More Defenses

One of the first signs of a sick coral reef is seaweed creeping across the corals, stealing their precious sunny real estate. Healthy corals, however, aren't completely hopeless: in some reefs, small...
An octopus shoots ink in defense as it swims away from a scuba diver.
When most people think of catfish, they think of a freshwater fish. But the striped eel catfish ( Plotosus lineatus ) is found in marine systems including coral reefs, estuaries, tide pools and other...
The ROV Hyper Dolphin caught this deep-sea jelly (Atolla wyvillei) on film east of Izu-Oshina Island, Japan. When attacked, it uses bioluminescence to "scream" for help—an amazing light show known as...
This bait ball shows how small fish can react when larger predators are near by gathering tightly together in a ball-like formation that exposes the least number of fish. Fish species found in the...
This nudibranch has a few tricks up its sleeve: it steals jellyfish tentacles to use as weapons again its own enemies. How does it do this? Many fleshy, tentacle-like growths, called cerata (singular...
Nudibranchs are a kind of sea slug, and their 3000 species are found from the poles to the tropics in both shallow and deep water. Though they often only reach two centimeters in length, they are...
When hoping to discover a pearl, looking inside one of the oysters you slurp may not be the best plan. Food oysters in the family Ostreidae are able to produce pearls, however these tend to be small...
Not all slugs (snails without shells) are slimy brown pests found in your backyard garden. In the ocean they come in a huge variety of colors — some match the background and are hard to spot, but...
Beluga whales are naturally vocal animals. They are often called “ canaries of the sea ” thanks to their wide repertoire of sounds such as whistles, squeals, moos, chirps, and clicks. Some...
It's a pygmy seahorse ( Hippocampus bargibanti ), found in Indonesia's biodiverse Coral Triangle and one of the smallest seahorse species in the world! They can change colors like a chameleon to...
The lion’s mane jellyfish ( Cyanea capillata ) is the largest among the jelly species, with the largest known specimen stretching across 120 feet (36.5 meters) from its top to the bottom of its...
This crab ( Neolithodes sp. ) was collected on a NOAA/MAR-ECO cruise to the Mid-Atlantic Ridge in the summer of 2009. Its red color provides camouflage and protection from predators. Red wavelengths...
The blue-lined octopus may be small, growing to at most 15 cm, but it can be deadly: its venom can cause breathing failure in humans as well as other animals. Turtles can accidentally consume the...
by Fox Meyer Squids, octopuses, and cuttlefishes are among the few animals in the world that can change the color of their skin in the blink of an eye. These cephalopods —a group of mollusks with...
Is that fruit swimming in the ocean? Well it may look like fruit, but it's actually a pineapplefish ( Cleidopus gloriamaris ). Like the hard outer part of a pineapple, this fish also has an outer...
You may have seen the sparkle of fireflies on a summer’s night. The fireflies produce light through a chemical reaction in their glowing abdomens, a process known as bioluminescence. But did you know...
These beautiful mandarinfish ( Synchiropus splendidus ) are covered in bright blue, red, yellow and orange waves. What they lack, however, are traditional fish scales. Instead of your typical fish...
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