Crabs drugged with Prozac are behaving badly, or at least in risky ways, new research finds. The researchers weren't interested in finding the right dose of the antidepressant (generic name fluoxetine hydrochloride) to treat anxious or depressed crabs. Rather they were interested in seeing how the drug, which makes its...

Some male animals are known for busting a move in elaborate mating dances to woo prospective mates. But some crab males perform a special dance for the males they've just defeated in combat, to discourage them from coming back for more, according to a new study. Scientists had previously observed...

Scientists have discovered a new species of hobbit shrimp that shares more than a feature or two with the protagonist of J.R.R. Tolkien's 1937 children's fantasy novel. The diminutive size and eight hairy limbs of the critter, dubbed Odontonia bagginsi, recall Bilbo Baggins, the reluctant halfling hero who found a...

Shrimp-like creature (Image credit: Copyright Royal Ontario Museum)The ancient creature Waptia fieldensis had a shrimp-like tail. [Read more about the shrimp-like Cambrian critter] Mustache-like antenna (Image credit: Marianne Collins/Copyright Royal Ontario Museum)An illustration showing W. fieldensis's rounded, paddle-like appendages and its spiny upper legs. It also had a mustache-shaped pair...

An aggressive breed of green crab is invading Maine's waters. The crabs (Carcinus maenas) threaten blue mussels, soft-shell clams and the eelgrass beds off the state's rocky coast. The crustaceans are also just plain nasty: Researchers who work with the crabs say that instead of hiding from threats, the critters...

SeaWorld put out a stunning video last week of a Japanese spider crab (Macrocheira kaempferi) cracking open its outer shell and seeming to clamber out of itself. The molting process captured in the video out of San Diego is natural. As NOAA Fisheries explains on its website, crabs cannot grow...

An international team of astronauts has discovered a new species of blind, colorless, cave-dwelling crustacean — and they didn't even have to leave Earth to find it. The fingernail-size crustacean, named Alpioniscus sideralis after the Latin word for stellar, was discovered scuttling about a pitch-black pool in the Sa Grutta...

Giant eyes (Image credit: Oksana Vernygora/University of Alberta)Here is an illustration of Callichimaera perplexa, quite possibly the strangest looking crab that ever lived. [Read more about the strange crab] Crabby fossil (Image credit: Daniel Ocampo R., Vencejo Films)Yale paleontologist Javier Luque found C. perplexa in Colombia in 2005. Since then,...

An ancient crab that lived during the dinosaur age was so strange, paleontologists are calling it the platypus of the crab world. This newly discovered critter — named Callichimaera perplexa, which means perplexing beautiful chimera — had a hodgepodge of body parts. That name references the mythical chimera from Greek...

As if preparing for battle, some shrimplike creatures suit up in aluminum armor to survive the ravages of the deepest part of the oceans, a new study finds. Amphipods are little crustaceans found in most waters on Earth. One species, Hirondellea gigas, dwells at the bottom of the sea —...

It's no mystery why natural selection favors bluish-green lobsters: Individuals that live inconspicuously on the seafloor are more likely to survive and pass their genes on to offspring. Lobsters live in rocky or muddy areas, said Anita Kim, an assistant scientist at the New England Aquarium in Boston. They rely...

Humans have pumped about 2 trillion tons (1.8 trillion metric tons) of carbon dioxide (CO2) into the atmosphere since the start of the Industrial Revolution, and the ocean has absorbed about 25% of it. This glut of greenhouse gases not only warms the ocean (contributing to more-frequent heat waves and...

Coconut crabs, Earth's biggest land crabs, are internet famous from images in which they dwarf trash bins and tear birds limb from limb. But when these crabs aren't devouring seabirds, they're chatting to each other in vibrating clicks, and scientists recently discovered that the crabs' weird clicking calls are unexpectedly...

About 518 million years ago, a fierce shrimp-like creature didn't brandish just one knife, it flashed more than 800 of them; each of its 54 legs had up to 15 dagger-like spines on it, a new study finds. The name of this newly discovered Cambrian period scavenger, Xiaocaris luoi, literally...

A perfect home is hard to find, and some mantis shrimp called smashers for their clublike arm work hard to locate one that's just right. If the home already has an owner, the invader will fight fiercely to evict it. To find out how aggressively this tiny crustacean will fight...