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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...
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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...
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Marine parasites may be small in size, but they can be present in very high...

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Many sperm whales stranded on beaches or caught by whalers exhibit telltale circular scars like these. Only one thing could have made them: the strong suckers that line the giant squid’s eight arms and two long feeding tentacles...
Two bright orange anemonefish ( Amphiprion ocellaris ) poke their heads...
White abalones are slow-moving, algae-eating mollusks. Rapid overharvesting...

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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 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...
All over the world, people have been witnessing gigantic blooms of tens of thousands of jellyfish where once there were only a few. Fishers find them clogging their nets and costing them dearly. In...
The island of Moorea is a natural laboratory for scientists on a quest to catalog every life form big enough to pick up with tweezers. Head out into the field and watch as researchers use cutting-...
The over 1,000 species of ribbon worms ( Nemertea ) are mostly found in marine environments (like the Hubrechtia found in a mud flat, in the photo). These worms have both a mouth and an anus (unlike...
Sunset? Time to glow! A biological clock triggers bioluminescence in the dinoflagellate Pyrocystis fusiformis . At dusk, cells produce the chemicals responsible for its light. Hear from marine...
This tan urchin, Conolampas sigsbei , is one of only two known deep-sea urchins that cover their tops with small rocks and shells. Many shallow species cover themselves for reasons that have been...
Depending on whom you talk to, jellyfish are either fascinating, a nuisance, a toxic menace, or some combination of the above. Jellyfish plop into the media spotlight when their presence causes beach...
There aren't any mummies or zombies buried under the seafloor: instead the ocean has its own terror from below, the bobbit worm ( Eunice aphroditois ). A couple inches wide and up to ten feet long,...
This venomous box jelly ( Chiropsalmus quadrumanus ) was collected off the coast of South Carolina. The specimen now resides in the Smithsonian’s marine collection . It's venomous sting can be lethal...
Hermit crabs, like this one collected in Moorea, usually protect their soft, vulnerable abdomens from predators by reusing empty snail shells. They are picky home owners and they will trade shells...
This snapping shrimp female ( Synalpheus regalis ) is the queen of her colony which means she is the only female to have babies. She stores her clutch of eggs under her abdomen until they hatch -...
The feathery strands at the back of this nudibranch’s ( Chromodoris willani ) body are no mere adornment: they’re its gills! Nudibranchs, shell-less snails or sea slugs, are named for these tufted...
Deep sea animals have to live in a very cold, dark, and high-pressure environment where they can't see a thing! To survive there, they've evolved some very strange adapations. Some make their own...
The veined octopus ( Amphioctopus marginatus ), also known as the coconut octopus, has a skill beyond other cephalopods: it hides under animal and coconut shells, dragging them along the seafloor for...
These corals from the Smithsonian collections are Stephanocyathus (A.) spiniger , a solitary, deep-water stony coral species. Around 74% of all deep-water corals are solitary, living as individual...
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 .
Shellfish from the Chesapeake Bay are prized by seafood lovers. But the Bay's ecosystem and fisheries are threatened by human disturbances, including the introduction of non-native species. Non-...
Smithsonian squid expert Dr. Clyde Roper collaborated with National Geographic to attach this Crittercam to the head of a sperm whale, hoping to get footage of the whale’s favorite prey—giant squid...
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