Crabs

Natural History

Blue crabs (Callinectes sapidus) live primarily in the Chesapeake Bay and are known scavengers. They will eat a large variety of plants and animals in the Bay including decaying plants and animals, small fish, and other crabs (even other Blue Crabs). Blue crabs also have unique, hinging mouths that split and open for them to eat food.

Male blue crabs are usually referred to as “Jimmy Crabs,” immature female crabs are called “she crabs” or “Sally” crabs, and mature females are called “sooks”. Males can be distinguished from females by the apron on its abdomen. Male blue crabs have a “T” shaped apron while mature females have a dark “U” shaped apron and immature females have a light “V” shaped apron. Female blue crabs carry eggs in masses under their abdomen. These masses are bright orange and spongy. At this point the female is called a “sponge crab.”

A blue crab has 10 legs which include 2 swimmers, 6 legs, and 2 pinchers. The pinchers are located in the front of their body and the flippers are towards its rear. The legs are located in the middle of the pinchers and the flippers. The pinchers are the blue crabs main source of protection.  If a blue crab loses a limb at any point of its life, the crab will go through a regeneration process to grow that limb back. After a crab has molted its shell, it is called a “soft crab” until his shell hardens again. The crab is very vulnerable as a “soft crab.”

Fun Facts

  • Blue crab’s scientific name, Callinectes sapidus, translates to “beautiful swimmer that is savory” in Latin.
  • The crab molts its shell 18 to 20 times before it is mature at 1 to 1 1/2 years old. After this period, males continue to molt and grow, and females stop molting.
  • Female blue crabs have red “painted” tips on its front two pinchers, whereas male blue crabs have unpainted blue pinchers.
  • The blue crabs bury themselves in the mud during the winter season and come out of hibernation in the spring.
  • Blue crabs can regenerate limbs if broken off.
  • After molting, a crab’s new shell will be soft and referred to as “soft” crab until the shell hardens.
  • A sook carrying eggs along its abdomen is referred to as a “sponge” crab.

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