Meet Cystisoma, the 7-inch crustacean with eyes for a head

View a gallery of animals found on abyssal plains, hydrothermal vents, seamounts, and other deep-sea habitats.

Meet siphonophores, breathtaking jellyfish-like organisms

Siphonophores are colonial jelly-like creatures made up of specialized segments that work together as one. They're fairly unknown despite being a significant sea predator. Sink into their strange beauty with this video.

Some organisms are composed of a single cell visible to the naked eye

By incorporating tough, cellulose-rich cell walls, rapid movement of molecules via cytoplasmic streaming, and other biological techniques, some unicellular organisms can bypass the physical limitations that restrict the size of cells. Organisms such as the Stentor coeruleus and Acetabularia can be seen without microscopes.

The deep-sea fangtooth has the largest teeth of any marine species relative to body size

From transparent fish to the heaviest worms on the planet, these seven creepy creatures lurk in the deep sea. Learn all about them and the unique traits that help them survive and hunt.

Catfish have taste buds spread across their entire skin, making their whole body function like a tongue that can taste food several feet away.

What we know about the mysterious colossal squid

The colossal squid, the world's largest invertebrate, remained hidden from human discovery until nearly a century ago. Explore the world of the enormous and mysterious creature, including its features, habitat, and scientific significance. You can even plan a visit to the Museum of New Zealand Te Papa Tongarewa and marvel at a real-life display.

Underwater nighttime photos capture the ocean's diversity

Self-taught photographer Steven Kovacs explores Palm Beach's ocean after sunset, capturing tiny sea creatures in deep waters. Over eight years, he's dived into Florida's eastern coast, drifting from 0 to 100 feet, photographing rarely seen larval fish. Lacking formal marine biology training, Kovacs collaborates globally to identify species like cusk eels and the female blanket octopus, known for its revealing membrane. Check out his photos here.

The 10 most amazing deep sea creatures

In this video, researchers from the world-renowned Monterey Bay Aquarium discuss the most fascinating deep sea creatures, and how they developed some of their strangest features.

Divers capture a blanket octopus unveiling her billowing membrane

In a short clip captured during a blackwater night dive in the Lembeh Strait, a blanket octopus unfolds and displays a colorful web multiple times its original size. The aquatic animal’s iridescent body and tentacles glow against the nighttime...

Sea stars are invertebrates—they lack a backbone—and while most exhibit pentametric radial symmetry due to having five arms radiating from a central disk, some can possess more than 40.

Octopuses have taste receptors along their tentacles

Octopus suction cups are filled with modified sensory receptors that can bind with a greater variety of materials and transport a wider array of information, such as flavor, from tactile stimuli. These structures allow the animal to search for food as it crawls the ocean floor.

Owls cannot move their eyes because they lack eyeballs, having instead developed cylinder-like tubes held in place by bones, which provide stability and lock visual focus when hunting prey.

View a gallery of bioluminescent organisms, including jellyfish and mushrooms

Some species produce a quick flash of light, while others glow steadily with an eerie glow, often to seek attention or in response to being disturbed. Snails, worms, fungi, and other organisms highlight that this ability evolved independently, rather than from one common ancestor.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

Evolution doesn't want you to see these animals

Invisibility is an oft-coveted superpower that many creatures throughout the animal kingdom have evolved to mimic through transparent camouflage. This article explores the science of this seemingly magical ability. The two critical ingredients in...

Watch this octopus win every single Escape Room challenge

Octopuses are famously intelligent, solitary creatures covered in hundreds of chemical-sensing suckers. They're also pretty fascinating pets, and even enjoy playing. The crew at OctoLab put one of its more playful mollusks into four different Escape Room-like cages to see how long it would take for it to escape. Watch this video to see the brilliant, if a bit unsettling, methods the animal uses.

Take an interactive dive and see the animals that populate the oceans, from coral near the surface to shrimp-like organisms near the seafloor.

Coral reefs are built by thousands of coral polyps—tiny animals whose mouths both consume food and expel waste.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

A look at how fish less than two inches long climb up 50-foot waterfalls

Shellears use tiny hooks on their front pectoral fins to grip rock like Velcro and take many pauses to recover energy between bursts of movement. Their pectoral girdle—an arch of bone—supports the muscle system needed for the roughly ten-hour climb.

An interactive of the deep sea

Multiple species exhibit convergent evolution by developing crab-like features

Various organisms that appear to be different types of crabs, such as porcelain crabs and coconut crabs, have been shown to belong to distinct decapod lineages whose predecessors resemble shrimp or lobsters. Environmental pressures and other factors have caused these species to develop similar characteristics, which nature has shown are beneficial to survival.

Biofluorescent animals—those that absorb light, such as ultraviolet rays, and re-emit other types of light, such as neon green—include some flying squirrels, scorpions, sea turtles, and platypuses.

Elephant bones likely inspired the cyclops character that appears in 'The Odyssey.'

View a gallery of diatoms—algae surrounded by glass-like shells—captured via microscope.

Massive blooms of microscopic algae called dinoflagellates produce the neon blue light seen in glowing tides.

