corals & jellies library

Cnidarians such as jellyfish and corals have stinging cells called nematocysts. When touched they eject barbed threads tipped with poison.

Featured Article: How Coral Reefs Work

How do coral polyps mere millimeters in length form the world's largest living structures? Will these giants of the sea last much longer if the present rate of destruction continues? See more »

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Do jellyfish have the deadliest venom in the world?

As you observe jellyfish twirl underwater, it's difficult not to be mesmerized by their graceful movements. But if their tentacles touch your skin, you'll regret being anywhere near these gelatinous blobs.

How Coral Reefs Work

How do coral polyps mere millimeters in length form the world's largest living structures? Will these giants of the sea last much longer if the present rate of destruction continues?

How Jellyfish Work

Although jellyfish have been around for over 650 million years, they're stil very mysterious. Learn the all about the fascinating jellyfish life cycle.

Coral

Coral, a hard material formed in the sea by colonies of tiny animals called coral polyps.

Jellyfish

Jellyfish, or Medusa (plural: medusae), a water-dwelling animal. It is not a fish but a cnidarian, a spineless, soft-bodied animal.

Jellyfish Behavior

Imagine trying to figure out the details of a jellyfish's life by studying the formless blob that it quickly becomes out of water. Find about about these creatures through jellyfish behavior.

Portuguese Man-of-War

Portuguese Man-of-War, a floating, compound marine animal found in warm regions of all oceans.

Sea Anemone

Sea Anemone, a marine animal closely related to the corals. There are more than 1,000 species of sea anemones.

Cnidaria

Cnidarian, or, Coelenterate, an animal of the phylum Cnidaria, or Coelenterata. The phylum includes the corals, hydras, jellyfish, Portuguese man-of-war, and sea anemones.