (including luciferase) to form light. They first developed this ability back when dinosaurs were still roaming the planet. Unfortunately, they do face a number of modern threats, including the use of pesticides and the clutter caused by artificial lighting.
No. 9 The animal that glows in the dark: bioluminescent fungal mosquitoes
These insects in the larval stage are called fireflies, but this name is incorrect. In fact, these are not worms at all, but rather midges. In fact, they are members of the fly squad. They also have a unique bioluminescent ability that is not found anywhere else in the animal kingdom. Native to Australia and New Zealand, the larvae are attached to the ceiling of a cave or the bottom of a rock. They create thin, slimy filaments that hang from the ceiling and radiate an unearthly beauty, but their true purpose is to attract prey such as spiders and midges. As soon as the victim is in the mucus, the larvae eat it whole. However, this is only a temporary solution. Having reached adulthood, the mosquito loses its ability to glow and looks more like a typical flying insect.
# eight The animal that glows in the dark: angler fish
Angler fish (a whole squad of animals, numbering more than 200 species) look like terrible deep-sea predators that cause nightmares. But this terrible looking fish has an amazing bioluminescent organ. The long, sinewy bait that stretches like a pole from the female’s back is actually a modified dorsal fin. The end of the bait lights up thanks to the bioluminescent bacteria living inside the angler fish. This symbiotic relationship between fish and bacteria probably came about by accident, but it’s also a convenient shortcut; fish do not need to build a bioluminescent system from scratch.
The main purpose of the bait is to attract prey. Animals are naturally attracted to bright light, and it’s no coincidence that the bait is within reach of the grizzly’s teeth. But he has another important purpose: the light helps the female to find a suitable match for herself in the dark depths of the ocean. Angler fish mating is an interesting phenomenon in itself. Males are so different from females that they look almost like different species. Once they find a suitable mate, the male will actually merge with her body, forming a unique symbiotic relationship.
However, angler fish are not the only marine animal to have bait. An unbound viper has a similar rod-like tool that attracts prey with its magnificent light. Once they are within reach, the snake immobilizes and catches its prey with its long, fang-like teeth. This animal can also emit bluish light around its abdomen through specialized organs called photophores. It is believed that the glow can serve to hide the silhouette of fish from dangerous predators against the dim blue light of the water.
# 7 The animal that glows in the dark: Jellyfish
The humble jellyfish is perhaps the most bioluminescent animal on the planet. It is estimated that about half of the approximately 2,000 known species have some kind of luminous ability. Most often, jellyfish use light to escape predators. Some jellyfish emit bright flashes to scare predators, while others release glowing particles or decoys to distract them.
# 6 The animal that glows in the dark: Krill
Krill are tiny marine crustaceans, most of which are no more than one to two inches long. They are very common prey for larger marine organisms such as whales, which kill them in the thousands. These inconspicuous organisms also have an amazing ability to emit light from their bodies. Some species even have special rotating lenses that direct light to a specific area. The reason for this is unclear. It may have something to do with sexual or school behavior.
# five Glow-in-the-dark animal: bioluminescent sharks
It is estimated that around 57 species, or just under 10% of all sharks, may emit some kind of light. The most famous, perhaps, is the lantern shark. This small animal hides in a deep, dark sea, using glow to mask the faint blue light of its surroundings. In March 2021, scientists also discovered that a great predatory shark called a kitefin can also emit light. Ranging from 3 to 5 feet, it is the largest known bioluminescent vertebrate ever discovered. Unlike most bioluminescent sharks, which have glowing undersides that merge with them underneath, a kitefin’s entire body can emit light. The purpose of this is not yet fully understood.
# 4 The animal that glows in the dark: the firefly squid
While only a few squid species are capable of catching fire, fireflies are an impressive exception. These tiny animals, about 3 inches long, spend the winter living in the deep sea. In the summer, they travel to their spawning grounds off the coast of Japan, where they put on a spectacular light show, probably to interact with comrades and rivals. These squids emit blue light through a complex organ called photophores throughout their body. This body is equipped with lenses, shutters, colored filters and reflectors. By controlling these organs, the squid can emit light in any way it wants. Unfortunately for them, their bright glow makes them easy to catch in large numbers. In Japan, they are considered a culinary delicacy.
# 3 The animal that glows in the dark: Sea firefly
The marine firefly is a very small crustacean less than an inch in length. It lives near the shallow waters of Japan. During the mating season, the male will spray bright points of light to show the females his whereabouts. It was also used by soldiers during World War II to highlight messages at night.
# 2 The animal that glows in the dark: Tomopteris
Tomopteris is a genus of plankton (small floating marine organisms found in all oceans of the world). Although many types of plankton emit light, it is the only plankton that produces the rare yellow bioluminescent glow. From observation, Tomopteris appears to release glowing particles from the sinewy protrusions of its body (they look like legs), possibly as a means of distracting predators as it makes a safe escape. Typical Tomopteris are just over an inch in size, so they need all the help they can get to dodge predators.
# one Glow-in-the-Dark Animal: Tasmanian Devil
So far, this is one of the few land mammals that could make the list, but its entire discovery was in fact an accident. In December 2020, a zoo technician first discovered that Tasmanian devils (carnivorous marsupial mammals native to the island of Tasmania) can emit a visible glow under the gaze of ultraviolet light. It seems that special proteins in skin and fur absorb energy from sunlight and then emit energy at dusk at a different wavelength that the human eye cannot reach. It has been suggested that this glow may play some role in communication. It also opens up the tempting possibility that more terrestrial mammals can produce or absorb light than we currently know. Flying squirrels and gingerbreads have also been observed to glow in ultraviolet light.
List of animals that glow in the dark
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