Invertebrates

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From the giant squid to microscopic squid babies, squids are beautiful and fascinating. As cephalopods, the same family as octopuses and cuttlefish, they have no bones, and swim head-first through the water with their...
Since summer 2013, starfish along both coasts of the United States have been...
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Tiny plant-like organisms called zooxanthellae live in the tissues of many...
I have been at the Smithsonian’s National Museum of Natural History since 1966...

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Discovering new species is an exciting quest, right? Well, some parts are—but after you find a cool-looking organism that you think is a new species, there's a lot more to be done. You have to confirm that it's new, write a...
How does a coral spend its day? Most of us would say: not doing much. To the...
The blue crab ( Callinectes sapidus ) is one of the most important...

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Jellyfish and comb jellies are gelatinous animals that drift through the ocean's water column around the world. They are...

The Ocean Blog

Isopods (small, shrimp-like animals) like this one ( Gnathia aureusmaculosa ) are the mosquitoes of the sea, sucking the blood of fish while they sleep. Find out more in " No Fouling Around " from...
Giant squid live up to their name: the largest giant squid ever recorded by scientists was almost 43 feet (13 meters) long, and may have weighed nearly a ton. You’d think such a huge animal would be...
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...
This ctenophore (a stingless jellyfish-like animal) is native to the east coast of North and South America. In 1982, it was discovered in the Black Sea, where it was transported by ballast water . It...
A chambered nautilus shell.
Weighing 600 pounds (around 272kg) and having a 30 foot (around 9 meters) arm span, the largest recorded giant pacific octopus was truly enormous. Giant pacific octopuses are powerful predators that...
Since late April, the world has watched a devastating oil spill from a BP drilling rig spread throughout the Gulf of Mexico and become one of the worst environmental disasters in the history of the...
This jelly’s red color provides camouflage in the deep ocean. Red light rarely reaches those depths, and most deep-sea animals have lost the ability to see red. The long, complex tentacles of this...
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 .
Giant anemone. More about mangrove ecosystems can be found in the Mangroves section .
Using a deep-diving ROV, the crew aboard Oceana’s research vessel Ranger were surprised to discover large colonies of deep-sea white coral in the Western Mediterranean Sea in July 2010. Most of the...
"Inside the Open Ocean: Blue Water Diving" produced by Woods Hole Oceanographic Institution (WHOI) , describes a specialized diving technique that lets biologists study the ocean's most fragile...
"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,...
Small amphipods, the blue bug-like creatures, can be seen here catching a ride on this enormous sea spider as it makes its way across the bottom. Many Antarctic creatures, like the dinner-plate-sized...
Sea butterflies (also called pteropods) are sea snails aptly named: they are shelled marine snails, each with a foot like a wing, that swim in the water column like butterflies. This one, Atlanta...
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