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The ocean is home to a phenomenal diversity of marine organisms. They have evolved to inhabit warm waters near the equator and the icy waters of the Earth’s poles. Marine life takes advantage of...
This summer, many of you have likely enjoyed feasting on crabs, be they blue,...
Zombie worms don’t crave brains: instead they seek bones. The 1 to 3 inch (2 to...
Marine parasites may be small in size, but they can be present in very high...

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The blue crab ( Callinectes sapidus ) is one of the most important commercial species in the United States, especially in the Chesapeake Bay region on the Mid-Atlantic coast. Its populations are affected by local water quality,...
Like this ctenophore ( Aulococtena acuminata ), many animals that live in...
Sponges are animals that eat tiny food particles as they pump water through...

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Sample the surprising diversity of deep-sea corals. See some of the ways they differ in color, shape, and size. Explore more...

The Ocean Blog

Ultraviolet light illuminates the growth rings in a cross-section of a 44-year-old deep-sea coral ( Primnoa resedaeformis ) collected off the coast of Newfoundland at about 1,300 feet (400 meters)...
Named for the radiant blue color on its back and sides, the blue shark ( Prionace glauca ) traverses the world’s temperate and tropical seas. Known for traveling great distances and being a swift...
This tiny, shrimplike creature is no more than 2.5 centimeters (1 inch) long, but it’s as ferocious as a shark. Its giant eyes spot prey. Huge claws grab the prey, and a tiny mouth rips it to shreds...
What reef animal comes in a rainbow of crazy colors, can throw out its stomach to immobilize predators, then creep away and regrow a brand-new stomach? It’s the sea cucumber, prized as a gastronomic...
A mass of white muscle the size of a softball surrounds the dark brown beak of a giant squid. Learn more about this animal's oversized anatomy in our Giant Squid section .
Like it or not, giant squids are related to snails, clams, and even slugs. They are all mollusks and have soft, fleshy bodies. More can be found in the Giant Squid section .
Sea jellies such as this one in the genus Benthocodon are commonly seen on or near the seafloor in the Monterey Canyon off central California. Some jellies in this genus feed on animals that live in...
Brachiopods are an ancient group of organisms, at least 600 millions years old. They might just look like clams, but they are not even closely related. Instead of being horizontally symmetrical along...
These brittlestars ( Ophiothela mirabilis ) are not where they belong. These animals, usually found in the Pacific Ocean, were first spotted in the Atlantic Ocean off the coast of Brazil in 2000. And...
This pair of sea butterflies ( Limacina helicina ) flutter not far from the ocean's surface in the Arctic. Sea butterflies are a type of sea snail, but instead of dragging themselves around the...
Some of the most otherworldly animals—like those straight from a science fiction story—can be seen in the open ocean at night. By drifting in the blackwater in a scuba suit just under the surface,...
Bottom trawl treasures from the shallow Chukchi Seafloor near the Canada Basin: sea stars , brittle stars , clams, some snails and crabs. View the “Under Arctic Ice ” photo essay to learn more.
What are corals? Corals themselves are animals. But tropical reef-building corals have tiny plant-like organisms living in their tissue. The corals couldn’t survive without these microscopic algae–...
Fitting nine of anything on two fingers is impressive. These mollusks and echinoderms are a teeny-tiny sample of the ocean's biodiversity. The Census of Marine Life estimates that there are at least...
Sea stars ( Odontaster validus ) and sea urchins ( Sterechinus neumayeri ) spread over an algae-covered seafloor off the coast of Antarctica. These two species are often found living in association...
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...
The open ocean is surprisingly barren to the naked eye. Every now and again you will encounter a school of fish and their attendant predators, but most of the life that you find is gathered around...
For nearly 35 years, National Geographic photojournalist Brian Skerry has been immersing himself in the big blue to get the perfect underwater photograph. He admits that there will never will be a "...
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