The world’s oceans are teeming with bioluminescence creatures that glow in the deepest depths and light up even the darkest part of the oceans. Many ocean creatures use bioluminescence to catch prey or protect themselves from predators and use it to attract mates.
Bioluminescence is the production and emission of light by living organisms. It occurs through a chemical reaction that produces light energy within an organism’s body. Bioluminescent creatures have a specific chemical called luciferin, and when it reacts with oxygen, it produces light.
Around 76% of ocean animals are bioluminescent. Most bioluminescence creatures produce blue-green light, a color that transmits best in ocean water. Here are some of the most fascinating bioluminescent marine creatures that you should know about:
Deep-Sea Anglerfish
Use of Bioluminescence: To lure prey and attract mates.
Location: Tropical and temperate seas at depths exceeding 980 feet.
Deep-sea anglerfish are sexually dimorphic and vary in size from 1.2 – 50 inches. Males are ten times smaller than females. They live in the deep ocean at depths of between 980 and 16,400 feet where no light can penetrate and in complete darkness. They have large mouths and sharp teeth that can swallow prey twice their size.
Only female anglerfish exhibit bioluminescence by glowing whitish-blue lures (known as an esca) dangling on their forehead, and use this bioluminescence to attract prey toward them. Recent research found that tiny glowing bacteria, unique to each Deep-Sea Anglerfish species, take root in a special pore on the esca. For more deep-sea creatures with bioluminescent adaptations, check out our in-depth list of creatures thriving with deep-sea adaptations.
Glowing Lanternfish
Use of Bioluminescence: To protect themselves from predators.
Location: All oceans of the world.
Lanternfish are generally 6 inches in size but can range between 0.8 – 12 inches. They live at a depth of 980 and 4,920 feet in the twilight zone of the ocean. However, as nighttime approaches, they rise to the epipelagic zone (33 and 328 ft) following the vertical migration of their prey, zooplankton, in addition to avoiding predators. They are slim, with a large round head and large eyes.
Lanternfish have light-producing organs on their bellies called photophores, through which they exhibit bioluminescence by glowing blue to confuse predators who attack from below.
Hawaiian Bobtail Squid
Use of Bioluminescence: To protect themselves from predators.
Location: Pacific Ocean, especially coastal waters off Hawaii.
The Hawaiian Bobtail Squid has a mantle size of up to 1.2 inches. It lives in the shallow coastal waters off the Hawaiian and Midway islands in sandy and muddy habitats associated with seagrass beds. They have big brains and large fins compared to their body size.
Hawaiian Bobtail Squid are mottled and can change their color with the help of special organs called chromatophores. They have bioluminescence bacteria on the underside of their body. They use counter-illumination to glow the same shade of light as the water above, allowing the squid to hide from the predators who attack from below.
Scaly Dragonfish
Use of Bioluminescence: To attract prey, confuse predators, and identify other individuals.
Location: All oceans of the world.
The Scaly Dragonfish can grow up to 13 inches long. They live at a depth of 650–4,900 feet but migrate to the epipelagic zone at night to feed on fish. They have large eyes and a big mouth with sharp, curving teeth.
Scaly Dragonfish have photophores, specialized organs that produce light, scattered across their body, especially on its underside. It also has a long rod with white glowing tips at its chin. They employ this bioluminescence to attract their prey.
Comb Jelly
Use of Bioluminescence: Possibly to protect themselves or to communicate.
Location: All of the world’s oceans.
The Comb jelly varies in size depending on the species, but they can reach a maximum length of 5 inches. They live at a variety of depths from surface waters down to 23,000 feet. They have oval-shaped, transparent bodies with eight rows of comb-like plates with infused cilia on them.
Comb jellyfish have protocytes under their cilia, and when they move, the comb-like plates diffract light to produce a shimmering bluish rainbow effect. Some species, like Bathyctena chuni, can produce bioluminescent ink when disturbed. The function of bioluminescence is not well understood, but it may be related to communication or defense.
Firefly Squid
Use of Bioluminescence: To possibly camouflage themselves from predators, to communicate, and to attract their prey.
Location: Deep waters of the Western Pacific.
The Firefly Squid is small, measuring 3 inches long. They live at depths of 700-13,000 feet but move closer to the surface in coastal Japan during the Spring and Summer months to mate. They have eight arms and two tentacles, each with a sucker and hooks.
Firefly Squid have three types of photophores that vary in size depending on their body position. These photophores produce bioluminescence and make firefly squid look like they have neon lights all over their body. The function of bioluminescence is not well understood in this species, but it may be related to camouflaging themselves from predators, for communication, and to attract their prey.
Deep Sea Shrimps
Use of Bioluminescence: To confuse and distract predators.
Habitat: Deep waters of the world’s tropical seas.
Deep Sea Shrimp are small and range in size from 2.2 – 4 inches long. They live at depths of 980 – 10,800 feet. They are bright red with ten legs and two sets of antennae.
Deep Sea Shrimp exhibit bioluminescence in two ways. They spew luciferin from its mouth which reacts with oxygen in the water to produce a bright blue light to confuse or distract potential predators. It also has photophores along its body that emit light.
Green Bomber Worm
Use of Bioluminescence: To distract predators.
Habitat: Pacific Ocean between 3 – 1,475 feet above the ocean floor.
Green Bomber Worms are small in size, measuring about 1.1 inches long and a 1/4 inch wide. They are holopelagic and live in the water column between 3 – 1,475 feet above the ocean floor. They have transparent bodies lined with 30 bristles which they use to swim through the water.
These glowing worms discard their bioluminescent gills to distract predators. These glowing gills are circular and flash for a few seconds, allowing the worm to escape.
Ocean Insights: Hear From Our Experts
By Dr. Rabiah Ryklief
Principal Scientist and Lecturer of Marine Science, with a PhD in Zoology
Deep-Sea Anglerfishes have one of the most bizarre mating strategies in the animal kingdom. Males essentially become permanent parasites on the much larger females! These tiny, sperm-producing hitchhikers fuse with the female, sharing blood and relying entirely on her for survival. This extreme strategy makes perfect sense in the vast, abyssal depths of the ocean where encounters are rare – a guaranteed chance to reproduce whenever you find a mate! It's a fascinating example of how evolution adapts to overcome environmental challenges.
FAQs
Why are some animals bioluminescent?
Some species of fish, like Anglerfish, use bioluminescence to lure prey. Others, like Squid, use it defensively with sudden flashes to confuse predators. In the deep sea, Lanternfish use bioluminescence to communicate and possibly to identify their other Lanternfish.
How common is bioluminescence?
Bioluminescence is surprisingly common, especially in the ocean. Estimates suggest around 75% of deep-sea animals possess this ability. It’s less frequent on land, where fireflies and some mushrooms are notable examples.
Can animals turn off bioluminescence?
Many deep-sea creatures can turn their light on and off. Bioluminescence is a complex biochemical process, and different species have evolved various mechanisms for controlling their glow.
What is the most common color emitted by bioluminescent creatures?
Most bioluminescence organism produces blue-green light, a color that transmits best in ocean water. Other than that, yellow and red are the rear lights emitted by a few creatures.
How is bioluminescence triggered?
A molecule called luciferin reacts with oxygen, like fuel. An enzyme named luciferase acts like a spark plug, and together they create light. Some creatures even have a simpler system with a single light-emitting molecule.
