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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 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...
Dr. Clyde Roper, squid expert, explains how he developed a passionate interest in the giant squid ( Architeuthis dux) in this excerpt of "Eyeball to Eyeball," an episode of Errol Morris' First Person...
You may have seen the sparkle of fireflies on a summer’s night. The fireflies produce light through a chemical reaction in their glowing abdomens, a process known as bioluminescence. But did you know...
This male dancing fiddler crab ( Uca terpsichores ) has built a sand “hood” at the entrance to his burrow, which he hopes will attract females to his humble abode—as if that big beautiful claw of his...
A longshoreman stands in front of a large pile of oyster shells on waterfront pier in Atlantic City in 1910. Back then, oysters were incredibly abundant. In the late 1800s, fishermen pulled in 10...
This close-up photo of a right whale's head shows dozens of hitchhikers—tiny crustaceans known as whale lice, or cyamid amphipods. They live on the rough patches of skin (known as callosities) on...
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...
Giant squid have the largest eye in the animal kingdom. At up to 10 inches in diameter, people often describe it as the size of a dinner plate -- or, in other words, as big as a human head. Here,...
Several species of amphipod like this one, Gammarus wilkitzkii , live permanently within Arctic sea ice . These animals are endemic, meaning they only live here. They acclimate to a wide range of...
In this video Smithsonian research zoologist Dr. Martha Nizinski takes viewers with her as she searches for crustaceans in the deep sea . She's particularly interested in finding squat lobsters ,...
This specimen of the deep-sea coral Desmophyllum dianthus shows the visible bands that help marine scientists learn how ocean conditions changed over time. By looking at the thickness of each band,...
Hyperiid amphipods are small crustaceans related to sand fleas and distantly related to shrimp. They range in size from very tiny to more than 7 inches long, and are found at all depths of the ocean...
“This image was captured during an evening dive in water where the largest migration on Earth occurs nightly," said Nature's Best Photographer Joshua Lambus. The migration he speaks of is the diel...
Atolla tenella , a midwater scyphomedusa , as seen under a microscope. View the “Under Arctic Ice” photo essay to learn more.
The sea hare gets its common name from its equivalent of nose and tongue—external sensory organs for smell and taste called rhinophores—which look like bunny ears. The sea hare, however, doesn't hop...
A specimen from the Smithsonian’s squid collection and videos of a mystery squid helped scientists identify a new family of deep sea squid—the Magnapinnidae, known as the bigfin squids. More about...
Home is where the hull is: Since the dawn of seafaring, humankind has had to deal with pesky creatures, such as barnacles, that “foul” ship hulls and boat propellers like this one. Find out more in...
A male mudflat fiddler crab ( Uca rapax ) waves its huge claw to impress females and threaten competitors. Only the males have the large claw. When the tide is high, fiddler crabs retreat to their...
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