Photograph by Joel Sartore, National Geographic Photo Ark
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A blue crab photographed in Myrtle Grove, Louisiana
Photograph by Joel Sartore, National Geographic Photo Ark

The blue crab is so named because of its sapphire-tinted claws. Its shell, or carapace, is actually a mottled brownish color, and mature females have red highlights on the tips of their pincers.

As Food

Prized by humans for their sweet, tender meat, these wide-ranging, ten-legged crustaceans are among the most heavily harvested creatures on the planet. Their scientific name, Callinectes sapidus, means "savory beautiful swimmer."

Habitat and Range

Blue crabs are found in brackish coastal lagoons and estuaries from Nova Scotia, through the Gulf of Mexico, and as far south as Uruguay. Close relatives of the shrimp and lobster, these bottom-dwelling omnivores have a prickly disposition and are quick to use their sharp front pincers. Large males can reach 9 inches in shell width.


They feed on almost anything they can get hold of, including mussels, snails, fish, plants, and even carrion and smaller blue crabs. They are also excellent swimmers, with specially adapted hind appendages shaped like paddles.

Population Declines

Blue crabs are extremely sensitive to environmental and habitat changes, and many populations, particularly in the Chesapeake Bay in the eastern United States, have experienced severe declines. Blue crabs also play a key role in managing the populations of the animals they prey on, and constant overharvesting has had wide-ranging negative effects on the ecosystems they inhabit. For this reason, comprehensive management schemes are in place in several parts of the blue crab's range.

WATCH: Blue Crab vs. Clam

Watch as a blue crab works hard for its meal, and turns a clam into 'table scraps.'