Blue Crab
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40 free Blue Crab trivia questions with answers — trivia quiz, new questions added Oct 2026.
The blue crab is the best-loved shellfish of America's Atlantic and Gulf coasts, steamed by the bushel every summer and picked apart at kitchen tables from New Jersey to Texas. Behind the sweet meat is an aggressive, restless animal that outgrows its own armour again and again, travels between river and ocean, and has a few habits that surprise even people who eat it every week. This quiz gathers the fun facts people go looking for: how to tell males from females, what the scientific name means, what the crab eats and what eats it, how it gets through the cold months, how crabbers catch it, and the dishes, slang and traditions that have grown up around it. A few questions follow the crab overseas, where it has turned up uninvited. It suits crabbers, seafood lovers, students and anyone heading for Chesapeake Bay or the Gulf Coast. Every answer comes with a short explanation, so you finish knowing more than when you started.
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Q 01When a blue crab is cooked and its blue pigment breaks down, which colour does the shell turn?
Orange-red
Orange-red is the colour of astaxanthin, a pigment that survives the heat. In a live crab it is masked by a blue pigment that cooking destroys.
Q 02Chesapeake crabbers say the narrow apron under a male blue crab looks like which landmark?
Washington Monument
The Washington Monument is the local shorthand for a male's slender apron. A mature female's rounded apron is compared to the dome of the US Capitol.
Q 03Which Chesapeake Bay state made the blue crab its official state crustacean?
Maryland
Maryland gave the blue crab the title in 1989. The crab is the state's most valuable commercial fishery and the heart of its crab cakes and summer crab feasts.
Q 04Which grim habit forces a freshly molted blue crab to hide until its shell hardens?
Cannibalism
Cannibalism is routine for blue crabs, which eat almost anything they can find, including smaller and soft-shelled crabs of their own species.
Q 05Which Baltimore spice blend, created in 1939, is chiefly used to season blue crabs and shrimp?
Old Bay
Old Bay is named after the Old Bay Line, a steamship company that sailed out of Baltimore. Its creator, Gustav Brunn, was a spice merchant who had fled Nazi Germany.
Q 06The second half of the blue crab's scientific name, sapidus, is a Latin word meaning what?
Savory
Savory is what sapidus means, a compliment to the crab's sweet meat. Zoologist Mary Rathbun gave the species its name in 1896.
Q 07After mating just once in her life, a female blue crab stores what for up to a year?
Sperm
Sperm kept from that single mating lets her fertilise several batches of eggs months later, after she has migrated to saltier water.
Q 08How do blue crabs in Chesapeake Bay spend the winter once the water turns cold?
Buried in bottom mud
Buried in bottom mud, the crabs rest until spring. Scientists use the lull to count them, sampling the bay bottom in a yearly winter dredge survey.
Q 09Blue crabs can see in almost every direction at once thanks to which feature?
Stalked compound eyes
Stalked compound eyes give the crab a near all-round view. They also see in colour: studies show blue crabs use colour vision when choosing a mate.
Q 10Besides her broader apron, which feature marks out a mature female blue crab from a male?
Red-tipped claws
Red-tipped claws set her apart from a male, whose claws are bright blue. Courtship studies found that males prefer females showing red on their claws.
Q 11Which Gulf state's blue crab fishery was the world's first to be certified as sustainable, in 2012?
Louisiana
Louisiana won the Marine Stewardship Council's label in 2012, and must pass yearly monitoring to keep it. The state lands over half of all blue crab caught in the Gulf of Mexico.
Q 12Which European country named a 'commissioner for the blue crab' as the invader ate its clams?
Italy
Italy created the post as blue crabs spread through the Po delta and along the Adriatic coast. Local authorities and fishermen there are working together to try to eradicate it.
Q 13How did blue crabs from the Americas most likely reach European and Japanese waters?
In ships' ballast water
Q 21Which fortified wine is traditionally added to she-crab soup, a rich blue crab bisque, at serving?
Sherry
Sherry goes in as the soup is plated, a small dry splash over a bisque enriched with cream and crab roe. The dish is a speciality of the South Carolina Lowcountry.
