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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

These baby olive ridleys ( Lepidochelys olivacea ) will eventually provide a home to crustaceans, mollusks, and other epibionts. That's according to a survey of epibionts living on mature, nesting...
A beroid ctenophore lunges toward prey with its mouth wide open. Beroid comb jellies don't have tentacles to catch prey: instead, they can open their mouths and snap them shut tight to trap prey...
Sea cucumbers might have a cucumber shape, but are definitely animal, not vegetable… or fruit. They belong to the Phylum Echinodermata , which also includes sea urchins, sand dollars, sea stars and...
In this close-up photo, you can actually see the photosynthetic algae, or zooxanthellae, living inside a tiny coral polyp. Look for the brownish-green specks in the colorless polyp. Corals depend on...
Octopi (Or octopuses, both are technically correct) are renowned as one of the smartest animals alive. With no bones except for their sharp beak, they can fit through almost any hole or crevice...
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...
Shown here are several deep-sea coral species: From left to right is an unidentified purple octocoral, a small gold acanthorgorgiid octocoral, and a large colony of pink Corallium secundum . Basket...
Male fiddler crabs, like this one collected on Moorea, wave their enlarged claw as way of signaling to other crabs, especially during mating season. Learn more about the Island of Moorea in the...
There are 47 different species of seahorses and 14 of those were discovered in the last eight years, including Pontoh's pygmy seahorse ( Hippocampus pontohi ), which was officially named in 2008...
Scientists have been studying why populations of crown-of-thorns sea stars ( Acanthaster planci ) have mushroomed in recent decades. Coral reefs can suffer when the sea star's numbers explode because...
This crab ( Neolithodes sp. ) was collected on a NOAA/MAR-ECO cruise to the Mid-Atlantic Ridge in the summer of 2009. Its red color provides camouflage and protection from predators. Red wavelengths...
The sargassum is coated with encrusting organisms, such as bryozoans and hydroids, that use it as a perch to filter feed in the oceanic waters, as well as crustaceans such as thos swimming crab...
In 2012, the long-elusive giant squid was finally filmed live in its natural habitat. The squid was found by placing glowing lures outside of a submersible to mimic jellyfish, which typically...
Giant anemone. More about mangrove ecosystems can be found in the Mangroves section .
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...
Seahorses range in size—from as small as a pine nut to as large as a banana. The largest seahorse species (pictured here) is Hippocampus abdominalis , or the big-bellied seahorse, which can reach...
This purple urchin Paleopneustes cristatus is seldom seen by itself, and can be found in groups of hundreds. Dr. Dave Pawson , a senior scientist at NMNH who studies deep-sea echinoderms, is testing...
Staghorn (seen here) and elkhorn corals are listed as Threatened under the Endangered Species Act. They are the only coral species currently listed, but 66 other coral species have been proposed for...
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