Stunning up-close photos of animal eyes

The eyes really are the windows to the soul.

Tardigrades average about half a millimeter in size, with rear legs used for grasping

Their physiology and size, which is even smaller in the tun state, allow them to be carried by the wind and latch onto moist surfaces. They have been found in ocean trenches approximately 5 kilometers deep and at altitudes of six kilometers in the Himalayas.

Listen to recordings of different fish species

Scientists have captured and curated this collection of species-specific recordings, helping us gain a deeper understanding of underwater ecosystems. Uncover their sounds, which include a lot of thumps, burps, and grunts.

View a sample of the bioluminescent tree of life

This diagram shows 42 different light-producing organisms, from bacteria and fungi to worms, fish, and crustaceans. It illustrates how the ability to produce light has appeared multiple times across the tree of life, rather than stemming from a single ancestor.

Deep water corals—located throughout the world's ocean basins at depths beyond 200 meters (660 feet)—slowly build small coral gardens in the dark with the help of underwater worms.

The fish can climb walls

Scientists in Brazil captured rare footage of bumblebee catfish climbing waterfalls. How they do it is clear, but why remains a mystery.

Research has found that when their symbiotic algae are not producing oxygen via photosynthesis, corals twirl hairlike structures to circulate water and draw oxygen into their outer tissues.

View colorful flowers that grow on cacti and succulents, popular xerophilic organisms

These dry-loving organisms are able to retain the water they need to grow and reproduce in deserts and arid grasslands through a suite of adaptations, including thick, fleshy stems that store abundant water, a waxy coating that helps prevent water loss, and an uncommon form of photosynthesis that loses less water.

The first appearance of bioluminescence was at least 540 million years ago

After analyzing fossils, genetic data, and statistical methods, scientists believe octocorals were the first organisms to evolve light-producing abilities. As a result of independent evolution across at least 94 species, this phenomenon is connected to a diverse range of behaviors.

Some marine life can survive the extreme pressure of the deep ocean because of specialized molecules that strengthen proteins, enzymes, and cellular membranes.

Acetabularia jalakanyakae is one of the largest known single-celled organisms and is nicknamed the 'mermaid's wineglass' for its umbrella-shaped cap.

Bioluminescence became common in the ocean to support survival in dark environments

Despite seeming like a rare ability in land animals and unseen in plants, bioluminescence has evolved at least 29 times across marine species, indicating its necessity for survival where hiding spots are rare and highlighting how environments provide evolutionary pressure.

Visualizing the 75 largest underwater animals

With so many fish in the sea, which are the largest? This infographic shows fantastic illustrations of the 75 largest sea animals, ranked by average size. The detailed visual is organized in descending order of size, starting with the blue whale,...

View examples of luciferin, the light-emitting molecule behind bioluminescence

Bioluminescent marine organisms rely on various unique luciferins, including Cypridina-type luciferin in seed shrimp and chlorophyll-based dinoflagellate luciferin, to react with oxygen to produce light. These chemicals require unique catalysts to help them bind with oxygen.

Starting with red, colorful objects will appear to lose their colors the deeper they are submerged because water scatters light, reducing the amount available to reflect off objects and be observed.

View the fluorescently stained internal structures of a tardigrade

The photograph won the Olympus Global Life Science Light Microscopy Americas regional award in 2019. Using chemicals from biofluorescent organisms, the image illuminates internal structures with multiple hues in an otherwise mostly colorless organism.

Some corals absorb harmful ultraviolet radiation and re-emit it as visible light, thereby protecting symbiotic algae within their tissues and providing them with energy for photosynthesis.

View a collection of glass sculptures of corals threatened by fishing and deep-sea mining.

View illustrations of bioluminescent functions in marine organisms

Bioluminescence can startle predators, camouflage, lure prey, confuse rivals, or facilitate mate recognition. One tactic—the burglar alarm—involves an organism releasing light to attract a larger predator to its attacker as a means of defense.

As immobile animals, corals and the organisms that live on them have evolved a suite of chemical compounds to prevent disease and ward off predators they cannot outrun.

Studying the circadian clock of a tiny swimming polar creature may help forecast polar ecosystem health

A 2025 study found that Antarctic krill, a food chain staple in the Southern Ocean, have an internal biological clock that helps regulate its swimming patterns and helps the tiny shrimp-like animals adapt to daily and seasonal environmental changes. Better understanding of how the clock and light cues interact may help scientists understand how well the species will respond to pronounced climate change in the polar region.

Light pollution is giving oysters insomnia

Oysters, bivalve mollusks that have light-detecting cells along their skin, can't sleep with all this artificial light. According to a 2022 study, oysters' sleep cycles are disturbed by light dimmer than that provided by the full moon. As with humans, it's possible that these bouts of insomnia could have adverse health effects and contribute to the development of disease over time.

Watch David Attenborough's documentary on bioluminescent creatures, which have been observed using light for hunting, mating, communication, and self-defense, and number in the thousands of species.

Over 1 million fish, marine mammals, and invertebrate species depend on coral reefs for habitats, camouflage, and food.