Blue Crab

Blue Crab

Callinectes sapidus


This animal has three pairs of legs and walks sideways.

Exhibit Name and Location:
Baltimore - Maryland: Mountains to the Sea

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Blue Crab

In spite of their colorful name, blue crabs are mostly grayish to bluish green. Only the claws are blue, and the claws of mature females also have bright orange-red tips.

There’s another easy way to distinguish males from females: Maryland locals look for the "apron." Males have a T-shaped abdomen, and females have triangular abdomens that become rounder as they age.

Crabs grow by shedding their shells, a process called molting. They take in water to expand and break out of the old shell. A new soft shell underneath hardens quickly.

With three pairs of walking legs, they generally walk sideways, clearing a path with sharp lateral spines. Large, powerful claws are used for defense, digging, sexual displays, and to gather food.

Crabbing is part of Maryland's heritage, and a local favorite summer "tribal ritual" is a crab feast.

Heaps of steamed blue crabs (now red, after steaming), spicy and hot, are piled high on newspaper-covered tables and eagerly devoured in backyards, restaurants, and picnic sites. Nearly every Marylander has his or her own recipe for steamed blue crabs.

Blue Crab Facts


Adult blue crabs feed on bivalves, crustaceans, fish, worms, plants, detritus, and nearly anything else they can find, including dead fish and plants.

The blue crab's favorite food may be thin-shelled bivalves. When these are scarce, they resort to cannibalism on juvenile crabs.


Males typically grow larger than females, sometimes reaching 7–8 inches from point to point, although 5 inches is the legal size for harvesting. Reportedly, some males have grown to about 10 inches.


Blue crabs are bottom-dwelling predators that live along the Atlantic coast, from Cape Cod to Florida.

Population Status

Cannibalism of young blue crabs by larger crabs is common and it may regulate population abundance.

Conservation alert! Loss of habitat, combined with the blue crab’s popularity as a food for humans, has led to serious drops in populations. The population of Chesapeake Bay crabs has grown since 2001, but the future remains uncertain.

Habitat restoration is essential for crab recovery. The National Aquarium invites you to help us restore marshes throughout the Chesapeake Bay.


Some bony fish, as well as some sharks and rays, feed on juveniles and larger crabs, and the blue crab is the preferred food of the Atlantic ridley sea turtle.

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Jack Cover
General Curator

pressroom striped fish

As the general curator, Jack's role is to ensure that our living animal collections are thriving and diverse, to best exhibit the beauty of the wild habitats we represent here at the Aquarium. Learn More

A Note From the Caretaker

If you notice what seems to be a dead crab in the exhibit, relax! The crab molts periodically by backing out of its shell, and the old shell in the exhibit is sometimes mistaken for a dead crab.

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