Atlantic horseshoe crab (Polyphemus occidentalis) illustration from Zoology of New york (1842 - 1844) by James Ellsworth De Kay (1792-1851).

The Horseshoe Crab: Same as It Ever Was?

The seemingly static appearance of these ancient-looking arthropods presents a challenge for scientists who want to study their evolutionary history.
Many cassiopea xamachana, upside down jellyfish

Upside-Down Jellyfish and the Mucus of Death

You could get stung by a jellyfish even when there don't seem to be any around. Meet Cassiopea xamachana and its "stinging water" weirdness.
An octopus

Stuck in the Midden with You

A midden is, among other things, a refuse site outside an octopus' home. (Release the Køkkenmødding!)
Pendant in the Form of Neptune and a Sea Monster

The Lumpy Pearls That Enchanted the Medicis

There’s a specific term for these irregular pearls: “baroque,” from the Portuguese barroco.
A shark being cleaned by smaller fish

Where the Small Fish Clean the Bigger Ones

A "cleaner station" is a sort of undersea business, a place where large, often predatory, fish go to have parasites removed.
A new lava stream cascades into the ocean at the former lava delta site in Hawai‘i Volcanoes National Park.

Volcanic Ecosystems in the Deep Ocean

Undersea volcanoes, like Hawaii's Kīlauea, foster diverse ecosystems in an environment far from sunlight—and as acidic as lemon juice.
Sand Octopus (Octopus kaurna)

How to Make Quicksand Like an Octopus

When it comes to camouflage, the sand octopus has some truly amazing techniques.
Seattle sea wall

A New Way to Protect the Coast

Living shorelines provide erosion control while providing shoreline habitat and maintaining coastal processes.
Electric eel

5 Shocking Facts about Electric Eels

First things first: eels are fish.
Orca Juvenile

Starving Killer Whales Are Losing Most of Their Babies

The southern resident killer whales of the northeast Pacific are in trouble. As habitats and food dwindle, they increasingly miscarry and lose their babies.