What Do Crabs Eat?

As omnivores, crabs eat a variety of plants and animals to maintain their health. They feed upon algae, fungi, bacteria and leaves of plants. If they are hungry for animal matter they eat mollusks, worms and other crustaceans such as shrimp, crayfish, krill and barnacles.

The health and fitness of crabs is based upon whether the crab consumes a balanced diet of plant life and animal matter. As such, within the commercial crabbing industry, it is important to know what crabs eat to properly bait the traps and maximize the catch.

Description of Crabs

Crabs are crustaceans that have eight walking legs and have two claws in the front with which they defend themselves and obtain food. Their eight legs don't have feet in the bottom: some end in a point and others end in a flipper to help them swim.

Crabs evolved from two distinct lines during the Jurassic period. They are identified in the fossil record by their carapace.

The pointed legs help the crab move on land or across the sea floor. They are designed to either pull or push the crab along. The crab seldom moves straight forward but instead moves sideways. While the legs on one side pull the legs, the legs on the other side push the crab.

Their colors vary depending on the environment that they live in so that they are able to camouflage.

Male and Female Crabs

Crabs have distinct features that differentiate the males from the females.

Males have larger claws than the female and their abdomen differ in sharpness and width. The abdomen of the crab appears on the underside of the crab and can be pulled away from the main part of the body.
Females have a wider rounded abdomen while the male’s abdomen is a sharper point and narrow.

Crab Claws

Crabs use their claws not only to eat with and to defend themselves, but also to communicate with each other. The claws play an important role in the mating rituals as well. Crabs, particularly males, drum their pinchers to attract females for mating.

Crabs also use their pinchers to drum or wave to communicate to other crabs.

Their behavior to other crabs is often aggressive. The males tend to fight one another for access to a female. Another reason for fighting among crabs is for possession of select hiding places in caves and rocky areas that provide cover.

Crab Reproduction

The reproduction habits of crabs are interesting as well. The male delivers his sperm to the female for egg fertilization via the gonophores located on the legs. They then find a comfortable place for the female to lay her brood and watch over them until they hatch. The first two sets of appendages are used for sperm transfer and therefore the gonophores are located more towards the midline of the body.

Eating Crab

Crabs are one of the most consumed crustaceans and approximately 1.5 million ton of crab is consumed annually. There is a commercial fishing industry surrounding crabs and they amount to 20 percent of all crustaceans caught and raised annually.

The most fished species is the Japanese blue crab or horse crab. More than 98 percent are caught off the coast in the China Sea. Other commercially important species are dungeness from the cold Pacific Northwest waters and the blue crab from the cooler waters of the Chesapeake Bay and eastern seaboard.

A traditional way to prepare crabs involves boiling the crab in salted water with lots of spices to flavor the meat.

Two particularly heavily spiced dishes include masala crab and chili crab, which are specialties in Asia. Other more common preparations include crab cakes and bisque. The Alaskan King Crab is also a popular culinary delight. The Alaskan King Crab is one of the most sought after species for the worldwide market; but, fishing for it in the icy waters of the Bering Sea and in the waters off the Aleutian Islands is one of the deadliest professions on earth.