Invertebrates

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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 closures, or...
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The ocean is home to a phenomenal diversity of marine organisms. They have...
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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...

LATEST CATCH

How many animals swim in the sea? It's not easy to count them all. To get a feel for the ocean's diversity, scientists, such as those involved in the Census of Marine Life , sail out on research cruises to collect and count as...
With a scientific name that means "the vampire squid from hell," you'd...
Zombie worms ( Osedax roseus ) eat away at the bones of a dead whale that...

DIVE DEEPER

Nudibranchs are a kind of sea slug, and their 3000 species are found from the poles to the tropics in both shallow and deep...
Squids come in a wide range of sizes but despite differences in size and shape, all work basically the same way inside. More about the giant squid can be found in the Giant Squid section .
The loco ( Concholepas concholepas , often called the Chilean abalone, although it isn’t actually an abalone) is found along the entire coast of Chile.
The larger of two giant squids on display in the Smithsonian's Sant Ocean Hall , this female was caught in a fisherman's net off the coast of Spain in 2005. It was probably 2-3 years old and, when...
An isopod retrieved from an Autonomous Reef Monitoring Structure (or ARMS) off the coast of Florida.
Zombie worms ( Osedax roseus ) eat away at the bones of a dead whale that has fallen to the seafloor in Sagami Bay, Japan. These bizarre worms rely on whale bones for energy and are what scientists...
An octopus shoots ink in defense as it swims away from a scuba diver.
Last week, Smithsonian research zoologists Dr. Jerry Harasewych and Dr. Martha Nizinski were in Curaçao looking for deep-sea marine gastropods and decapod crustaceans , respectively. I learned they...
"Harlequin shrimp normally live in pairs and their main diet is starfish... It takes a good eye and patience to find this beautiful shrimp, which looks like candy.” -- Nature's Best photographer,...
Scypholanceola aestiva looks like an armored alien of the deep. It doesn’t have compound eyes like other hyperiids, but instead sees variations in light using reflective cups embedded in the...
Welcome to Citizens of the Sea , a new blog series where ocean life comes to life. Our book by the same name came out in September, but no sooner had it gone off to the printer than new ocean stories...
Tectitethya crypta (formerly known as Cryptotheca crypta ) is a large, shallow-water sponge found in the Caribbean. It was first studied for medical purposes in the 1950s when few scientists or...
Acorn barnacles ( Balanus crenatus ) make a home on the carapace of an edible crab ( Cancer pagurus ). Much of the Baltic suffers from eutrophication that leads to oxygen depletion. The algae blooms...
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 "...
With seven pairs of legs, nine eyes, a tail with light-sensing organs and shells the shape of flying saucers, horseshoe crabs, like this species from Thailand ( Tachypleus tridentatus ) look like...
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 .
If there had been room to stand up, there would have been a standing ovation. As it was, the five of us on the submersible Curasub clapped and cheered when the first three deep-reef ARMS (Autonomous...
Ochre seastars ( Pisaster ochraceus ) feed on invertebrates, such as coral and shellfish, like the mussels pictured here. The starfish forces open the shell with suction disks on the underside of its...
Tiny plant-like organisms called zooxanthellae live in the tissues of many animals, including some corals , anemones, and jellyfish , sponges, flatworms, mollusks and foraminifera . These microscopic...
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