Q 22What nickname do Atlantic coast seafood lovers give the yellowish organ inside a blue crab's body?
The mustard
The mustard is the crab's hepatopancreas, named for its colour. When a soft-shell crab is cleaned, fans ask the vendor to leave it in.
Q 23A traditional Chesapeake crab cake is built around which prized grade of blue crab meat?
Jumbo lump
Jumbo lump goes in with only a very small amount of binder. The cakes are chilled before cooking so that they hold together without extra filler.
In ships' ballast water is how the species is thought to have travelled. Europe's first was recorded at Rochefort, France, around 1900, and it now lives as far east as the Black Sea.
Q 14Which endangered bird leans heavily on blue crabs for food while wintering on the Texas coast?
Whooping crane
The whooping crane winters at Aransas National Wildlife Refuge, where blue crabs have supplied up to 90 percent of its energy intake in some winters.
Q 15Which bait do recreational crabbers traditionally tie to a string to lure blue crabs to a dip net?
Chicken necks
Chicken necks, or sometimes a fish head, go on the string. When a crab tugs, the line is eased in slowly so a net can scoop the crab up before it lets go.
Q 16What name is given to the rare event when low-oxygen water drives blue crabs to crawl onto land?
A jubilee
A jubilee, or crab jubilee, is a warning sign rather than a party: the crabs are fleeing water so short of oxygen that staying would suffocate them.
Q 17What do crabbers call the mass of eggs that a female blue crab carries under her apron?
A sponge
A sponge darkens as the larvae inside use up their yolk. After about two weeks the female releases them near the mouth of the estuary.
Q 18Roughly how many eggs can a single female blue crab carry in one brood?
About 2 million
About 2 million eggs can ride in a single brood, yet almost none make it: by one estimate only one egg in a million survives to become an adult.
Q 19What becomes of the missing limb when a blue crab loses a claw or leg in a fight?
It regrows as it molts
It regrows as it molts, though not at once: a replacement claw or leg takes two or more sheddings of the shell to appear.
Q 20Chesapeake crabbers have which nickname for an adult male blue crab, especially a big one?
Jimmy
Jimmy is the name for a male, while a mature female is a sook. The biggest jimmies tend to come from rivers such as the Wye and the Chester.
Q 24Which William W. Warner book about blue crabs and their catchers won a 1977 Pulitzer Prize?
Beautiful Swimmers
Beautiful Swimmers takes its title from the crab's genus name, Callinectes, which is Greek for exactly that. The book stayed in print for the rest of its author's life.
Q 25What traditional name is used for the people who harvest blue crabs and oysters on Chesapeake Bay?
Watermen
Watermen work the bay all year, crabbing and oystering from V-hulled workboats. In England the same word once meant the boatmen who ferried passengers on the Thames.
Q 26Which turtle often drowns in blue crab pots, leading crabbers to fit excluder devices?
Diamondback terrapin
The diamondback terrapin shares the crab's coastal range, and small ones slip through a pot's flexible funnels. Excluder devices keep them out without reducing the crab catch.
Q 27Which Chesapeake Bay seagrass, prone to die-offs in hot summers, is essential habitat for juvenile blue crabs?
Eelgrass
Eelgrass beds shelter young crabs, and females need them for their final molt. In 2005, high temperatures caused a massive die-off of the plant in Chesapeake Bay.
Q 28By eating which grass-grazing marsh snail do blue crabs help protect salt marshes from damage?
Periwinkle
Periwinkle snails feed on marsh grasses, so scientists worry that a drop in blue crab numbers would leave more snails grazing and less marsh standing.
Q 29Female blue crabs nearing their final molt attract a mate by releasing a pheromone in which fluid?
Urine
Urine carries the chemical signal, and males compete to answer it. The winner guards the female until she molts and mating can begin.
Q 30Why were abundant blue crabs once considered a nuisance by fishermen in the lower Chesapeake Bay?
They clogged fishing nets
They clogged fishing nets so often that seine crews treated them as pests. The same crab is now the most valuable commercial fishery in the bay.