More Defenses

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...
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...
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...
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...
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...
This summer, many of you have likely enjoyed feasting on crabs, be they blue, stone, or Dungeness, and a special treat will have been the big, easy morsels of claw meat. The size of this muscle is...
An octopus shoots ink in defense as it swims away from a scuba diver.
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...
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...
Two bright orange anemonefish ( Amphiprion ocellaris ) poke their heads between anemone tentacles. Anemonefish are able to swim amongst the stinging tentacles without getting stung — but no one knows...
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...
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...
Most scuba divers scour coral reefs looking for colorful fish, natural beauty, and maybe even the perfect underwater photo . Shirley Pomponi , a biologist at Florida Atlantic University's Harbor...
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...
Stinging cells (nematocysts) line the tentacles of this moon jelly ( Aurelia aurita ). Upon contact with prey or a predator, a venom-laden harpoon shoots out to stun or kill. Read more about...
Anemone porcelain crabs may look delicate but they have their own sort of armor: a hard exoskeleton. They live under rocks, sponges, groups of feather stars, and even in giant anemones where they can...
A humboldt squid ( Dosidicus gigas )—also known as the jumbo squid—releases a cloud of ink at night in Mexico's Sea of Cortez. These large, carnivorous squids can reach more than 5 feet in length and...
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...
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