Animal Profiles
Crustaceans

Crab

Brachyura

Living

Living individuals or members of this group exist today. This does not mean they are safe from extinction.

True crabs include many forms. This account follows the Atlantic blue crab (Callinectes sapidus), a swimming crab that inhabits estuaries and coastal waters.

Atlantic blue crab (Callinectes sapidus), photographed for NOAA in Narragansett Bay, Rhode Island.

Atlantic blue crab (Callinectes sapidus), photographed for NOAA in Narragansett Bay, Rhode Island.

At a glance

Location
Atlantic blue crabs occupy western Atlantic coastal habitats, especially estuaries where freshwater meets the sea.
Habitat
Coast, Wetlands
Diet
Omnivore
Food
Molluscs, other animals and plant material all enter the diet.

Classification

Common name
Crab
Browse group
Crustaceans
Scientific name or taxon
Brachyura
Source classification
Malacostraca

Three things to know

  • Its rear legs form swimming paddles.
  • It sheds its shell to grow.
  • It eats both animal and plant foods.

Habitat and range

Atlantic blue crabs occupy western Atlantic coastal habitats, especially estuaries where freshwater meets the sea. Salinity and season influence where different life stages occur.

Appearance and adaptations

The broad shell extends into points at the sides. The final pair of legs is flattened into paddles, and the claws and other front appendages often show blue coloration.

Diet and behaviour

Molluscs, other animals and plant material all enter the diet. Blue crabs can also scavenge. Growth requires shedding the old shell, followed by a vulnerable period while the new covering hardens.

Sources

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