Invertebrates

Animals without backbones make up a huge percentage of the ocean’s biodiversity. They aren’t just small (like pteropods) or squishy (like jellyfish); the giant squid and corals that build huge reefs are also invertebrates.

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Marine parasites may be small in size, but they can be present in very high numbers and put together can weigh even more than all the top predators in an estuary or bay ecosystem!...
During the summer of 1998, scientists at the Virginia Institute of Marine...
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The blanket octopus can rip a poisonous tentacle from a Portuguese man-o-war...
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Hyperiid amphipods are small crustaceans related to sand fleas and distantly...

LATEST CATCH

Census of Marine Life researchers discovered this unusual transparent sea cucumber ( Enypniastes sp.) in the Gulf of Mexico at 2,750 meters depth. It creeps forward on its tentacles pretty slowly, at around 2 centimeters per...
Smaller than the head of a pin, this arrow squid (Doryteuthis plei ) embryo...
What are corals? Corals themselves are animals. But tropical reef-building...

DIVE DEEPER

Jellyfish and comb jellies are gelatinous animals that drift through the ocean's water column around the world. They are...
Ultraviolet light illuminates the growth rings in a cross-section of a 44-year-old deep-sea coral ( Primnoa resedaeformis ) collected off the coast of Newfoundland at about 1,300 feet (400 meters)...
This nudibranch has a few tricks up its sleeve: it steals jellyfish tentacles to use as weapons against its own enemies. How does it do this? Many fleshy, tentacle-like growths, called cerata (...
Like this ctenophore ( Aulococtena acuminata ), many animals that live in the midwater zone are red—making them almost invisible in the dim blue light that filters down from the sea surface. This...
Jellyfish and comb jellies are gelatinous animals that drift through the ocean's water column around the world. They are both beautiful—the jellyfish with their pulsating bells and long, trailing...
In recent years, blooms of jellyfish, such as these moon jellies ( Aurita aurita ) in the Chesapeake Bay, have become more common around the world for a number of different reasons . One result of...
As it clings to a red sea fan, a feather star ( Cenometra bella ) gently waves its slender arms—filtering bits of food from the water. Also known as sea lilies, feather stars are related to sea stars...
This sea potato ( Echinocardium cordatum ) looks similar to its root vegetable namesake, but it's a sea urchin! The spines on this urchin are more hair-like than the spikes seen on some more commonly...
Polychaete worms are not your average cringe-inducing, writhing worms. (Okay, maybe some are.) They are fascinating, varied, and a critical part of our ocean. The visual variety among the more than...
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...
In this episode of the Podcast of Life , learn how three fiery, painful stings during an early morning swim in Hawaii changed the life of researcher Angel Yanagihara. Once the young biochemist had...
This rare staurozoan , or stalked jellyfish ( Haliclystus californiensis ) is about 2 centimeters in length and was collected off the coast of California. Unlike the traditional bell-shaped floating...
In 1954 Smithsonian researchers dissected this squid specimen from the stomach of a lancetfish and added it to the Museum’s squid collection. Almost 50 years later, it helped scientists identify a...
Methane gas, trapped deep within the Earth's crust, can slowly leak from cracks in the seafloor known as methane seeps. While we would never consider methane as food, in the deep sea where there is...
A chambered nautilus shell.
Researchers in Moorea use a variety of tools to collect organisms. Some are simple, everyday items like buckets and brushes, and some are…a little stranger. Here, two researchers use a “yabbie pump”...
This is the first photograph of a live giant squid ( Architeuthis ) in its natural habitat. It was taken in 2004 by two Japanese researchers who had suspended a long line from their research vessel...
Dr. Clyde Roper (top left), of the Smithsonian Institution, and scientists from NOAA and the Delaware Museum of Natural History dissect a giant squid specimen donated by NOAA. Everything we know...
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