Most deep-sea creatures look like something from the underworld. Their oversized eyes, bizarre bodies, and unusual movements ...

From starfish and sea slugs to jellyfish and sponges, the ocean's invertebrates are some of the most ancient and diverse ...

Called by-the-wind sailor or velella velella, here's what to know about the small, glassy jellyfish-like critters washing up ...

SeaWorld San Diego announced Wednesday its newest exhibit, Jewels of the Sea: A Jellyfish Experience, will officially open on ...

This story appears in the October 2018 issue of National Geographic magazine. Moon jellies, which are found in shallow bays around the world, look like small, not entirely friendly ghosts.

The ‘David Packard’ is named for the Silicon Valley pioneer who donated more than $1 billion to ocean research.

"By-the-Wind Sailors" wash ashore in Ventura, causing a colorful spectacle but prompting warnings against touching.

They roam ocean currents, usually in pelagic zones, feeding on sea jellies and other small critters. Fowler, a marine ecologist, said ocean sunfish are rare off Western Australia but can be ...

Portuguese man o’ war have been spotted on Spanish beaches, forcing the temporary closure of some popular shorelines last year ...